Vitriol MakingA—Caldron. B—Moulds. C—Cakes.[Pg 577]The fourth method of making vitriol is from vitriolous earth or stones. Such ore is at first carried and heaped up, and is then left for five or six months exposed to the rain of spring and autumn, to the heat of summer, and to the rime and frost of winter. It must be turned over several times with shovels, so that the part at the bottom may be brought to the top, and it is thus ventilated and cooled; by this means the earth crumbles up and loosens, and the stone changes from hard to soft. Then the ore is covered with a roof, or else it is taken away and placed under a roof, and remains in that place six, seven, or eight months. Afterward as large a portion as is required is thrown into a vat, which is half-filled with water; this vat is one hundredfeet long, twenty-four feet wide, eight feet deep. It has an opening at the bottom, so that when it is opened the dregs of the ore from which the vitriol comes may be drawn off, and it has, at the height of one foot from the bottom, three or four little holes, so that, when closed, the water may be retained, and when opened the solution flows out. Thus the ore is mixed with water, stirred with poles and left in the tank until the earthy portions sink to the bottom and the water absorbs the juices. Then the little holes are opened, the solution flows out of the vat, and is caught in a vat below it; this vat is of the same length as the other, but twelve feet wide and four feet deep. If the solution is not sufficiently vitriolous it is mixed with fresh ore; but if it contains enough vitriol, and yet has not exhausted all of the ore rich in vitriol, it is well to dissolve the ore again with fresh water. As soon as the solution becomes clear, it is poured into the rectangular leaden caldron through launders, and is boiled until the water is evaporated. Afterward as many thin strips of iron as the nature of the solution requires, are thrown in, and then it is boiled again until it is thick enough, when cold, to congeal into vitriol. Then it is poured into tanks or vats, or any other receptacle, in which all of it that is apt to congeal does so within two or three days. The solution which does not congeal is either poured back into the caldron to be boiled again, orit is put aside for dissolving the new ore, for it is far preferable to fresh water. The solidified vitriol is hewn out, and having once more been thrown into the caldron, is re-heated until it liquefies; when liquid, it is poured into moulds that it may be made into cakes. If the solution first poured out is not satisfactorily thickened, it is condensed two or three times, and each time liquefied in the caldron and re-poured into the moulds, in which manner pure cakes, beautiful to look at, are made from it.
The vitriolous pyrites, which are to be numbered among the mixtures (mistura), are roasted as in the case of alum, and dissolved with water, and the solution is boiled in leaden caldrons until it condenses into vitriol. Both alum and vitriol are often made out of these, and it is no wonder, for these juices are cognate, and only differ in the one point,—that the former is less, the latter more, earthy. That pyrites which contains metal must be smelted in the furnace. In the same manner, from other mixtures of vitriolic and metalliferous material are made vitriol and metal. Indeed, if ores of vitriolous pyrites abound, the miners split small logs down the centre and cut them off in lengths as long as the drifts and tunnels are wide, in which they lay them down transversely; but, that they may be stable, they are laid on the ground with the wide side down and the round side up, and they touch each other at the bottom, but not at the top. The intermediate space is filled with pyrites, and the same crushed are scattered over the wood, so that, coming in or going out, the road is flat and even. Since the drifts or tunnels drip with water, these pyrites are soaked, and from them are freed the vitriol and cognate things. If the water ceases to drip, these dry and harden, and then they are raised from the shafts, together with the pyrites not yet dissolved in the water, or they are carried out from the tunnels; then they are thrown into vats or tanks, and boiling water having been poured over them, the vitriol is freed and the pyrites are dissolved. This green solution is transferred to other vats or tanks, that it may be made clear and pure; it is then boiled in the lead caldrons until it thickens; afterward it is poured into wooden tubs, where it condenses on rods, or reeds, or twigs, into green vitriol.
Sulphur is made from sulphurous waters, from sulphurous ores, and from sulphurous mixtures. These waters are poured into the leaden caldrons and boiled until they condense into sulphur. From this latter, heated together with iron-scales, and transferred into pots, which are afterward covered with lute and refined sulphur, another sulphur is made, which we callcaballinum.[12]
Sulphur MakingA—Pots having spouts. B—Pots without spouts. C—Lids.[Pg 579]The ores[13]which consist mostly of sulphur and of earth, and rarely of other minerals, are melted in big-bellied earthenware pots. The furnaces,which hold two of these pots, are divided into three parts; the lowest part is a foot high, and has an opening at the front for the draught; the top of this is covered with iron plates, which are perforated near the edges, and these support iron rods, upon which the firewood is placed. The middle part of the furnace is one and a half feet high, and has a mouth in front, so that the wood may be inserted; the top of this has rods, upon which the bottom of the pots stand. The upper part is about two feet high, and the pots are also two feet high and one digit thick; these have below their mouths a long, slender spout. In order that the mouth of the pot may be covered, an earthenware lid is made which fits into it. For every two of these pots there must be one potof the same size and shape, and without a spout, but having three holes, two of which are below the mouth and receive the spouts of the two first pots; the third hole is on the opposite side at the bottom, and through it the sulphur flows out. In each furnace are placed two pots with spouts, and the furnace must be covered by plates of iron smeared over with lute two digits thick; it is thus entirely closed in, but for two or three vent-holes through which the mouths of the pots project. Outside of the furnace, against one side, is placed the pot without a spout, into the two holes of which the two spouts of the other pots penetrate, and this pot should be built in at both sides to keep it steady. When the sulphur ore has been placed in the pots, and these placed in the furnace, they are closely covered, and it is desirable to smear the joint over with lute, so that the sulphur will not exhale, and for the same reason the pot below is covered with a lid, which is also smeared with lute. The wood having been kindled, the ores are heated until the sulphur is exhaled, and the vapour, arising through the spout, penetrates into the lower pot and thickens into sulphur, which falls to the bottom like melted wax. It then flows out through the hole, which, as I said, is at the bottom of this pot; and the workman makes it into cakes, or thin sticks or thin pieces of wood are dipped in it. Then he takes the burning wood and glowing charcoal from the furnace, and when it has cooled, he opens the two pots, empties the residues, which, if the ores were composed of sulphur and earth, resemble naturally extinguished ashes; but if the ores consisted of sulphur and earth and stone, or sulphur and stone only, they resemble earth completely dried or stones well roasted. Afterward the pots are re-filled with ore, and the whole work is repeated.
Sulphur MakingA—Long wall. B—High walls. C—Low walls. D—Plates. E—Upper pots. F—Lower pots.[Pg 581]The sulphurous mixture, whether it consists of stone and sulphur only, or of stone and sulphur and metal, may be heated in similar pots, but with perforated bottoms. Before the furnace is constructed, against the "second" wall of the works two lateral partitions are built seven feet high, three feet long, one and a half feet thick, and these are distant from each other twenty-seven feet. Between them are seven low brick walls, that measure but two feet and the same number of digits in height, and, like the other walls, are three feet long and one foot thick; these little walls are at equal distances from one another, consequently they will be two and one half feet apart. At the top, iron bars are fixed into them, which sustain iron plates three feet long and wide and one digit thick, so that they can bear not only the weight of the pots, but also the fierceness of the fire. These plates have in the middle a round hole one and a half digits wide; there must not be more than eight of these, and upon them as many pots are placed. These pots are perforated at the bottom, and the same number of whole pots are placed underneath them; the former contain the mixture, and are covered with lids; the latter contain water, and their mouths are under the holes in the plates. After wood has been arranged round the upper pots and ignited, the mixture being heated, red, yellow, or green sulphur drips from it and flows down through the hole, and is caught by the pots placed underneath the plates, and is at once cooled by the water. If the mixture contains metal, it is reserved for smelting, and, if not, it is thrown away.The sulphur from such a mixture can best be extracted if the upper pots are placed in a vaulted furnace, like those which I described among other metallurgical subjects inBook VIII., which has no floor, but a grate inside; under this the lower pots are placed in the same manner, but the plates must have larger holes.
Bitumen MakingA—Lower pot. B—Upper pot. C—Lid.[Pg 582]Others bury a pot in the ground, and place over it another pot with a hole at the bottom, in which pyrites orcadmia, or other sulphurous stones are so enclosed that the sulphur cannot exhale. A fierce fire heats the sulphur, and it drips away and flows down into the lower pot, which contains water. (Illustration p.582).
Bitumen MakingA—Bituminous spring. B—Bucket. C—Pot. D—Lid.[Pg 583]Bitumen[14]is made from bituminous waters, from liquid bitumen, and from mixtures of bituminous substances. The water, bituminous as well assalty, at Babylon, as Pliny writes, was taken from the wells to the salt works and heated by the great heat of the sun, and condensed partly into liquid bitumen and partly into salt. The bitumen being lighter, floats on the top, while the salt being heavier, sinks to the bottom. Liquid bitumen, if there is much floating on springs, streams and rivers, is drawn up in buckets or other vessels; but, if there is little, it is collected with goose wings, piecesof linen,ralla, shreds of reeds, and other things to which it easily adheres, and it is boiled in large brass or iron pots by fire and condensed. As this bitumen is put to divers uses, some mix pitch with the liquid, others old cart-grease, in order to temper its viscosity; these, however long they areboiled in the pots, cannot be made hard. The mixtures containing bitumen are also treated in the same manner as those containing sulphur, in pots having a hole in the bottom, and it is rare that such bitumen is not highly esteemed.
Chrysocolla MakingA—Mouth of the tunnel. B—Trough. C—Tanks. D—Little trough.[Pg 585]Since all solidified juices and earths, if abundantly and copiously mixed with the water, are deposited in the beds of springs, streams or rivers, and the stones therein are coated by them, they do not require the heat of the sun or fire to harden them. This having been pondered over by wise men, they discovered methods by which the remainder of these solidified juices and unusual earths can be collected. Such waters, whether flowing from springs or tunnels, are collected in many wooden tubs or tanks arranged in consecutive order, and deposit in them such juices or earths; these being scraped off every year, are collected, aschrysocolla[15]in the Carpathians and as ochre in the Harz.
There remains glass, the preparation of which belongs here, for the reason that it is obtained by the power of fire and subtle art from certain solidified juices and from coarse or fine sand. It is transparent, as are certain solidified juices, gems, and stones; and can be melted like fusible stones and metals. First I must speak of the materials from which glass is made; then of the furnaces in which it is melted; then of the methods by which it is produced.
It is made from fusible stones and from solidified juices, or from other juicy substances which are connected by a natural relationship. Stones which are fusible, if they are white and translucent, are more excellent thanthe others, for which reason crystals take the first place. From these, when pounded, the most excellent transparent glass was made in India, with which no other could be compared, as Pliny relates. The second place is accorded to stones which, although not so hard as crystal, are yet just as white and transparent. The third is given to white stones, which are not transparent. It is necessary, however, first of all to heat all these, and afterward they are subjected to the pestle in order to break and crush them into coarse sand, and then they are passed through a sieve. If this kind of coarse or fine sand is found by the glass-makers near the mouth of a river, it saves them much labour in burning and crushing. As regards the solidified juices, the first place is given to soda; the second to white and translucent rock-salt; the third to salts which are made from lye, from the ashes of the musk ivy, or from other salty herbs. Yet there are some who give to this latter, and not to the former, the second place. One part of coarse or fine sand made from fusible stones should be mixed with two parts of soda or of rock-salt or of herb salts, to which are added minute particles ofmagnes.[16]It is true that in ourday, as much as in ancient times, there exists the belief in the singular power of the latter to attract to itself the vitreous liquid just as it does iron, and by attracting it to purify and transform green or yellow into white; and afterward fire consumes themagnes. When the said juices are not to be had, two parts of the ashes of oak or holmoak, or of hard oak or Turkey oak, or if these be not available, of beech or pine, are mixed with one part of coarse or fine sand, and a small quantity of salt is added, made from salt water or sea-water, and a small particle ofmagnes; but these make a less white and translucent glass. The ashes should be made from old trees, of which the trunk at a height of six feet is hollowed out and fire is put in, and thus the whole tree is consumed and converted into ashes. This is done in winter when the snow lies long, or in summer when it does not rain, for the showers at other times of the year, by mixing the ashes with earth, render them impure; for this reason, at such times, these same trees are cut up into many pieces and burned under cover, and are thus converted into ashes.
Glass-making FurnaceA—Lower chamber of the first furnace. B—Upper chamber. C—Vitreous mass.[Pg 587]Some glass-makers use three furnaces, others two, others only one. Those who use three, melt the material in the first, re-melt it in the second,and in the third they cool the glowing glass vessels and other articles. Of these the first furnace must be vaulted and similar to an oven. In the upper chamber, which is six feet long, four feet wide, and two feet high, the mixed materials are heated by a fierce fire of dry wood until they melt and are converted into a vitreous mass. And if they are not satisfactorily purified from dross, they are taken out and cooled and broken into pieces; and the vitreous pieces are heated in pots in the same furnace.
Glass-making FurnaceA—Arches of the second furnace. B—Mouth of the lower chamber. C—Windows of the upper chamber. D—Big-bellied pots. E—Mouth of the third furnace. F—Recesses for the receptacles. G—Openings in the upper chamber. H—Oblong receptacles.[Pg 588]The second furnace is round, ten feet in diameter and eight feet high, and on the outside, so that it may be stronger, it is encompassed by five arches, one and one half feet thick; it consists in like manner of two chambers, of which the lower one is vaulted and is one and one half feet thick. In front this chamber has a narrow mouth, through which the wood can be put into the hearth, which is on the ground. At the top and in the middle of its vault, there is a large round hole which opens to the upper chamber, so that the flames can penetrate into it. Between the arches in the walls of the upper chamber are eight windows, so large that the big-bellied pots may be placed through them on to the floor of the chamber, around the large hole. The thickness of these pots is about two digits, their height the same number of feet, and the diameter of the belly one and a halffeet, and of the mouth and bottom one foot. In the back part of the furnace is a rectangular hole, measuring in height and width a palm, through which the heat penetrates into a third furnace which adjoins it.
This third furnace is rectangular, eight feet long and six feet wide; it also consists of two chambers, of which the lower has a mouth in front, so that firewood may be placed on the hearth which is on the ground. On each side of this opening in the wall of the lower chamber is a recess for oblong earthenware receptacles, which are about four feet long, two feet high, and one and a half feet wide. The upper chamber has two holes, one on the right side, the other on the left, of such height and width that earthenware receptacles may be conveniently placed in them. These latter receptacles are three feet long, one and a half feet high, the lower part one foot wide, and the upper part rounded. In these receptacles the glass articles, which have been blown, are placed so that they may cool in a milder temperature; if they were not cooled slowly they would burst asunder. When the vessels are taken from the upper chamber, they are immediately placed in the receptacles to cool.
Glass-making FurnacesA—Lower chamber of the other second furnace. B—Middle one. C—Upper one. D—Its opening. E—Round opening. F—Rectangular opening.[Pg 589]Some who use two furnaces partly melt the mixture in the first, and not only re-melt it in the second, but also replace the glass articles there. Others partly melt and re-melt the material in different chambers of the second furnace. Thus the former lack the third furnace, and the latter, the first. But this kind of second furnace differs from the other second furnace, for it is, indeed, round, but the interior is eight feet in diameter and twelve feet high, and it consists of three chambers, of which the lowest is not unlike the lowest of the other second furnace. In the middle chamber wall there are six arched openings, in which are placed the pots to be heated, and the remainder of the small windows are blocked up with lute. In the middle top of the middle chamber is a square opening a palm in length and width. Through this the heat penetrates into the upper chamber, of which the rear part has an opening to receive the oblong earthenware receptacles, in which are placed the glass articles to be slowly cooled. On this side, the ground of the workshop is higher, or else a bench is placed there, so that the glass-makers may stand upon it to stow away their products more conveniently.
Those who lack the first furnace in the evening, when they have accomplished their day's work, place the material in the pots, so that the heat during the night may melt it and turn it into glass. Two boys alternately, during night and day, keep up the fire by throwing dry wood on to the hearth. Those who have but one furnace use the second sort, made with three chambers. Then in the evening they pour the material into the pots, and in the morning, having extracted the fused material, they make the glass objects, which they place in the upper chamber, as do the others.
The second furnace consists either of two or three chambers, the first of which is made of unburnt bricks dried in the sun. These bricks are made of a kind of clay that cannot be easily melted by fire nor resolved into powder; this clay is cleaned of small stones and beaten with rods. The bricks are laid with the same kind of clay instead of lime. From the same clay the potters also make their vessels and pots, which they dry in the shade. These two parts having been completed, there remains the third.
Glass MakingA—Blow-pipe. B—Little window. C—Marble. D—Forceps. E—Moulds by means of which the shapes are produced.[Pg 591]The vitreous mass having been made in the first furnace in the manner I described, is broken up, and the assistant heats the second furnace, in order that the fragments may be re-melted. In the meantime, while they are doing this, the pots are first warmed by a slow fire in the first furnace, so that the vapours may evaporate, and then by a fiercer fire, so that they become red in drying. Afterward the glass-makers open the mouth of the furnace, and, seizing the pots with tongs, if they have not cracked and fallen to pieces, quickly place them in the second furnace, and they fill them up with the fragments of the heated vitreous mass or with glass. Afterward they close up all the windows with lute and bricks, with the exception that in each there are two little windows left free; through one of these they inspect the glass contained in the pot, and take it up by means of a blow-pipe; in the other they rest another blow-pipe, so that it may get warm. Whether it is made of brass, bronze, or iron, the blow-pipe must be three feet long.In front of the window is inserted a lip of marble, on which rests the heaped-up clay and the iron shield. The clay holds the blow-pipe when it is put into the furnace, whereas the shield preserves the eyes of the glass-maker from the fire. All this having been carried out in order, the glass-makers bring the work to completion. The broken pieces they re-melt with dry wood, which emits no smoke, but only a flame. The longer they re-melt it, the purer and more transparent it becomes, the fewer spots and blisters there are, and therefore the glass-makers can carry out their work more easily. For this reason those who only melt the material from which glass is made for one night, and then immediately make it up into glass articles, make them less pure and transparent than those who first produce a vitreous mass and then re-melt the broken pieces again for a day and a night. And, again, these make a less pure and transparent glass than do those who melt it again for two days and two nights, for the excellence of the glass does not consist solely in the material from which it is made, but also in the melting. The glass-makers often test the glass by drawing it up with the blowpipes; as soon as they observe that the fragments have been re-melted and purified satisfactorily, each of them with another blow-pipe which is in the pot, slowly stirs and takes up the glass which sticks to it in the shape of a ball like a glutinous, coagulated gum. He takes up just as much as he needs to complete the article he wishes to make; then he presses it against the lip of marble and kneads it round and round until it consolidates. When he blows through the pipe he blows as he would if inflating a bubble; he blows into the blow-pipe as often as it is necessary, removing it from his mouth to re-fill his cheeks, so that his breath does not draw the flames into his mouth. Then, twisting the lifted blow-pipe round his head in a circle, he makes a long glass, or moulds the same in a hollow copper mould, turning it round and round, then warming it again, blowing it and pressing it, he widens it into the shape of a cup or vessel, or of any other object he has in mind. Then he again presses this against the marble to flatten the bottom, which he moulds in the interior with his other blow-pipe. Afterward he cuts out the lip with shears, and, if necessary, adds feet and handles. If it so please him, he gilds it and paints it with various colours. Finally, he lays it in the oblong earthenware receptacle, which is placed in the third furnace, or in the upper chamber of the second furnace, that it may cool. When this receptacle is full of other slowly-cooled articles, he passes a wide iron bar under it, and, carrying it on the left arm, places it in another recess.
The glass-makers make divers things, such as goblets, cups, ewers, flasks, dishes, plates, panes of glass, animals, trees, and ships, all of which excellent and wonderful works I have seen when I spent two whole years in Venice some time ago. Especially at the time of the Feast of the Ascension they were on sale at Morano, where are located the most celebrated glass-works. These I saw on other occasions, and when, for a certain reason, I visited Andrea Naugerio in his house which he had there, and conversed with him and Francisco Asulano.
END OF BOOK XII.
FOOTNOTES:[Pg 546][1]The history of salt-making in salt-pans, from sea-water or salt springs, goes further back than human records. From an historical point of view the real interest attached to salt lies in the bearing which localities rich in either natural salt or salt springs, have had upon the movements of the human race. Many ancient trade routes have been due to them, and innumerable battles have been fought for their possession. Salt has at times served for currency, and during many centuries in nearly every country has served as a basis of taxation. These subjects do not, however, come within the scope of this text. For the quotation from Pliny referred to, seeNote 14 below, on bitumen.[2]The first edition givesgraviorem, the latter editionsgratiorem, which latter would have quite the reverse meaning from the above.[Pg 550][3]The following are approximately the English equivalents:—Pints.Quarts.Gallons.1Cyathus.083Cyathi=1Quartarius.244Quartarii=1Sextarius.996Sextarii=1Congius5.942.9716Sextarii=1Modius15.857.931.988Congii=1Amphora47.5723.785.94The dipper mentioned would thus hold about one and one quarter gallons, and the cask ten gallons.[Pg 552][4]The salt industry, founded upon salt springs, is still of importance to this city. It was a salt centre of importance to the Germanic tribes before Charles, the son of Charlemagne, erected a fortress here in 806. Mention of the salt works is made in the charter by Otto I., conveying the place to the Diocese of Magdeburg, in 968.[Pg 558][5]PlinyXXXI., 39-40. "In the Gallic provinces in Germany they pour salt water upon burning wood. The Spaniards in a certain place draw the brine from wells, which they callMuria. They indeed think that the wood turns to salt, and that the oak is the best, being the kind which is itself salty. Elsewhere the hazel is praised. Thus the charcoal even is turned into salt when it is steeped in brine. Whenever salt is made with wood it is black."[6]We have elsewhere in this book used the word "soda" for the Latin termnitrum, because we believe as used by Agricola it was always soda, and because some confusion of this term with its modern adaptation for saltpetre (nitre) might arise in the mind of the reader. Fortunately, Agricola usually carefully mentions other alkalis, such as the product from lixiviation of ashes, separately from hisnitrum. In these paragraphs, however, he has soda and potash hopelessly mixed, wherefore we have here introduced the Latin term. The actual difference between potash and soda—thenitrumof the Ancients, and thealkaliof Geber (and the glossary of Agricola), was not understood for two hundred years after Agricola, when Duhamel made his well-known determinations; and the isolation of sodium and potassium was, of course, still later by fifty years. If the reeds and rushes described in this paragraph grew near the sea, the salt from lixiviation would be soda, and likewise the Egyptian product was soda, but the lixiviation of wood-ash produces only potash; as seen above, all are termednitrumexcept the first.Historical Notes.—The wordnitrum,nitron,nitri,neter,nether, or similar forms, occurs in innumerable ancient writings. Among such references are Jeremiah (II., 22) Proverbs (XXV., 20), Herodotus (II., 86, 87), Aristotle (Prob.I., 39,De Mirab.54), Theophrastus (De Igne435 ed. Heinsii, Hist. PlantsIII., 9), Dioscorides (V., 89), Pliny (XIV., 26, andXXXI., 46). A review of disputations on what salts this term comprised among the Ancients would itself fill a volume, but from the properties named it was no doubt mostly soda, more rarely potash, and sometimes both mixed with common salt. There is every reason to believe from the properties and uses mentioned, that it did not generally comprise nitre (saltpetre)—into which superficial error the nomenclature has led many translators. The preparation by way of burning, and the use ofnitrumfor purposes for which we now use soap, for making glass, for medicines, cosmetics, salves, painting, in baking powder, for preserving food, embalming, etc., and the descriptions of its taste in "nitrous" waters,—all answer for soda and potash, but not for saltpetre. It is possible that the common occurrence of saltpetre as an efflorescence on walls might naturally lead to its use, but in any event its distinguishing characteristics are nowhere mentioned. As sal-ammoniac occurred[Pg 559]in the volcanoes in Italy, it also may have been included in thenitrummentioned.Nitrumwas in the main exported from Egypt, but Theophrastus mentions its production from wood-ash, and Pliny very rightly states that burned lees of wine (argol) had the nature ofnitrum. Many of the ancient writers understood that it was rendered more caustic by burning, and still more so by treatment with lime. According to Beckmann (Hist. of InventionsII., p. 488), the form of the wordnatronwas first introduced into Europe by two travellers in Egypt, Peter Ballon and Prosper Alpinus, about 1550. The word was introduced into mineralogy by Linnaeus in 1736. In the first instancenatronwas applied to[Pg 560]soda and potash in distinction tonitrefor saltpetre, and laternatronwas applied solely to soda.It is desirable to mention here two other forms of soda and potash which are frequently mentioned by Agricola. "Ashes which wool dyers use" (cineres quo infectores lanarum utuntur).—There is no indication in any of Agricola's works as to whether this was some special wood-ash or whether it was the calcined residues from wool washing. The "yolk" or "suint" of wool, originating from the perspiration of the animal, has long been a source of crude potash. The water, after washing the wool, is evaporated, and the residue calcined. It contains about 85% K2CO3, the remainder being sodium and potassium sulphates. Another reason for assuming that it was not a wood-ash product, is that these products are separately mentioned. In either event, whether obtained from wool residues or from lixiviation of wood-ash, it would be an impure potash. In some methods of wool dyeing, a wash of soda was first given, so that it is barely possible that this substance was sodium carbonate."Salt made from the ashes of musk ivy" (sal ex anthyllidis cinere factus,—Glossary,salalkali). This would be largely potash.[7]This wondrous illustration of soda-making from Nile water is no doubt founded upon Pliny (XXXI., 46). "It is made in almost the same manner as salt, except that sea-water is put into salt pans, whereas in the nitrous pans it is water of the Nile; these, with the subsidence of the Nile during the forty days, are impregnated withnitrum."[8]This paragraph displays hopeless ignorance. Borax was known to Agricola and greatly used in his time; it certainly was not made from these compounds, but was imported from Central Asia. Sal-ammoniac was also known in his time, and was used like borax as a soldering agent. The reaction given by Agricola would yield free ammonia. The following historical notes on borax and sal-ammoniac may be of service.Borax.—The uncertainties of the ancient distinctions in salts involve borax deeply. The wordBaurachoccurs in Geber and the other early Alchemistic writings, but there is nothing to prove that it was modern borax. There cannot be the slightest doubt, however, that the material referred to by Agricola asboraxwas our borax, because of the characteristic qualities incidentally mentioned inBook VII. That he believed it was an artificial product fromnitrumis evident enough from his usual expression "chrysocollamade fromnitrum, which the Moors callborax." Agricola, inDe Natura Fossilium(p. 206-7), makes the following statements, which could leave no doubt on the subject:—"Nativenitrumis found in the earth or on the surface.... It is from this variety that the Venetians makechrysocolla, which I callborax.... The second variety of artificialnitrumis made at the present day from the nativenitrum, called by the Arabstincar, but I call it usually by the Greek namechrysocolla; it is really the Arabicborax.... Thisnitrumdoes not decrepitate nor fly out of the fire; however, the native variety swells up from within." The application of the wordchrysocolla(chrysos, gold;colla, solder) to soldering materials, and at the same time to the copper mineral, is of Greek origin. If any further proof were needed as to the substance meant by Agricola, it lies in the wordtincar. For a long time the borax of Europe was imported from Central Asia, through Constantinople and Venice, under the name oftincalortincar. When this trade began, we do not know; evidently before Agricola's time. The statement here of making borax from alum and sal-ammoniac is identical with the assertion of Biringuccio (II., 9).Sal-ammoniac.—The early history of this—ammonium chloride—is also under a cloud. Pliny (XXXI., 39) speaks of asal-hammoniacum, and Dioscorides (V., 85) uses much the same word. Pliny describes it as from near the temple of Ammon in Egypt. None of the distinctive characteristics of sal-ammoniac are mentioned, and there is every reason to believe it was either common salt or soda. Herodotus, Strabo, and others mention common salt sent from about the same locality. The first authentic mention is in Geber, who calls itsal-ammoniacum, and describes a method of making, and several characteristic reactions. It was known in the Middle Ages under various names, among themsal-aremonicum. Agricola (De Nat. Fos.,III., p. 206) notes its characteristic quality of volatilization. "Sal-ammoniac ... in the fire neither crackles nor flies out, but is totally consumed." He also says (p. 208): "Borax is used by goldsmiths to solder gold, likewise silver. The artificers who make iron needles (tacks?) similarly use sal-ammoniac when they cover the heads with tin." The statement from Pliny mentioned in this paragraph is fromXXXIII., 29, where he describes thechrysocollaused as gold solder as made from verdigris,nitrum, and urine in the way quoted. It is quite possible that this solder was sal-ammoniac, though not made in quite this manner. Pliny refers in several places (XXXIII., 26, 27, 28, and 29,XXXV., 28, etc.) tochrysocolla, about which he is greatly confused as between gold-solder, the copper mineral, and a green pigment, the latter being of either mineral origin.[Pg 561][9]Saltpetre was secured in the Middle Ages in two ways, but mostly from the treatment of calcium nitrate efflorescence on cellar and similar walls, and from so-called saltpetre plantations. In this description of the latter, one of the most essential factors is omitted until the last sentence,i.e., that the nitrous earth was the result of the decay of organic or animal matter over a long period. Such decomposition, in the presence of potassium and calcium carbonates—the lye and lime—form potassium and calcium nitrates, together with some magnesium and sodium nitrates. After lixiviation, the addition of lye converts the calcium and magnesium nitrates into saltpetre,i.e., Ca(NO3)2+ K2CO3= CaCO3+ 2KNO3. The carbonates precipitate out, leaving the saltpetre in solution, from which it was evaporated and crystallized out. The addition of alum as mentioned would scarcely improve the situation.The purification by repeated re-solution and addition of lye, and filtration, would eliminate the remaining other salts. The purification with sulphur, however, is more difficult[Pg 562]to understand. In this case the saltpetre is melted and the sulphur added and set alight. Such an addition to saltpetre would no doubt burn brilliantly. The potassium sulphate formed would possibly settle to the bottom, and if the "greasy matter" were simply organic impurities, they might be burned off. This method of refining appears to have been copied from Biringuccio (X., 1), who states it in almost identical terms.Historical Note.—As mentioned inNote 6 above, it is quite possible that the Ancients did include efflorescence of walls undernitrum; but, so far as we are aware, no specific mention of such an occurrence ofnitrumis given, and, as stated before, there is every reason to believe that all the substances under that term were soda and potash. Especially the frequent mention of the preparation ofnitrumby way of burning, argues strongly against saltpetre being included, as they would hardly have failed to notice the decrepitation. Argument has been put forward that Greek fire contained saltpetre, but it amounts to nothing more than argument, for in those receipts preserved, no salt of any kind is mentioned. It is most likely that the leprosy of house-walls of the Mosaic code (LeviticusXIV., 34 to 53) was saltpetre efflorescence. The drastic treatment by way of destruction of such "unclean" walls and houses, however, is sufficient evidence that this salt was not used. The first certain mention of saltpetre (sal petrae) is in Geber. As stated before, the date of this work is uncertain; in any event it was probably as early as the 13th Century. He describes the making of "solvative water" with alum and saltpetre, so there can be no doubt as to the substance (see Note on p.460, on nitric acid). There is also a work by a nebulous Marcus Graecus, where the wordsal petrosumis used. And it appears that Roger Bacon (died 1294) and Albertus Magnus (died 1280) both had access to that work. Bacon uses the termsal petraefrequently enough, and was the first to describe gunpowder (De Mirabili Potestate Artis et Naturae1242). He gives no mention of the method of making hissal petrae. Agricola uses throughout the Latin text the termhalinitrum, a word he appears to have coined himself. However, he gives its German equivalent in theInterpretatioassalpeter. The only previous description of the method of making saltpetre, of which we are aware, is that of Biringuccio (1540), who mentions the boiling of the excrescences from walls, and also says a good deal about boiling solutions from "nitrous" earth, which may or may not be of "plantation" origin. He also gives this same method of refining with sulphur. In any event, this statement by Agricola is the first clear and complete description of the saltpetre "plantations." Saltpetre was in great demand in the Middle Ages for the manufacture of gunpowder, and the first record of that substance and of explosive weapons necessarily involves the knowledge of saltpetre. However, authentic mention of such weapons only begins early in the 14th Century. Among the earliest is an authority to the Council of Twelve at Florence to appoint persons to make cannon, etc., (1326), references to cannon in the stores of the Tower of London, 1388, &c.[Pg 564][10]There are three methods of manufacturing alum described by Agricola, the first and third apparently from shales, and the second from alum rock or "alunite." The reasons for assuming that the first process was from shales, are the reference to the "aluminous earth" as ore (venae) coming from "veins," and also the mixture of vitriol. In this process the free sulphuric acid formed by the oxidation of pyrites reacts upon the argillaceous material to form aluminium sulphate. The decomposed ore is then placed in tanks and lixiviated. The solution would contain aluminium sulphate, vitriol, and other impurities. By the addition of urine, the aluminium sulphate would be converted into ammonia alum. Agricola is, of course, mistaken as to the effect of the addition, being under the belief that it separated the vitriol from the alum; in fact, this belief was general until the latter part of the 18th Century, when Lavoisier determined that alum must have an alkali base. Nor is it clear[Pg 565]from this description exactly how they were separated. In a condensed solution allowed to cool, the alum would precipitate out as "alum meal," and the vitriol would "float on top"—in solution. The reference to "meal" may represent this phenomenon, and the re-boiling referred to would be the normal method of purification by crystallization. The "asbestos" and gypsum deposited in the caldrons were no doubt feathery and mealy calcium sulphate. The alum produced would, in any event, be mostly ammonia alum.The second process is certainly the manufacture from "alum rock" or "alunite" (the hydrous sulphate of aluminium and potassium), such as that mined at La Tolfa in the Papal States, where the process has been for centuries identical with that here described. The alum there produced is the double basic potassium alum, and crystallizes into cubes instead of octahedra,i.e., the Roman alum of commerce. The presence of much ferric oxide gives the rose colour referred to by Agricola. This account is almost identical with that of Biringuccio (II., 4), and it appears from similarity of details that Agricola, as stated in hispreface, must have "refreshed his mind" from this description; it would also appear from theprefacethat he had himself visited the locality.The third process is essentially the same as the first, except that the decomposition of the pyrites was hastened by roasting. The following obscure statement of some interest occurs in Agricola'sDe Natura Fossilium, p. 209:—"... alum is made from vitriol, for when oil is made from the latter, alum is distilled out (expirat). This absorbs the clay which is used in cementing glass, and when the operation is complete the clay is macerated with pure water, and the alum is soon afterward deposited in the shape of small cubes." Assuming the oil of vitriol to be sulphuric acid and the clay "used in cementing glass" to be kaolin, we have here the first suggestion of a method for producing alum which came into use long after."Burnt alum" (alumen coctum).—Agricola frequently uses this expression, and on p.568, describes the operation, and the substance is apparently the same as modern dehydrated alum, often referred to as "burnt alum."Historical Notes.—Whether the Ancients knew of alum in the modern sense is a most vexed question. The Greeks refer to a certain substance asstypteria, and the Romans refer to this same substance asalumen. There can be no question as to their knowledge and common use of vitriol, nor that substances which they believed were entirely different from vitriol were comprised under the above names. Beckmann (Hist. of Inventions, Vol.I., p. 181) seems to have been the founder of the doctrine that the ancientalumenwas vitriol, and scores of authorities seem to have adopted his arguments without inquiry, until that belief[Pg 566]is now general. One of the strongest reasons put forward was that alum does not occur native in appreciable quantities. Apart from the fact that the weight of this argument has been lost by the discovery that alum does occur in nature to some extent as an aftermath of volcanic action, and as an efflorescence from argillaceous rocks, we see no reason why the Ancients may not have prepared it artificially. One of the earliest mentions of such a substance is by Herodotus (II., 180) of a thousand talents ofstypteria, sent by Amasis from Egypt as a contribution to the rebuilding of the temple of Delphi. Diodorus (V., 1) mentions the abundance which was secured from the Lipari Islands (Stromboli, etc.), and a small quantity from the Isle of Melos. Dioscorides (V., 82) mentions Egypt, Lipari Islands, Melos, Sardinia, Armenia, etc., "and generally in any other places where one finds red ochre (rubrica)." Pliny (XXXV., 52) gives these same localities, and is more explicit as to how it originates—"from an earthy water which exudes from the earth." Of these localities, the Lipari Islands (Stromboli, etc.), and Melos are volcanic enough, and both Lipari and Melos are now known to produce natural alum (Dana. Syst. Min., p. 95; and Tournefort, "Relation d'un voyage du Levant." London, 1717,LettreIV., Vol. 1.). Further, the hair-like alum of Dioscorides, repeated by Pliny below, was quite conceivably fibrouskalinite, native potash alum, which occurs commonly as an efflorescence. Be the question of native alum as it may—and vitriol is not much more common—our own view that the ancientalumenwas alum, is equally based upon the artificial product. Before entering upon the subject, we consider it desirable to set out the properties of the ancient substance, a complete review of which is given by Pliny (XXXV., 52), he obviously quoting also from Dioscorides, which, therefore, we do not need to reproduce. Pliny says:—"Not less important, or indeed dissimilar, are the uses made ofalumen; by which name is understood a sort of salty earth. Of this, there are several kinds. In Cyprus there is a whitealumen, and a darker kind. There is not a great difference in their colour, though the uses made of them are very dissimilar,—the whitealumenbeing employed in a liquid state for dyeing wool bright colours, and the dark-colouredalumen, on the other hand, for giving wool a sombre tint. Gold is purified with blackalumen. Every kind ofalumenis from alimuswater which exudes from the earth. The collection of it commences in winter, and it is dried by the summer sun. That portion of it which first matures is the whitest. It is obtained in Spain, Egypt, Armenia, Macedonia, Pontus, Africa, and the islands of Sardinia, Melos, Lipari, and Strongyle; the most esteemed, however, is that of Egypt, the next best from Melos. Of this last there are two kinds, the liquidalumen, and the solid. Liquidalumen, to be good, should be of a limpid and milky appearance; when[Pg 568]rubbed, it should be without roughness, and should give a little heat. This is calledphorimon. The mode of detecting whether it has been adulterated is by pomegranate juice, for, if genuine, the mixture turns black. The other, or solid, is pale and rough and turns dark with nut-galls; for which reason it is calledparaphoron. Liquidalumenis naturally astringent, indurative, and corrosive; used in combination with honey, it heals ulcerations.... There is one kind of solidalumen, called by the Greeksschistos, which splits into filaments of a whitish colour; for which reason some prefer calling ittrichitis(hair like).Alumenis produced from the stonechalcitis, from which copper is also made, being a sort of coagulated scum from that stone. This kind ofalumenis less astringent than the others, and is less useful as a check upon bad humours of the body.... The mode of preparing it is to cook it in a pan until it has ceased being a liquid. There is another variety ofalumenalso, of a less active nature, calledstrongyle. It is of two kinds. The fungous, which easily dissolves, is utterly condemned. The better kind is the pumice-like kind, full of small holes like a sponge, and is in round pieces, more nearly white in colour, somewhat greasy, free from grit, friable, and does not stain black. This last kind is cooked by itself upon charcoal until it is reduced to pure ashes. The best kind of all is that calledmelinum, from the Isle of Melos, as I have said, none being more effectual as an astringent, for staining black, and for indurating, and none becomes more dry.... Above all other properties ofalumenis its remarkable astringency, whence its Greek name.... It is injected for dysentry and employed as a gargle." The lines omitted refer entirely to medical matters which have no bearing here. The following paragraph (often overlooked) from Pliny (XXXV., 42) also has an important bearing upon the subject:—"In Egypt they employ a wonderful method of dyeing. The white cloth, after it is pressed, is stained in various places, not with dye stuffs, but with substances which absorb colours. These applications are not apparent on the cloth, but when it is immersed in a caldron of hot dye it is removed the next moment brightly coloured. The remarkable circumstance is that although there be only one dye in the caldron yet different colours appear in the cloth."It is obvious from Pliny's description above, and also from the making of vitriol (seeNote 11, p. 572), that this substance was obtained from liquor resulting from natural or artificial lixiviation of rocks—in the case of vitriols undoubtedly the result of decomposition of pyritiferous rocks (such aschalcitis). Such liquors are bound to contain aluminum sulphate if there is any earth or clay about, and whether they contained alum would be a question of an alkali being present. If no alkali were present in this liquor, vitriol would[Pg 569]crystallize out first, and subsequent condensation would yield aluminum sulphate. If alkali were present, the alum would crystallize out either before or with the vitriol. Pliny's remark, "that portion of it which first matures is whitest", agrees well enough with this hypothesis. No one will doubt that some of the properties mentioned above belong peculiarly to vitriol, but equally convincing are properties and uses that belong to alum alone. The strongly astringent taste, white colour, and injection for dysentry, are more peculiar to alum than to vitriol. But above all other properties is that displayed in dyeing, for certainly if we read this last quotation from Pliny in conjunction with the statement that whitealumenproduces bright colours and the dark kind, sombre colours, we have the exact reactions of alum and vitriol when used as mordants. Therefore, our view is that the ancient salt of this character was a more or less impure mixture ranging from alum to vitriol—"the whiter the better." Further, considering the ancient knowledge of soda (nitrum), and the habit of mixing it into almost everything, it does not require much flight of imagination to conceive its admixture to the "water," and the absolute production of alum.Whatever may have been the confusion between alum and vitriol among the Ancients, it appears that by the time of the works attributed to Geber (12th or 13th Century), the difference was well known. His work (Investigationes perfectiones,IV.) refers toalumen glacialeandalumen jamenias distinguished from vitriol, and gives characteristic reactions which can leave no doubt as to the distinction. We may remark here that the repeated statement apparently arising from Meyer (History of Chemistry, p. 51) that Geber used the termalum de roccais untrue, this term not appearing in the early Latin translations. During the 15th Century alum did come to be known in Europe asalum de rocca. Various attempts have been made to explain the origin of this term, ranging from the Italian root, a "rock," to the town of Rocca in Syria, where alum was supposed to have been produced. In any event, the supply for a long period prior to the middle of the 15th Century came from Turkey, and the origin of the methods of manufacture described by Agricola, and used down to the present day, must have come from the Orient.In the early part of the 15th Century, a large trade in alum was done between Italy and Asia Minor, and eventually various Italians established themselves near Constantinople and Smyrna for its manufacture (Dudae,Historia Byzantina Venetia, 1729, p. 71). The alum was secured by burning the rock, and lixiviation. With the capture of Constantinople by the Turks (1453), great feeling grew up in Italy over the necessity of buying this requisite for their dyeing establishments from the infidel, and considerable exertion was made to find other sources of supply. Some minor works were attempted, but nothing much[Pg 570]eventuated until the appearance of one John de Castro. From the Commentaries of Pope PiusII.(1614, p. 185), it appears that this Italian had been engaged in dyeing cloth in Constantinople, and thus became aware of the methods of making alum. Driven out of that city through its capture by the Turks, he returned to Italy and obtained an office under the Apostolic Chamber. While in this occupation he discovered a rock at Tolfa which appeared to him identical with that used at Constantinople in alum manufacture. After experimental work, he sought the aid of the Pope, which he obtained after much vicissitude. Experts were sent, who after examination "shed tears of joy, they kneeling down three times, worshipped God and praised His kindness in conferring such a gift on their age." Castro was rewarded, and the great papal monopoly was gradually built upon this discovery. The industry firmly established at Tolfa exists to the present day, and is the source of the Roman alum of commerce. The Pope maintained this monopoly strenuously, by fair means and by excommunication, gradually advancing the price until the consumers had greater complaint than against the Turks. The history of the disputes arising over the papal alum monopoly would alone fill a volume.By the middle of the 15th Century alum was being made in Spain, Holland, and Germany, and later in England. In her efforts to encourage home industries and escape the tribute to the Pope, Elizabeth (see Note on p.283) invited over "certain foreign chymistes and mineral masters" and gave them special grants to induce them to "settle in these realmes." Among them was Cornelius Devoz, to whom was granted the privilege of "mining and digging in our Realm of England for allom and copperas." What Devoz accomplished is not recorded, but the first alum manufacture on a considerable scale seems to have been in Yorkshire, by one Thomas Chaloner (about 1608), who was supposed to have seduced workmen from the Pope's alum works at Tolfa, for which he was duly cursed with all the weight of the Pope and Church. (Pennant, Tour of Scotland, 1786).[Pg 572][11]The term for vitriol used by the Roman authors, followed by Agricola, isatramentum sutorium, literally shoemaker's blacking, the term no doubt arising from its ancient (and modern) use for blackening leather. The Greek term waschalcanthon. The term "vitriol" seems first to appear in Albertus Magnus (De Mineralibus,LiberV.), who died in 1280, where he uses the expression "atramentum viride a quibusdam vitreolum vocatur." Agricola (De Nat. Foss., p. 213) states, "In recent years the namevitriolumhas been given to it." The first adequate description of vitriol is by Dioscorides (V., 76), as follows:—"Vitriol (chalcanthon) is of one genus, and is a solidified liquid, but it has three different species. One is formed from the liquids which trickle down drop by drop and congeal in certain mines; therefore those who work in the Cyprian mines call itstalactis. Petesius calls this kindpinarion. The second kind is that which collects in certain caverns; afterward it is poured into trenches, where it congeals, whence it derives its namepēctos. The third kind is calledhephthonand is mostly made in Spain; it has a beautiful colour but is weak. The manner of preparing it is as follows: dissolving it in water, they boil it, and then they transfer it to cisterns and leave it to settle. After a certain number of days it congeals and separates into many small pieces, having the form of dice, which stick together like grapes. The most valued is blue, heavy, dense, and translucent." Pliny (XXXIV., 32) says:—"By the name which they have given to it, the Greeks indicate the similar nature of copper andatramentum sutorium, for they call itchalcanthon. There is no substance of an equally miraculous nature. It is made in Spain from wells of this kind of water. This water is boiled with an equal quantity of pure water, and is then poured into wooden tanks (fish ponds). Across these tanks there are fixed beams, to which hang cords stretched by little stones. Upon these cords adheres thelimus(Agricola's 'juice') in drops of a vitreous appearance, somewhat resembling a bunch of grapes. After removal, it is dried for thirty days. It is of a blue colour, and of a brilliant lustre, and is very like glass. Its solution is the blacking used for colouring leather.Chalcanthonis made in many other ways: its kind of earth is sometimes dug from ditches, from the sides of which exude drops, which solidify by the winter frosts into icicles, calledstalagmia, and there is none more pure. When its colour is nearly white, with a slight tinge of violet, it is calledleukoïon. It is also made in rock basins, the rain water collecting thelimusinto them, where it becomes hardened. It is also made in the same way as salt by the intense heat of the sun. Hence it is that some distinguish two kinds, the mineral and the artificial; the latter being paler than the former and as much inferior to it in quality as it is in colour."While Pliny gives prominence to blue vitriol, his solution for colouring leather must have been the iron sulphate. There can be no doubt from the above, however, that both iron and copper sulphates were known to the Ancients. From the methods for making vitriol given here inDe Re Metallica, it is evident that only the iron sulphate would be produced, for the introduction of iron strips into the vats would effectually precipitate any copper. It is our belief that generally throughout this work, the iron sulphate is meant by the termatramentum sutorium. InDe Natura Fossilium(p. 213-15) Agricola gives three varieties ofatramentum sutorium,—viride,caeruleum, andcandidum,i.e., green, blue, and white. Thus the first mention of white vitriol (zinc sulphate) appears to be due to him, and he states further (p. 213): "A white sort is found, especially at Goslar, in the shape of icicles, transparent like crystals." And on p. 215: "Since I have explained the nature of vitriol and its relatives, which are obtained from cupriferous pyrites, I will next speak of an acrid solidified juice which commonly comes fromcadmia. It is found at Annaberg in the tunnel driven to the Saint Otto mine; it is hard and white, and so acrid that it kills mice, crickets, and every kind of animal. However, that feathery substance which oozes out from the mountain rocks and the thick substance found hanging in tunnels and caves from which saltpetre is made, while frequently acrid, does not come fromcadmia." Dana (Syst. of Min., p. 939) identifies this asGoslarite—native zinc sulphate. It does not appear, however, that artificial zinc vitriol was made in Agricola's time. Schlüter (Huette-Werken, Braunschweig 1738, p. 597) states it to have been made for the first time at Rammelsberg about 1570.[Pg 573]It is desirable here to enquire into the nature of the substances given by all of the old mineralogists under the Latinized Greek termschalcitis,misy,sory, andmelanteria. The first mention of these minerals is in Dioscorides, who (V., 75-77) says: "The bestchalcitisis like copper. It is friable, not stony, and is intersected by long brilliant veins....Misyis obtained from Cyprus; it should have the appearance of gold, be hard, and when pulverised it should have the colour of gold and sparkle like stars. It has the same properties aschalcitis.... The best is from Egypt.... One kind ofmelanteriacongeals like salt in the entries to copper mines. The other kind is earthy and appears on the surface of the aforesaid mines. It is found in the mines of Cilicia and other regions. The best has the colour of sulphur, is smooth, pure, homogenous, and upon contact with water immediately becomes black.... Those who considersoryto be the same asmelanteria, err greatly.Soryis a species of its own, though it is not dissimilar. The smell ofsoryis oppressive and provokes nausea. It is found in Egypt and in other regions, as Libya, Spain, and Cyprus. The best is from Egypt, and when broken is black, porous, greasy, and astringent." Pliny (XXXIV., 29-31) says:—"That is calledchalcitisfrom which, as well as itself copper (?) is extracted by heat. It differs fromcadmiain that this is obtained from rocks near the surface, while that is taken from rocks below the surface. Alsochalcitisis immediately friable, being naturally so soft as to appear like compressed wool. There is also this other distinction;chalcitiscontains three other substances, copper,misy, andsory. Of each of these we shall speak in their appropriate places. It contains elongated copper veins. The most approved kind is of the colour of honey; it is streaked with fine sinuous veins and is friable and not stony. It is considered most valuable when fresh.... Thesoryof Egypt is the most esteemed, being much superior to that of Cyprus, Spain, and Africa; although some prefer thesoryfrom Cyprus for affections of the eyes. But from whatever nation it comes, the best is that which has the strongest odour, and which, when ground up, becomes greasy, black, and spongy. It is a substance so unpleasant to the stomach that some persons are nauseated by its smell. Some say thatmisyis made by the burning of stones in trenches, its fine yellow powder being mixed with the ashes of pine-wood. The truth is, as I said above, that though obtained from the stone, it is already made and in solid masses, which require force to detach them. The best comes from the works of Cyprus, its characteristics being that when broken it sparkles like gold, and when ground it presents a sandy appearance, but on the contrary, if heated, it is similar tochalcitis.Misyis used in refining gold...."Agricola's views on the subject appear inDe Natura Fossilium. He says (p. 212):—"The cupriferous pyrites (pyrites aerosus) calledchalcitisis the mother and cause ofsory—which is likewise known as minevitriol(atramentum metallicum)—andmelanteria. These in turn yield vitriol and such related things. This may be seen especially at Goslar, where the nodular lumps of dark grey colour are called vitriol stone (lapis atramenti). In the centre of them is found greyish pyrites, almost dissolved, the size of a walnut. It is enclosed on all sides, sometimes bysory, sometimes bymelanteria. From them start little veinlets of greenish vitriol which spread all over it, presenting somewhat the appearance of hairs extending in all directions and cohering together.... There are five species of this solidified juice,melanteria,sory,chalcitis,misy, and vitriol. Sometimes many are found in one place, sometimes all of them, for one originates from the other. From pyrites, which is, as one might say, the root of all these juices, originates the above-mentionedsoryandmelanteria. Fromsory,chalcitis, andmelanteriaoriginate the various kinds of vitriol....Sory,melanteria,chalcitis, andmisyare always native; vitriol alone is either native or artificial. From them vitriol effloresces white, and sometimes green or blue.Misyeffloresces not only fromsory,melanteria, andchalcitis, but also from all the vitriols, artificial as well as natural....Soryandmelanteriadiffer somewhat from the others, but they are of the same colours, grey and black; butchalcitisis red and copper-coloured;misyis yellow or gold-coloured. All these native varieties have the odour of lightning (brimstone), butsoryis the most powerful. The feathery vitriol is soft and fine and hair-like, andmelanteriahas the appearance of wool and it has a similarity to salt; all these are rare and light;sory,chalcitis, andmisyhave the following relations.Sorybecause of its density has the hardness of stone, although its texture is very coarse.Misyhas a very fine texture.Chalcitisis between the two; because of its roughness and strong odour it differs frommelanteria, although they do not differ in colour. The vitriols, whether natural or artificial, are hard and dense ... as regarding shape,sory,chalcitis,misy, andmelanteriaare nodular, butsoryis occasionally porous, which is peculiar to it.[Pg 574]Misywhen it effloresces in no great quantity from the others is like a kind of pollen, otherwise it is nodular.Melanteriasometimes resembles wool, sometimes salt."The sum and substance, therefore, appears to be thatmisyis a yellowish material, possibly ochre, andsorya blackish stone, both impregnated with vitriol.Chalcitisis a partially decomposed pyrites; andmelanteriais no doubt native vitriol. From this last term comes the modernmelanterite, native hydrous ferrous sulphate. Dana (System of Mineralogy, p. 964) considersmisyto be in partcopiapite—basic ferric sulphate—but any such part would not come under Agricola's objection to it as a source of vitriol. The disabilities of this andchalcitismay, however, be due to their copper content.[Pg 578][12]Agricola (De Nat. Fos., 221) says:—"There is a species of artificial sulphur made from sulphur and iron hammer-scales, melted together and poured into moulds. This, because it heals scabs of horses, is generally calledcaballinum." It is difficult to believe such a combination was other than iron sulphide, but it is equally difficult to understand how it was serviceable for this purpose.[13]Inasmuch as pyrites is discussed in the next paragraph, the material of the first distillation appears to be native sulphur. Until the receiving pots became heated above the melting point of the sulphur, the product would be "flowers of sulphur," and not the wax-like[Pg 579]product. The equipment described for pyrites in the next paragraph would be obviously useful only for coarse material.But little can be said on the history of sulphur; it is mentioned often enough in the Bible and also by Homer (Od.XXII., 481). The Greeks apparently knew how to refine it, although neither Dioscorides nor Pliny specifically describes such an operation. Agricola says (De Nat. Fos., 220): "Sulphur is of two kinds; the mineral, which the Latins callvivum, and the Greeksapyron, which means 'not exposed to the fire' (ignem non expertum) as rightly interpreted by Celsius; and the artificial, called by the Greekspepyromenon, that is, 'exposed to the fire.'" InBook X., the expressionsulfur ignem non expertumfrequently appears, no doubt in Agricola's mind for native sulphur, although it is quite possible that the Greek distinction was between "flowers" of sulphur and the "wax-like" variety.[Pg 581][14]The substances referred to under the namesbitumen,asphalt,maltha,naphtha,petroleum,rock-oil, etc., have been known and used from most ancient times, and much of our modern nomenclature is of actual Greek and Roman ancestry. These peoples distinguished three related substances,—the Greekasphaltosand Romanbitumenfor the hard material,—Greekpissasphaltosand Romanmalthafor the viscous, pitchy variety—and occasionally the Greeknaphthaand Romannaphthafor petroleum proper, although it is often enough referred to as liquidbitumenor liquidasphaltos. The termpetroleumapparently first appears in Agricola'sDe Natura Fossilium(p. 222), where he says the "oil of bitumen ... now[Pg 582]calledpetroleum." Bitumen was used by the Egyptians for embalming from pre-historic times,i.e., prior to 5000B.C., the term "mummy" arising from the Persian word for bitumen,mumiai. It is mentioned in the tribute from Babylonia to ThotmesIII., who lived about 1500B.C.(Wilkinson, Ancient EgyptiansI., p. 397). The Egyptians, however, did not need to go further afield than the Sinai Peninsula for abundant supplies. Bitumen is often cited as the real meaning of the "slime" mentioned in Genesis (XI., 3;XIV., 10), and used in building the Tower of Babel. There is no particular reason for this assumption, except the general association of Babel, Babylon, and Bitumen. However, the Hebrew wordsiftfor pitch or bitumen does occur as the cement used for Moses's bulrush cradle (ExodusII., 3), and Moses is generally accounted about 1300B.C.Other attempts to connect Biblical reference to petroleum and bitumen revolve around JobXXIX., 6, Deut.XXXII., 13, MaccabeesII.,I, 18, MatthewV., 13, but all require an unnecessary strain on the imagination.The plentiful occurrence of bitumen throughout Asia Minor, and particularly in the Valley of the Euphrates and in Persia, is the subject of innumerable references by writers from Herodotus (484-424B.C.) down to the author of the company prospectus of recent months. Herodotus (I., 179) and Diodorus Siculus (I) state that the walls of Babylon were mortared with bitumen—a fact partially corroborated by modern investigation. The following[Pg 583]statement by Herodotus (VI., 119) is probably the source from which Pliny drew the information which Agricola quotes above. In referring to a well at Ardericca, a place about 40 miles from ancient Susa, in Persia, Herodotus says:—"For from the well they get bitumen, salt, and oil, procuring it in the way that I will now describe: they draw with a swipe, and instead of a bucket they make use of the half of a wine-skin; with this the man dips and, after drawing, pours the liquid into a reservoir, wherefrom it passes into another, and there takes three different shapes. The salt and bitumen forthwith collect and harden, while the oil is drawn off into casks. It is called by the Persiansrhadinace, is black, and has an unpleasant smell." (Rawlinson's Trans.III., p. 409). The statement from Pliny (XXXI., 39) here referred to by Agricola, reads:—"It (salt) is made from water of wells poured into salt-pans. At Babylon the first condensed is a bituminous liquid like oil which is burned in lamps. When this is taken off, salt is found beneath. In Cappadocia also the water from both wells and springs is poured into salt-pans." When petroleum began to be used as an illuminant it is impossible to say. A passage in Aristotle'sDe Mirabilibus(127) is often quoted, but in reality it refers only to a burning spring, a phenomenon noted by many writers, but from which to its practical use is not a great step. The first really definite statement as to the use of petroleum as an[Pg 584]illuminant is Strabo's quotation (XVI., 1, 15) from Posidonius: "Asphaltus is found in great abundance in Babylonia. Eratosthenes describes it as follows:—The liquidasphaltus, which is callednaphtha, is found in Susa; the dry kind, which can be made solid, in Babylonia. There is a spring of it near the Euphrates.... Others say that the liquid kind is also found in Babylonia.... The liquid kind, callednaphtha, is of a singular nature. When it is brought near the fire, the fire catches it.... Posidonius says that there are springs ofnaphthain Babylonia, some of which produce white, others blacknaphtha; the first of these, I mean whitenaphtha, which attracts flame, is liquid sulphur; the second or blacknaphthais liquidasphaltus, and is burnt in lamps instead of oil." (Hamilton's Translation, Vol.III., p. 151). Eratosthenes lived about 200B.C., and Posidonius about 100 years later. Dioscorides (I., 83), after discussing the usual sources of bitumen says: "It is found in a liquid state in Agrigentum in Sicily, flowing on streams; they use it for lights in lanterns in place of oil. Those who call the Sicilian kind oil are under a delusion, for it is agreed that it is a kind of liquid bitumen." Pliny adds nothing much new to the above quotations, except in regard to these same springs (XXXV., 51) that "The inhabitants collect it on the panicles of reeds, to which it quickly adheres and they use it for burning in lamps instead of oil." Agricola (De Natura Fossilium, BookIV.) classifies petroleum, coal, jet, and obsidian, camphor, and amber as varieties of bitumen, and devotes much space to the refutation of the claims that the last two are of vegetable origin.[15]Agricola (De Natura Fossilium, p. 215) in discussing substances which originate from copper, gives among them greenchrysocolla(as distinguished from borax, etc., seeNote 8 above), and says: "Nativechrysocollaoriginates in veins and veinlets, and is found mostly by itself like sand, or adhering to metallic substances, and when scraped off from this appears similar to its own sand. Occasionally it is so thin that very little can be scraped off. Or else it occurs in waters which, as I have said, wash these minerals, and afterward it settles as a powder. At Neusohl in the Carpathians, green water flowing from an ancient tunnel wears away thischrysocollawith it. The water is collected in thirty large reservoirs, where it deposits thechrysocollaas a sediment, which they collect every year and sell,"—as a pigment. This description of its occurrence would apply equally well to modernchrysocollaor to malachite. The solution from copper ores would deposit some sort of green incrustation, of carbonates mostly.[Pg 585][16]The statement in Pliny (XXXVI., 66) to which Agricola refers is as follows: "Then as ingenuity was not content with the mixing ofnitrum, they began the addition oflapis[Pg 586]magnes, because of the belief that it attracts liquefied glass as well as iron. In a similar manner many kinds of brilliant stones began to be added to the melting, and then shells and fossil sand. Authors tell us that the glass of India is made of broken crystal, and in consequence nothing can compare with it. Light and dry wood is used for fusing,cyprium(copper?) andnitrumbeing added, particularlynitrumfrom Ophir etc."A great deal of discussion has arisen over this passage, in connection with what thislapis magnesreally was. Pliny (XXXVI., 25) describes the lodestone under this term, but also says: "There (in Ethiopia) also ishaematites magnes, a stone of blood colour, which shows a red colour if crushed, or of saffron. Thehaematiteshas not the same property of attracting iron asmagnes." Relying upon this sentence for an exception to the ordinary sort ofmagnes, and upon the impossible chemical reaction involved, most commentators have endeavoured to show that lodestone was not the substance meant by Pliny, but manganese, and thus they find here the first knowledge of this mineral. There can be little doubt that Pliny assumed it to be the lodestone, and Agricola also. Whether the latter had any independent knowledge on this point in glass-making or was merely quoting Pliny—which seems probable—we do not know. In any event, Biringuccio, whose work precededDe Re Metallicaby fifteen years, does definitely mention manganese in this connection. He dismisses this statement of Pliny with the remark (p. 37-38): "The Ancients wrote about lodestones, as Pliny states, and they mixed it together withnitrumin their first efforts to make glass." The following passage from this author (p. 36-37), however, is not only of interest in this connection, but also as possibly being the first specific mention of manganese under its own name. Moreover, it has been generally overlooked in the many discussions of the subject. "Of a similar nature (tozaffir) is also another mineral calledmanganese, which is found, besides in Germany, at the mountain of Viterbo in Tuscany ... it is the colour offerrigno scuro(iron slag?). In melting it one cannot obtain any metal ... but it gives a very fine colour to glass, so that the glass workers use it in their pigments to secure an azure colour.... It also has such a property that when put into melted glass it cleanses it and makes it white, even if it were green or yellow. In a hot fire it goes off in a vapour like lead, and turns into ashes."To enter competently into the discussion of the early history of glass-making would employ more space than can be given, and would lead but to a sterile end. It is certain that the art was pre-Grecian, and that the Egyptians were possessed of some knowledge of making and blowing it in the XI Dynasty (according to Petrie 3,500B.C.), the wall painting at Beni Hassen, which represents glass-blowing, being attributed to that period. The remains of a glass factory at Tel el Amarna are believed to be of the XVIII Dynasty. (Petrie, 1,500B.C.). The art reached a very high state of development among the Greeks and Romans. No discussion of this subject omits Pliny's well-known story (XXXVI, 65), which we also add: "The tradition is that a merchant ship laden withnitrumbeing moored at this place, the merchants were preparing their meal on the beach, and not having stones to prop up their pots, they used lumps ofnitrumfrom the ship, which fused and mixed with the sands of the shore, and there flowed streams of a new translucent liquid, and thus was the origin of glass."
[Pg 546][1]The history of salt-making in salt-pans, from sea-water or salt springs, goes further back than human records. From an historical point of view the real interest attached to salt lies in the bearing which localities rich in either natural salt or salt springs, have had upon the movements of the human race. Many ancient trade routes have been due to them, and innumerable battles have been fought for their possession. Salt has at times served for currency, and during many centuries in nearly every country has served as a basis of taxation. These subjects do not, however, come within the scope of this text. For the quotation from Pliny referred to, seeNote 14 below, on bitumen.
[Pg 546][1]The history of salt-making in salt-pans, from sea-water or salt springs, goes further back than human records. From an historical point of view the real interest attached to salt lies in the bearing which localities rich in either natural salt or salt springs, have had upon the movements of the human race. Many ancient trade routes have been due to them, and innumerable battles have been fought for their possession. Salt has at times served for currency, and during many centuries in nearly every country has served as a basis of taxation. These subjects do not, however, come within the scope of this text. For the quotation from Pliny referred to, seeNote 14 below, on bitumen.
[2]The first edition givesgraviorem, the latter editionsgratiorem, which latter would have quite the reverse meaning from the above.
[2]The first edition givesgraviorem, the latter editionsgratiorem, which latter would have quite the reverse meaning from the above.
[Pg 550][3]The following are approximately the English equivalents:—Pints.Quarts.Gallons.1Cyathus.083Cyathi=1Quartarius.244Quartarii=1Sextarius.996Sextarii=1Congius5.942.9716Sextarii=1Modius15.857.931.988Congii=1Amphora47.5723.785.94The dipper mentioned would thus hold about one and one quarter gallons, and the cask ten gallons.
[Pg 550][3]The following are approximately the English equivalents:—
Pints.Quarts.Gallons.1Cyathus.083Cyathi=1Quartarius.244Quartarii=1Sextarius.996Sextarii=1Congius5.942.9716Sextarii=1Modius15.857.931.988Congii=1Amphora47.5723.785.94
The dipper mentioned would thus hold about one and one quarter gallons, and the cask ten gallons.
[Pg 552][4]The salt industry, founded upon salt springs, is still of importance to this city. It was a salt centre of importance to the Germanic tribes before Charles, the son of Charlemagne, erected a fortress here in 806. Mention of the salt works is made in the charter by Otto I., conveying the place to the Diocese of Magdeburg, in 968.
[Pg 552][4]The salt industry, founded upon salt springs, is still of importance to this city. It was a salt centre of importance to the Germanic tribes before Charles, the son of Charlemagne, erected a fortress here in 806. Mention of the salt works is made in the charter by Otto I., conveying the place to the Diocese of Magdeburg, in 968.
[Pg 558][5]PlinyXXXI., 39-40. "In the Gallic provinces in Germany they pour salt water upon burning wood. The Spaniards in a certain place draw the brine from wells, which they callMuria. They indeed think that the wood turns to salt, and that the oak is the best, being the kind which is itself salty. Elsewhere the hazel is praised. Thus the charcoal even is turned into salt when it is steeped in brine. Whenever salt is made with wood it is black."
[Pg 558][5]PlinyXXXI., 39-40. "In the Gallic provinces in Germany they pour salt water upon burning wood. The Spaniards in a certain place draw the brine from wells, which they callMuria. They indeed think that the wood turns to salt, and that the oak is the best, being the kind which is itself salty. Elsewhere the hazel is praised. Thus the charcoal even is turned into salt when it is steeped in brine. Whenever salt is made with wood it is black."
[6]We have elsewhere in this book used the word "soda" for the Latin termnitrum, because we believe as used by Agricola it was always soda, and because some confusion of this term with its modern adaptation for saltpetre (nitre) might arise in the mind of the reader. Fortunately, Agricola usually carefully mentions other alkalis, such as the product from lixiviation of ashes, separately from hisnitrum. In these paragraphs, however, he has soda and potash hopelessly mixed, wherefore we have here introduced the Latin term. The actual difference between potash and soda—thenitrumof the Ancients, and thealkaliof Geber (and the glossary of Agricola), was not understood for two hundred years after Agricola, when Duhamel made his well-known determinations; and the isolation of sodium and potassium was, of course, still later by fifty years. If the reeds and rushes described in this paragraph grew near the sea, the salt from lixiviation would be soda, and likewise the Egyptian product was soda, but the lixiviation of wood-ash produces only potash; as seen above, all are termednitrumexcept the first.Historical Notes.—The wordnitrum,nitron,nitri,neter,nether, or similar forms, occurs in innumerable ancient writings. Among such references are Jeremiah (II., 22) Proverbs (XXV., 20), Herodotus (II., 86, 87), Aristotle (Prob.I., 39,De Mirab.54), Theophrastus (De Igne435 ed. Heinsii, Hist. PlantsIII., 9), Dioscorides (V., 89), Pliny (XIV., 26, andXXXI., 46). A review of disputations on what salts this term comprised among the Ancients would itself fill a volume, but from the properties named it was no doubt mostly soda, more rarely potash, and sometimes both mixed with common salt. There is every reason to believe from the properties and uses mentioned, that it did not generally comprise nitre (saltpetre)—into which superficial error the nomenclature has led many translators. The preparation by way of burning, and the use ofnitrumfor purposes for which we now use soap, for making glass, for medicines, cosmetics, salves, painting, in baking powder, for preserving food, embalming, etc., and the descriptions of its taste in "nitrous" waters,—all answer for soda and potash, but not for saltpetre. It is possible that the common occurrence of saltpetre as an efflorescence on walls might naturally lead to its use, but in any event its distinguishing characteristics are nowhere mentioned. As sal-ammoniac occurred[Pg 559]in the volcanoes in Italy, it also may have been included in thenitrummentioned.Nitrumwas in the main exported from Egypt, but Theophrastus mentions its production from wood-ash, and Pliny very rightly states that burned lees of wine (argol) had the nature ofnitrum. Many of the ancient writers understood that it was rendered more caustic by burning, and still more so by treatment with lime. According to Beckmann (Hist. of InventionsII., p. 488), the form of the wordnatronwas first introduced into Europe by two travellers in Egypt, Peter Ballon and Prosper Alpinus, about 1550. The word was introduced into mineralogy by Linnaeus in 1736. In the first instancenatronwas applied to[Pg 560]soda and potash in distinction tonitrefor saltpetre, and laternatronwas applied solely to soda.It is desirable to mention here two other forms of soda and potash which are frequently mentioned by Agricola. "Ashes which wool dyers use" (cineres quo infectores lanarum utuntur).—There is no indication in any of Agricola's works as to whether this was some special wood-ash or whether it was the calcined residues from wool washing. The "yolk" or "suint" of wool, originating from the perspiration of the animal, has long been a source of crude potash. The water, after washing the wool, is evaporated, and the residue calcined. It contains about 85% K2CO3, the remainder being sodium and potassium sulphates. Another reason for assuming that it was not a wood-ash product, is that these products are separately mentioned. In either event, whether obtained from wool residues or from lixiviation of wood-ash, it would be an impure potash. In some methods of wool dyeing, a wash of soda was first given, so that it is barely possible that this substance was sodium carbonate."Salt made from the ashes of musk ivy" (sal ex anthyllidis cinere factus,—Glossary,salalkali). This would be largely potash.
[6]We have elsewhere in this book used the word "soda" for the Latin termnitrum, because we believe as used by Agricola it was always soda, and because some confusion of this term with its modern adaptation for saltpetre (nitre) might arise in the mind of the reader. Fortunately, Agricola usually carefully mentions other alkalis, such as the product from lixiviation of ashes, separately from hisnitrum. In these paragraphs, however, he has soda and potash hopelessly mixed, wherefore we have here introduced the Latin term. The actual difference between potash and soda—thenitrumof the Ancients, and thealkaliof Geber (and the glossary of Agricola), was not understood for two hundred years after Agricola, when Duhamel made his well-known determinations; and the isolation of sodium and potassium was, of course, still later by fifty years. If the reeds and rushes described in this paragraph grew near the sea, the salt from lixiviation would be soda, and likewise the Egyptian product was soda, but the lixiviation of wood-ash produces only potash; as seen above, all are termednitrumexcept the first.
Historical Notes.—The wordnitrum,nitron,nitri,neter,nether, or similar forms, occurs in innumerable ancient writings. Among such references are Jeremiah (II., 22) Proverbs (XXV., 20), Herodotus (II., 86, 87), Aristotle (Prob.I., 39,De Mirab.54), Theophrastus (De Igne435 ed. Heinsii, Hist. PlantsIII., 9), Dioscorides (V., 89), Pliny (XIV., 26, andXXXI., 46). A review of disputations on what salts this term comprised among the Ancients would itself fill a volume, but from the properties named it was no doubt mostly soda, more rarely potash, and sometimes both mixed with common salt. There is every reason to believe from the properties and uses mentioned, that it did not generally comprise nitre (saltpetre)—into which superficial error the nomenclature has led many translators. The preparation by way of burning, and the use ofnitrumfor purposes for which we now use soap, for making glass, for medicines, cosmetics, salves, painting, in baking powder, for preserving food, embalming, etc., and the descriptions of its taste in "nitrous" waters,—all answer for soda and potash, but not for saltpetre. It is possible that the common occurrence of saltpetre as an efflorescence on walls might naturally lead to its use, but in any event its distinguishing characteristics are nowhere mentioned. As sal-ammoniac occurred[Pg 559]in the volcanoes in Italy, it also may have been included in thenitrummentioned.Nitrumwas in the main exported from Egypt, but Theophrastus mentions its production from wood-ash, and Pliny very rightly states that burned lees of wine (argol) had the nature ofnitrum. Many of the ancient writers understood that it was rendered more caustic by burning, and still more so by treatment with lime. According to Beckmann (Hist. of InventionsII., p. 488), the form of the wordnatronwas first introduced into Europe by two travellers in Egypt, Peter Ballon and Prosper Alpinus, about 1550. The word was introduced into mineralogy by Linnaeus in 1736. In the first instancenatronwas applied to[Pg 560]soda and potash in distinction tonitrefor saltpetre, and laternatronwas applied solely to soda.
It is desirable to mention here two other forms of soda and potash which are frequently mentioned by Agricola. "Ashes which wool dyers use" (cineres quo infectores lanarum utuntur).—There is no indication in any of Agricola's works as to whether this was some special wood-ash or whether it was the calcined residues from wool washing. The "yolk" or "suint" of wool, originating from the perspiration of the animal, has long been a source of crude potash. The water, after washing the wool, is evaporated, and the residue calcined. It contains about 85% K2CO3, the remainder being sodium and potassium sulphates. Another reason for assuming that it was not a wood-ash product, is that these products are separately mentioned. In either event, whether obtained from wool residues or from lixiviation of wood-ash, it would be an impure potash. In some methods of wool dyeing, a wash of soda was first given, so that it is barely possible that this substance was sodium carbonate.
"Salt made from the ashes of musk ivy" (sal ex anthyllidis cinere factus,—Glossary,salalkali). This would be largely potash.
[7]This wondrous illustration of soda-making from Nile water is no doubt founded upon Pliny (XXXI., 46). "It is made in almost the same manner as salt, except that sea-water is put into salt pans, whereas in the nitrous pans it is water of the Nile; these, with the subsidence of the Nile during the forty days, are impregnated withnitrum."
[7]This wondrous illustration of soda-making from Nile water is no doubt founded upon Pliny (XXXI., 46). "It is made in almost the same manner as salt, except that sea-water is put into salt pans, whereas in the nitrous pans it is water of the Nile; these, with the subsidence of the Nile during the forty days, are impregnated withnitrum."
[8]This paragraph displays hopeless ignorance. Borax was known to Agricola and greatly used in his time; it certainly was not made from these compounds, but was imported from Central Asia. Sal-ammoniac was also known in his time, and was used like borax as a soldering agent. The reaction given by Agricola would yield free ammonia. The following historical notes on borax and sal-ammoniac may be of service.Borax.—The uncertainties of the ancient distinctions in salts involve borax deeply. The wordBaurachoccurs in Geber and the other early Alchemistic writings, but there is nothing to prove that it was modern borax. There cannot be the slightest doubt, however, that the material referred to by Agricola asboraxwas our borax, because of the characteristic qualities incidentally mentioned inBook VII. That he believed it was an artificial product fromnitrumis evident enough from his usual expression "chrysocollamade fromnitrum, which the Moors callborax." Agricola, inDe Natura Fossilium(p. 206-7), makes the following statements, which could leave no doubt on the subject:—"Nativenitrumis found in the earth or on the surface.... It is from this variety that the Venetians makechrysocolla, which I callborax.... The second variety of artificialnitrumis made at the present day from the nativenitrum, called by the Arabstincar, but I call it usually by the Greek namechrysocolla; it is really the Arabicborax.... Thisnitrumdoes not decrepitate nor fly out of the fire; however, the native variety swells up from within." The application of the wordchrysocolla(chrysos, gold;colla, solder) to soldering materials, and at the same time to the copper mineral, is of Greek origin. If any further proof were needed as to the substance meant by Agricola, it lies in the wordtincar. For a long time the borax of Europe was imported from Central Asia, through Constantinople and Venice, under the name oftincalortincar. When this trade began, we do not know; evidently before Agricola's time. The statement here of making borax from alum and sal-ammoniac is identical with the assertion of Biringuccio (II., 9).Sal-ammoniac.—The early history of this—ammonium chloride—is also under a cloud. Pliny (XXXI., 39) speaks of asal-hammoniacum, and Dioscorides (V., 85) uses much the same word. Pliny describes it as from near the temple of Ammon in Egypt. None of the distinctive characteristics of sal-ammoniac are mentioned, and there is every reason to believe it was either common salt or soda. Herodotus, Strabo, and others mention common salt sent from about the same locality. The first authentic mention is in Geber, who calls itsal-ammoniacum, and describes a method of making, and several characteristic reactions. It was known in the Middle Ages under various names, among themsal-aremonicum. Agricola (De Nat. Fos.,III., p. 206) notes its characteristic quality of volatilization. "Sal-ammoniac ... in the fire neither crackles nor flies out, but is totally consumed." He also says (p. 208): "Borax is used by goldsmiths to solder gold, likewise silver. The artificers who make iron needles (tacks?) similarly use sal-ammoniac when they cover the heads with tin." The statement from Pliny mentioned in this paragraph is fromXXXIII., 29, where he describes thechrysocollaused as gold solder as made from verdigris,nitrum, and urine in the way quoted. It is quite possible that this solder was sal-ammoniac, though not made in quite this manner. Pliny refers in several places (XXXIII., 26, 27, 28, and 29,XXXV., 28, etc.) tochrysocolla, about which he is greatly confused as between gold-solder, the copper mineral, and a green pigment, the latter being of either mineral origin.
[8]This paragraph displays hopeless ignorance. Borax was known to Agricola and greatly used in his time; it certainly was not made from these compounds, but was imported from Central Asia. Sal-ammoniac was also known in his time, and was used like borax as a soldering agent. The reaction given by Agricola would yield free ammonia. The following historical notes on borax and sal-ammoniac may be of service.
Borax.—The uncertainties of the ancient distinctions in salts involve borax deeply. The wordBaurachoccurs in Geber and the other early Alchemistic writings, but there is nothing to prove that it was modern borax. There cannot be the slightest doubt, however, that the material referred to by Agricola asboraxwas our borax, because of the characteristic qualities incidentally mentioned inBook VII. That he believed it was an artificial product fromnitrumis evident enough from his usual expression "chrysocollamade fromnitrum, which the Moors callborax." Agricola, inDe Natura Fossilium(p. 206-7), makes the following statements, which could leave no doubt on the subject:—"Nativenitrumis found in the earth or on the surface.... It is from this variety that the Venetians makechrysocolla, which I callborax.... The second variety of artificialnitrumis made at the present day from the nativenitrum, called by the Arabstincar, but I call it usually by the Greek namechrysocolla; it is really the Arabicborax.... Thisnitrumdoes not decrepitate nor fly out of the fire; however, the native variety swells up from within." The application of the wordchrysocolla(chrysos, gold;colla, solder) to soldering materials, and at the same time to the copper mineral, is of Greek origin. If any further proof were needed as to the substance meant by Agricola, it lies in the wordtincar. For a long time the borax of Europe was imported from Central Asia, through Constantinople and Venice, under the name oftincalortincar. When this trade began, we do not know; evidently before Agricola's time. The statement here of making borax from alum and sal-ammoniac is identical with the assertion of Biringuccio (II., 9).
Sal-ammoniac.—The early history of this—ammonium chloride—is also under a cloud. Pliny (XXXI., 39) speaks of asal-hammoniacum, and Dioscorides (V., 85) uses much the same word. Pliny describes it as from near the temple of Ammon in Egypt. None of the distinctive characteristics of sal-ammoniac are mentioned, and there is every reason to believe it was either common salt or soda. Herodotus, Strabo, and others mention common salt sent from about the same locality. The first authentic mention is in Geber, who calls itsal-ammoniacum, and describes a method of making, and several characteristic reactions. It was known in the Middle Ages under various names, among themsal-aremonicum. Agricola (De Nat. Fos.,III., p. 206) notes its characteristic quality of volatilization. "Sal-ammoniac ... in the fire neither crackles nor flies out, but is totally consumed." He also says (p. 208): "Borax is used by goldsmiths to solder gold, likewise silver. The artificers who make iron needles (tacks?) similarly use sal-ammoniac when they cover the heads with tin." The statement from Pliny mentioned in this paragraph is fromXXXIII., 29, where he describes thechrysocollaused as gold solder as made from verdigris,nitrum, and urine in the way quoted. It is quite possible that this solder was sal-ammoniac, though not made in quite this manner. Pliny refers in several places (XXXIII., 26, 27, 28, and 29,XXXV., 28, etc.) tochrysocolla, about which he is greatly confused as between gold-solder, the copper mineral, and a green pigment, the latter being of either mineral origin.
[Pg 561][9]Saltpetre was secured in the Middle Ages in two ways, but mostly from the treatment of calcium nitrate efflorescence on cellar and similar walls, and from so-called saltpetre plantations. In this description of the latter, one of the most essential factors is omitted until the last sentence,i.e., that the nitrous earth was the result of the decay of organic or animal matter over a long period. Such decomposition, in the presence of potassium and calcium carbonates—the lye and lime—form potassium and calcium nitrates, together with some magnesium and sodium nitrates. After lixiviation, the addition of lye converts the calcium and magnesium nitrates into saltpetre,i.e., Ca(NO3)2+ K2CO3= CaCO3+ 2KNO3. The carbonates precipitate out, leaving the saltpetre in solution, from which it was evaporated and crystallized out. The addition of alum as mentioned would scarcely improve the situation.The purification by repeated re-solution and addition of lye, and filtration, would eliminate the remaining other salts. The purification with sulphur, however, is more difficult[Pg 562]to understand. In this case the saltpetre is melted and the sulphur added and set alight. Such an addition to saltpetre would no doubt burn brilliantly. The potassium sulphate formed would possibly settle to the bottom, and if the "greasy matter" were simply organic impurities, they might be burned off. This method of refining appears to have been copied from Biringuccio (X., 1), who states it in almost identical terms.Historical Note.—As mentioned inNote 6 above, it is quite possible that the Ancients did include efflorescence of walls undernitrum; but, so far as we are aware, no specific mention of such an occurrence ofnitrumis given, and, as stated before, there is every reason to believe that all the substances under that term were soda and potash. Especially the frequent mention of the preparation ofnitrumby way of burning, argues strongly against saltpetre being included, as they would hardly have failed to notice the decrepitation. Argument has been put forward that Greek fire contained saltpetre, but it amounts to nothing more than argument, for in those receipts preserved, no salt of any kind is mentioned. It is most likely that the leprosy of house-walls of the Mosaic code (LeviticusXIV., 34 to 53) was saltpetre efflorescence. The drastic treatment by way of destruction of such "unclean" walls and houses, however, is sufficient evidence that this salt was not used. The first certain mention of saltpetre (sal petrae) is in Geber. As stated before, the date of this work is uncertain; in any event it was probably as early as the 13th Century. He describes the making of "solvative water" with alum and saltpetre, so there can be no doubt as to the substance (see Note on p.460, on nitric acid). There is also a work by a nebulous Marcus Graecus, where the wordsal petrosumis used. And it appears that Roger Bacon (died 1294) and Albertus Magnus (died 1280) both had access to that work. Bacon uses the termsal petraefrequently enough, and was the first to describe gunpowder (De Mirabili Potestate Artis et Naturae1242). He gives no mention of the method of making hissal petrae. Agricola uses throughout the Latin text the termhalinitrum, a word he appears to have coined himself. However, he gives its German equivalent in theInterpretatioassalpeter. The only previous description of the method of making saltpetre, of which we are aware, is that of Biringuccio (1540), who mentions the boiling of the excrescences from walls, and also says a good deal about boiling solutions from "nitrous" earth, which may or may not be of "plantation" origin. He also gives this same method of refining with sulphur. In any event, this statement by Agricola is the first clear and complete description of the saltpetre "plantations." Saltpetre was in great demand in the Middle Ages for the manufacture of gunpowder, and the first record of that substance and of explosive weapons necessarily involves the knowledge of saltpetre. However, authentic mention of such weapons only begins early in the 14th Century. Among the earliest is an authority to the Council of Twelve at Florence to appoint persons to make cannon, etc., (1326), references to cannon in the stores of the Tower of London, 1388, &c.
[Pg 561][9]Saltpetre was secured in the Middle Ages in two ways, but mostly from the treatment of calcium nitrate efflorescence on cellar and similar walls, and from so-called saltpetre plantations. In this description of the latter, one of the most essential factors is omitted until the last sentence,i.e., that the nitrous earth was the result of the decay of organic or animal matter over a long period. Such decomposition, in the presence of potassium and calcium carbonates—the lye and lime—form potassium and calcium nitrates, together with some magnesium and sodium nitrates. After lixiviation, the addition of lye converts the calcium and magnesium nitrates into saltpetre,i.e., Ca(NO3)2+ K2CO3= CaCO3+ 2KNO3. The carbonates precipitate out, leaving the saltpetre in solution, from which it was evaporated and crystallized out. The addition of alum as mentioned would scarcely improve the situation.
The purification by repeated re-solution and addition of lye, and filtration, would eliminate the remaining other salts. The purification with sulphur, however, is more difficult[Pg 562]to understand. In this case the saltpetre is melted and the sulphur added and set alight. Such an addition to saltpetre would no doubt burn brilliantly. The potassium sulphate formed would possibly settle to the bottom, and if the "greasy matter" were simply organic impurities, they might be burned off. This method of refining appears to have been copied from Biringuccio (X., 1), who states it in almost identical terms.
Historical Note.—As mentioned inNote 6 above, it is quite possible that the Ancients did include efflorescence of walls undernitrum; but, so far as we are aware, no specific mention of such an occurrence ofnitrumis given, and, as stated before, there is every reason to believe that all the substances under that term were soda and potash. Especially the frequent mention of the preparation ofnitrumby way of burning, argues strongly against saltpetre being included, as they would hardly have failed to notice the decrepitation. Argument has been put forward that Greek fire contained saltpetre, but it amounts to nothing more than argument, for in those receipts preserved, no salt of any kind is mentioned. It is most likely that the leprosy of house-walls of the Mosaic code (LeviticusXIV., 34 to 53) was saltpetre efflorescence. The drastic treatment by way of destruction of such "unclean" walls and houses, however, is sufficient evidence that this salt was not used. The first certain mention of saltpetre (sal petrae) is in Geber. As stated before, the date of this work is uncertain; in any event it was probably as early as the 13th Century. He describes the making of "solvative water" with alum and saltpetre, so there can be no doubt as to the substance (see Note on p.460, on nitric acid). There is also a work by a nebulous Marcus Graecus, where the wordsal petrosumis used. And it appears that Roger Bacon (died 1294) and Albertus Magnus (died 1280) both had access to that work. Bacon uses the termsal petraefrequently enough, and was the first to describe gunpowder (De Mirabili Potestate Artis et Naturae1242). He gives no mention of the method of making hissal petrae. Agricola uses throughout the Latin text the termhalinitrum, a word he appears to have coined himself. However, he gives its German equivalent in theInterpretatioassalpeter. The only previous description of the method of making saltpetre, of which we are aware, is that of Biringuccio (1540), who mentions the boiling of the excrescences from walls, and also says a good deal about boiling solutions from "nitrous" earth, which may or may not be of "plantation" origin. He also gives this same method of refining with sulphur. In any event, this statement by Agricola is the first clear and complete description of the saltpetre "plantations." Saltpetre was in great demand in the Middle Ages for the manufacture of gunpowder, and the first record of that substance and of explosive weapons necessarily involves the knowledge of saltpetre. However, authentic mention of such weapons only begins early in the 14th Century. Among the earliest is an authority to the Council of Twelve at Florence to appoint persons to make cannon, etc., (1326), references to cannon in the stores of the Tower of London, 1388, &c.
[Pg 564][10]There are three methods of manufacturing alum described by Agricola, the first and third apparently from shales, and the second from alum rock or "alunite." The reasons for assuming that the first process was from shales, are the reference to the "aluminous earth" as ore (venae) coming from "veins," and also the mixture of vitriol. In this process the free sulphuric acid formed by the oxidation of pyrites reacts upon the argillaceous material to form aluminium sulphate. The decomposed ore is then placed in tanks and lixiviated. The solution would contain aluminium sulphate, vitriol, and other impurities. By the addition of urine, the aluminium sulphate would be converted into ammonia alum. Agricola is, of course, mistaken as to the effect of the addition, being under the belief that it separated the vitriol from the alum; in fact, this belief was general until the latter part of the 18th Century, when Lavoisier determined that alum must have an alkali base. Nor is it clear[Pg 565]from this description exactly how they were separated. In a condensed solution allowed to cool, the alum would precipitate out as "alum meal," and the vitriol would "float on top"—in solution. The reference to "meal" may represent this phenomenon, and the re-boiling referred to would be the normal method of purification by crystallization. The "asbestos" and gypsum deposited in the caldrons were no doubt feathery and mealy calcium sulphate. The alum produced would, in any event, be mostly ammonia alum.The second process is certainly the manufacture from "alum rock" or "alunite" (the hydrous sulphate of aluminium and potassium), such as that mined at La Tolfa in the Papal States, where the process has been for centuries identical with that here described. The alum there produced is the double basic potassium alum, and crystallizes into cubes instead of octahedra,i.e., the Roman alum of commerce. The presence of much ferric oxide gives the rose colour referred to by Agricola. This account is almost identical with that of Biringuccio (II., 4), and it appears from similarity of details that Agricola, as stated in hispreface, must have "refreshed his mind" from this description; it would also appear from theprefacethat he had himself visited the locality.The third process is essentially the same as the first, except that the decomposition of the pyrites was hastened by roasting. The following obscure statement of some interest occurs in Agricola'sDe Natura Fossilium, p. 209:—"... alum is made from vitriol, for when oil is made from the latter, alum is distilled out (expirat). This absorbs the clay which is used in cementing glass, and when the operation is complete the clay is macerated with pure water, and the alum is soon afterward deposited in the shape of small cubes." Assuming the oil of vitriol to be sulphuric acid and the clay "used in cementing glass" to be kaolin, we have here the first suggestion of a method for producing alum which came into use long after."Burnt alum" (alumen coctum).—Agricola frequently uses this expression, and on p.568, describes the operation, and the substance is apparently the same as modern dehydrated alum, often referred to as "burnt alum."Historical Notes.—Whether the Ancients knew of alum in the modern sense is a most vexed question. The Greeks refer to a certain substance asstypteria, and the Romans refer to this same substance asalumen. There can be no question as to their knowledge and common use of vitriol, nor that substances which they believed were entirely different from vitriol were comprised under the above names. Beckmann (Hist. of Inventions, Vol.I., p. 181) seems to have been the founder of the doctrine that the ancientalumenwas vitriol, and scores of authorities seem to have adopted his arguments without inquiry, until that belief[Pg 566]is now general. One of the strongest reasons put forward was that alum does not occur native in appreciable quantities. Apart from the fact that the weight of this argument has been lost by the discovery that alum does occur in nature to some extent as an aftermath of volcanic action, and as an efflorescence from argillaceous rocks, we see no reason why the Ancients may not have prepared it artificially. One of the earliest mentions of such a substance is by Herodotus (II., 180) of a thousand talents ofstypteria, sent by Amasis from Egypt as a contribution to the rebuilding of the temple of Delphi. Diodorus (V., 1) mentions the abundance which was secured from the Lipari Islands (Stromboli, etc.), and a small quantity from the Isle of Melos. Dioscorides (V., 82) mentions Egypt, Lipari Islands, Melos, Sardinia, Armenia, etc., "and generally in any other places where one finds red ochre (rubrica)." Pliny (XXXV., 52) gives these same localities, and is more explicit as to how it originates—"from an earthy water which exudes from the earth." Of these localities, the Lipari Islands (Stromboli, etc.), and Melos are volcanic enough, and both Lipari and Melos are now known to produce natural alum (Dana. Syst. Min., p. 95; and Tournefort, "Relation d'un voyage du Levant." London, 1717,LettreIV., Vol. 1.). Further, the hair-like alum of Dioscorides, repeated by Pliny below, was quite conceivably fibrouskalinite, native potash alum, which occurs commonly as an efflorescence. Be the question of native alum as it may—and vitriol is not much more common—our own view that the ancientalumenwas alum, is equally based upon the artificial product. Before entering upon the subject, we consider it desirable to set out the properties of the ancient substance, a complete review of which is given by Pliny (XXXV., 52), he obviously quoting also from Dioscorides, which, therefore, we do not need to reproduce. Pliny says:—"Not less important, or indeed dissimilar, are the uses made ofalumen; by which name is understood a sort of salty earth. Of this, there are several kinds. In Cyprus there is a whitealumen, and a darker kind. There is not a great difference in their colour, though the uses made of them are very dissimilar,—the whitealumenbeing employed in a liquid state for dyeing wool bright colours, and the dark-colouredalumen, on the other hand, for giving wool a sombre tint. Gold is purified with blackalumen. Every kind ofalumenis from alimuswater which exudes from the earth. The collection of it commences in winter, and it is dried by the summer sun. That portion of it which first matures is the whitest. It is obtained in Spain, Egypt, Armenia, Macedonia, Pontus, Africa, and the islands of Sardinia, Melos, Lipari, and Strongyle; the most esteemed, however, is that of Egypt, the next best from Melos. Of this last there are two kinds, the liquidalumen, and the solid. Liquidalumen, to be good, should be of a limpid and milky appearance; when[Pg 568]rubbed, it should be without roughness, and should give a little heat. This is calledphorimon. The mode of detecting whether it has been adulterated is by pomegranate juice, for, if genuine, the mixture turns black. The other, or solid, is pale and rough and turns dark with nut-galls; for which reason it is calledparaphoron. Liquidalumenis naturally astringent, indurative, and corrosive; used in combination with honey, it heals ulcerations.... There is one kind of solidalumen, called by the Greeksschistos, which splits into filaments of a whitish colour; for which reason some prefer calling ittrichitis(hair like).Alumenis produced from the stonechalcitis, from which copper is also made, being a sort of coagulated scum from that stone. This kind ofalumenis less astringent than the others, and is less useful as a check upon bad humours of the body.... The mode of preparing it is to cook it in a pan until it has ceased being a liquid. There is another variety ofalumenalso, of a less active nature, calledstrongyle. It is of two kinds. The fungous, which easily dissolves, is utterly condemned. The better kind is the pumice-like kind, full of small holes like a sponge, and is in round pieces, more nearly white in colour, somewhat greasy, free from grit, friable, and does not stain black. This last kind is cooked by itself upon charcoal until it is reduced to pure ashes. The best kind of all is that calledmelinum, from the Isle of Melos, as I have said, none being more effectual as an astringent, for staining black, and for indurating, and none becomes more dry.... Above all other properties ofalumenis its remarkable astringency, whence its Greek name.... It is injected for dysentry and employed as a gargle." The lines omitted refer entirely to medical matters which have no bearing here. The following paragraph (often overlooked) from Pliny (XXXV., 42) also has an important bearing upon the subject:—"In Egypt they employ a wonderful method of dyeing. The white cloth, after it is pressed, is stained in various places, not with dye stuffs, but with substances which absorb colours. These applications are not apparent on the cloth, but when it is immersed in a caldron of hot dye it is removed the next moment brightly coloured. The remarkable circumstance is that although there be only one dye in the caldron yet different colours appear in the cloth."It is obvious from Pliny's description above, and also from the making of vitriol (seeNote 11, p. 572), that this substance was obtained from liquor resulting from natural or artificial lixiviation of rocks—in the case of vitriols undoubtedly the result of decomposition of pyritiferous rocks (such aschalcitis). Such liquors are bound to contain aluminum sulphate if there is any earth or clay about, and whether they contained alum would be a question of an alkali being present. If no alkali were present in this liquor, vitriol would[Pg 569]crystallize out first, and subsequent condensation would yield aluminum sulphate. If alkali were present, the alum would crystallize out either before or with the vitriol. Pliny's remark, "that portion of it which first matures is whitest", agrees well enough with this hypothesis. No one will doubt that some of the properties mentioned above belong peculiarly to vitriol, but equally convincing are properties and uses that belong to alum alone. The strongly astringent taste, white colour, and injection for dysentry, are more peculiar to alum than to vitriol. But above all other properties is that displayed in dyeing, for certainly if we read this last quotation from Pliny in conjunction with the statement that whitealumenproduces bright colours and the dark kind, sombre colours, we have the exact reactions of alum and vitriol when used as mordants. Therefore, our view is that the ancient salt of this character was a more or less impure mixture ranging from alum to vitriol—"the whiter the better." Further, considering the ancient knowledge of soda (nitrum), and the habit of mixing it into almost everything, it does not require much flight of imagination to conceive its admixture to the "water," and the absolute production of alum.Whatever may have been the confusion between alum and vitriol among the Ancients, it appears that by the time of the works attributed to Geber (12th or 13th Century), the difference was well known. His work (Investigationes perfectiones,IV.) refers toalumen glacialeandalumen jamenias distinguished from vitriol, and gives characteristic reactions which can leave no doubt as to the distinction. We may remark here that the repeated statement apparently arising from Meyer (History of Chemistry, p. 51) that Geber used the termalum de roccais untrue, this term not appearing in the early Latin translations. During the 15th Century alum did come to be known in Europe asalum de rocca. Various attempts have been made to explain the origin of this term, ranging from the Italian root, a "rock," to the town of Rocca in Syria, where alum was supposed to have been produced. In any event, the supply for a long period prior to the middle of the 15th Century came from Turkey, and the origin of the methods of manufacture described by Agricola, and used down to the present day, must have come from the Orient.In the early part of the 15th Century, a large trade in alum was done between Italy and Asia Minor, and eventually various Italians established themselves near Constantinople and Smyrna for its manufacture (Dudae,Historia Byzantina Venetia, 1729, p. 71). The alum was secured by burning the rock, and lixiviation. With the capture of Constantinople by the Turks (1453), great feeling grew up in Italy over the necessity of buying this requisite for their dyeing establishments from the infidel, and considerable exertion was made to find other sources of supply. Some minor works were attempted, but nothing much[Pg 570]eventuated until the appearance of one John de Castro. From the Commentaries of Pope PiusII.(1614, p. 185), it appears that this Italian had been engaged in dyeing cloth in Constantinople, and thus became aware of the methods of making alum. Driven out of that city through its capture by the Turks, he returned to Italy and obtained an office under the Apostolic Chamber. While in this occupation he discovered a rock at Tolfa which appeared to him identical with that used at Constantinople in alum manufacture. After experimental work, he sought the aid of the Pope, which he obtained after much vicissitude. Experts were sent, who after examination "shed tears of joy, they kneeling down three times, worshipped God and praised His kindness in conferring such a gift on their age." Castro was rewarded, and the great papal monopoly was gradually built upon this discovery. The industry firmly established at Tolfa exists to the present day, and is the source of the Roman alum of commerce. The Pope maintained this monopoly strenuously, by fair means and by excommunication, gradually advancing the price until the consumers had greater complaint than against the Turks. The history of the disputes arising over the papal alum monopoly would alone fill a volume.By the middle of the 15th Century alum was being made in Spain, Holland, and Germany, and later in England. In her efforts to encourage home industries and escape the tribute to the Pope, Elizabeth (see Note on p.283) invited over "certain foreign chymistes and mineral masters" and gave them special grants to induce them to "settle in these realmes." Among them was Cornelius Devoz, to whom was granted the privilege of "mining and digging in our Realm of England for allom and copperas." What Devoz accomplished is not recorded, but the first alum manufacture on a considerable scale seems to have been in Yorkshire, by one Thomas Chaloner (about 1608), who was supposed to have seduced workmen from the Pope's alum works at Tolfa, for which he was duly cursed with all the weight of the Pope and Church. (Pennant, Tour of Scotland, 1786).
[Pg 564][10]There are three methods of manufacturing alum described by Agricola, the first and third apparently from shales, and the second from alum rock or "alunite." The reasons for assuming that the first process was from shales, are the reference to the "aluminous earth" as ore (venae) coming from "veins," and also the mixture of vitriol. In this process the free sulphuric acid formed by the oxidation of pyrites reacts upon the argillaceous material to form aluminium sulphate. The decomposed ore is then placed in tanks and lixiviated. The solution would contain aluminium sulphate, vitriol, and other impurities. By the addition of urine, the aluminium sulphate would be converted into ammonia alum. Agricola is, of course, mistaken as to the effect of the addition, being under the belief that it separated the vitriol from the alum; in fact, this belief was general until the latter part of the 18th Century, when Lavoisier determined that alum must have an alkali base. Nor is it clear[Pg 565]from this description exactly how they were separated. In a condensed solution allowed to cool, the alum would precipitate out as "alum meal," and the vitriol would "float on top"—in solution. The reference to "meal" may represent this phenomenon, and the re-boiling referred to would be the normal method of purification by crystallization. The "asbestos" and gypsum deposited in the caldrons were no doubt feathery and mealy calcium sulphate. The alum produced would, in any event, be mostly ammonia alum.
The second process is certainly the manufacture from "alum rock" or "alunite" (the hydrous sulphate of aluminium and potassium), such as that mined at La Tolfa in the Papal States, where the process has been for centuries identical with that here described. The alum there produced is the double basic potassium alum, and crystallizes into cubes instead of octahedra,i.e., the Roman alum of commerce. The presence of much ferric oxide gives the rose colour referred to by Agricola. This account is almost identical with that of Biringuccio (II., 4), and it appears from similarity of details that Agricola, as stated in hispreface, must have "refreshed his mind" from this description; it would also appear from theprefacethat he had himself visited the locality.
The third process is essentially the same as the first, except that the decomposition of the pyrites was hastened by roasting. The following obscure statement of some interest occurs in Agricola'sDe Natura Fossilium, p. 209:—"... alum is made from vitriol, for when oil is made from the latter, alum is distilled out (expirat). This absorbs the clay which is used in cementing glass, and when the operation is complete the clay is macerated with pure water, and the alum is soon afterward deposited in the shape of small cubes." Assuming the oil of vitriol to be sulphuric acid and the clay "used in cementing glass" to be kaolin, we have here the first suggestion of a method for producing alum which came into use long after.
"Burnt alum" (alumen coctum).—Agricola frequently uses this expression, and on p.568, describes the operation, and the substance is apparently the same as modern dehydrated alum, often referred to as "burnt alum."
Historical Notes.—Whether the Ancients knew of alum in the modern sense is a most vexed question. The Greeks refer to a certain substance asstypteria, and the Romans refer to this same substance asalumen. There can be no question as to their knowledge and common use of vitriol, nor that substances which they believed were entirely different from vitriol were comprised under the above names. Beckmann (Hist. of Inventions, Vol.I., p. 181) seems to have been the founder of the doctrine that the ancientalumenwas vitriol, and scores of authorities seem to have adopted his arguments without inquiry, until that belief[Pg 566]is now general. One of the strongest reasons put forward was that alum does not occur native in appreciable quantities. Apart from the fact that the weight of this argument has been lost by the discovery that alum does occur in nature to some extent as an aftermath of volcanic action, and as an efflorescence from argillaceous rocks, we see no reason why the Ancients may not have prepared it artificially. One of the earliest mentions of such a substance is by Herodotus (II., 180) of a thousand talents ofstypteria, sent by Amasis from Egypt as a contribution to the rebuilding of the temple of Delphi. Diodorus (V., 1) mentions the abundance which was secured from the Lipari Islands (Stromboli, etc.), and a small quantity from the Isle of Melos. Dioscorides (V., 82) mentions Egypt, Lipari Islands, Melos, Sardinia, Armenia, etc., "and generally in any other places where one finds red ochre (rubrica)." Pliny (XXXV., 52) gives these same localities, and is more explicit as to how it originates—"from an earthy water which exudes from the earth." Of these localities, the Lipari Islands (Stromboli, etc.), and Melos are volcanic enough, and both Lipari and Melos are now known to produce natural alum (Dana. Syst. Min., p. 95; and Tournefort, "Relation d'un voyage du Levant." London, 1717,LettreIV., Vol. 1.). Further, the hair-like alum of Dioscorides, repeated by Pliny below, was quite conceivably fibrouskalinite, native potash alum, which occurs commonly as an efflorescence. Be the question of native alum as it may—and vitriol is not much more common—our own view that the ancientalumenwas alum, is equally based upon the artificial product. Before entering upon the subject, we consider it desirable to set out the properties of the ancient substance, a complete review of which is given by Pliny (XXXV., 52), he obviously quoting also from Dioscorides, which, therefore, we do not need to reproduce. Pliny says:—
"Not less important, or indeed dissimilar, are the uses made ofalumen; by which name is understood a sort of salty earth. Of this, there are several kinds. In Cyprus there is a whitealumen, and a darker kind. There is not a great difference in their colour, though the uses made of them are very dissimilar,—the whitealumenbeing employed in a liquid state for dyeing wool bright colours, and the dark-colouredalumen, on the other hand, for giving wool a sombre tint. Gold is purified with blackalumen. Every kind ofalumenis from alimuswater which exudes from the earth. The collection of it commences in winter, and it is dried by the summer sun. That portion of it which first matures is the whitest. It is obtained in Spain, Egypt, Armenia, Macedonia, Pontus, Africa, and the islands of Sardinia, Melos, Lipari, and Strongyle; the most esteemed, however, is that of Egypt, the next best from Melos. Of this last there are two kinds, the liquidalumen, and the solid. Liquidalumen, to be good, should be of a limpid and milky appearance; when[Pg 568]rubbed, it should be without roughness, and should give a little heat. This is calledphorimon. The mode of detecting whether it has been adulterated is by pomegranate juice, for, if genuine, the mixture turns black. The other, or solid, is pale and rough and turns dark with nut-galls; for which reason it is calledparaphoron. Liquidalumenis naturally astringent, indurative, and corrosive; used in combination with honey, it heals ulcerations.... There is one kind of solidalumen, called by the Greeksschistos, which splits into filaments of a whitish colour; for which reason some prefer calling ittrichitis(hair like).Alumenis produced from the stonechalcitis, from which copper is also made, being a sort of coagulated scum from that stone. This kind ofalumenis less astringent than the others, and is less useful as a check upon bad humours of the body.... The mode of preparing it is to cook it in a pan until it has ceased being a liquid. There is another variety ofalumenalso, of a less active nature, calledstrongyle. It is of two kinds. The fungous, which easily dissolves, is utterly condemned. The better kind is the pumice-like kind, full of small holes like a sponge, and is in round pieces, more nearly white in colour, somewhat greasy, free from grit, friable, and does not stain black. This last kind is cooked by itself upon charcoal until it is reduced to pure ashes. The best kind of all is that calledmelinum, from the Isle of Melos, as I have said, none being more effectual as an astringent, for staining black, and for indurating, and none becomes more dry.... Above all other properties ofalumenis its remarkable astringency, whence its Greek name.... It is injected for dysentry and employed as a gargle." The lines omitted refer entirely to medical matters which have no bearing here. The following paragraph (often overlooked) from Pliny (XXXV., 42) also has an important bearing upon the subject:—"In Egypt they employ a wonderful method of dyeing. The white cloth, after it is pressed, is stained in various places, not with dye stuffs, but with substances which absorb colours. These applications are not apparent on the cloth, but when it is immersed in a caldron of hot dye it is removed the next moment brightly coloured. The remarkable circumstance is that although there be only one dye in the caldron yet different colours appear in the cloth."
It is obvious from Pliny's description above, and also from the making of vitriol (seeNote 11, p. 572), that this substance was obtained from liquor resulting from natural or artificial lixiviation of rocks—in the case of vitriols undoubtedly the result of decomposition of pyritiferous rocks (such aschalcitis). Such liquors are bound to contain aluminum sulphate if there is any earth or clay about, and whether they contained alum would be a question of an alkali being present. If no alkali were present in this liquor, vitriol would[Pg 569]crystallize out first, and subsequent condensation would yield aluminum sulphate. If alkali were present, the alum would crystallize out either before or with the vitriol. Pliny's remark, "that portion of it which first matures is whitest", agrees well enough with this hypothesis. No one will doubt that some of the properties mentioned above belong peculiarly to vitriol, but equally convincing are properties and uses that belong to alum alone. The strongly astringent taste, white colour, and injection for dysentry, are more peculiar to alum than to vitriol. But above all other properties is that displayed in dyeing, for certainly if we read this last quotation from Pliny in conjunction with the statement that whitealumenproduces bright colours and the dark kind, sombre colours, we have the exact reactions of alum and vitriol when used as mordants. Therefore, our view is that the ancient salt of this character was a more or less impure mixture ranging from alum to vitriol—"the whiter the better." Further, considering the ancient knowledge of soda (nitrum), and the habit of mixing it into almost everything, it does not require much flight of imagination to conceive its admixture to the "water," and the absolute production of alum.
Whatever may have been the confusion between alum and vitriol among the Ancients, it appears that by the time of the works attributed to Geber (12th or 13th Century), the difference was well known. His work (Investigationes perfectiones,IV.) refers toalumen glacialeandalumen jamenias distinguished from vitriol, and gives characteristic reactions which can leave no doubt as to the distinction. We may remark here that the repeated statement apparently arising from Meyer (History of Chemistry, p. 51) that Geber used the termalum de roccais untrue, this term not appearing in the early Latin translations. During the 15th Century alum did come to be known in Europe asalum de rocca. Various attempts have been made to explain the origin of this term, ranging from the Italian root, a "rock," to the town of Rocca in Syria, where alum was supposed to have been produced. In any event, the supply for a long period prior to the middle of the 15th Century came from Turkey, and the origin of the methods of manufacture described by Agricola, and used down to the present day, must have come from the Orient.
In the early part of the 15th Century, a large trade in alum was done between Italy and Asia Minor, and eventually various Italians established themselves near Constantinople and Smyrna for its manufacture (Dudae,Historia Byzantina Venetia, 1729, p. 71). The alum was secured by burning the rock, and lixiviation. With the capture of Constantinople by the Turks (1453), great feeling grew up in Italy over the necessity of buying this requisite for their dyeing establishments from the infidel, and considerable exertion was made to find other sources of supply. Some minor works were attempted, but nothing much[Pg 570]eventuated until the appearance of one John de Castro. From the Commentaries of Pope PiusII.(1614, p. 185), it appears that this Italian had been engaged in dyeing cloth in Constantinople, and thus became aware of the methods of making alum. Driven out of that city through its capture by the Turks, he returned to Italy and obtained an office under the Apostolic Chamber. While in this occupation he discovered a rock at Tolfa which appeared to him identical with that used at Constantinople in alum manufacture. After experimental work, he sought the aid of the Pope, which he obtained after much vicissitude. Experts were sent, who after examination "shed tears of joy, they kneeling down three times, worshipped God and praised His kindness in conferring such a gift on their age." Castro was rewarded, and the great papal monopoly was gradually built upon this discovery. The industry firmly established at Tolfa exists to the present day, and is the source of the Roman alum of commerce. The Pope maintained this monopoly strenuously, by fair means and by excommunication, gradually advancing the price until the consumers had greater complaint than against the Turks. The history of the disputes arising over the papal alum monopoly would alone fill a volume.
By the middle of the 15th Century alum was being made in Spain, Holland, and Germany, and later in England. In her efforts to encourage home industries and escape the tribute to the Pope, Elizabeth (see Note on p.283) invited over "certain foreign chymistes and mineral masters" and gave them special grants to induce them to "settle in these realmes." Among them was Cornelius Devoz, to whom was granted the privilege of "mining and digging in our Realm of England for allom and copperas." What Devoz accomplished is not recorded, but the first alum manufacture on a considerable scale seems to have been in Yorkshire, by one Thomas Chaloner (about 1608), who was supposed to have seduced workmen from the Pope's alum works at Tolfa, for which he was duly cursed with all the weight of the Pope and Church. (Pennant, Tour of Scotland, 1786).
[Pg 572][11]The term for vitriol used by the Roman authors, followed by Agricola, isatramentum sutorium, literally shoemaker's blacking, the term no doubt arising from its ancient (and modern) use for blackening leather. The Greek term waschalcanthon. The term "vitriol" seems first to appear in Albertus Magnus (De Mineralibus,LiberV.), who died in 1280, where he uses the expression "atramentum viride a quibusdam vitreolum vocatur." Agricola (De Nat. Foss., p. 213) states, "In recent years the namevitriolumhas been given to it." The first adequate description of vitriol is by Dioscorides (V., 76), as follows:—"Vitriol (chalcanthon) is of one genus, and is a solidified liquid, but it has three different species. One is formed from the liquids which trickle down drop by drop and congeal in certain mines; therefore those who work in the Cyprian mines call itstalactis. Petesius calls this kindpinarion. The second kind is that which collects in certain caverns; afterward it is poured into trenches, where it congeals, whence it derives its namepēctos. The third kind is calledhephthonand is mostly made in Spain; it has a beautiful colour but is weak. The manner of preparing it is as follows: dissolving it in water, they boil it, and then they transfer it to cisterns and leave it to settle. After a certain number of days it congeals and separates into many small pieces, having the form of dice, which stick together like grapes. The most valued is blue, heavy, dense, and translucent." Pliny (XXXIV., 32) says:—"By the name which they have given to it, the Greeks indicate the similar nature of copper andatramentum sutorium, for they call itchalcanthon. There is no substance of an equally miraculous nature. It is made in Spain from wells of this kind of water. This water is boiled with an equal quantity of pure water, and is then poured into wooden tanks (fish ponds). Across these tanks there are fixed beams, to which hang cords stretched by little stones. Upon these cords adheres thelimus(Agricola's 'juice') in drops of a vitreous appearance, somewhat resembling a bunch of grapes. After removal, it is dried for thirty days. It is of a blue colour, and of a brilliant lustre, and is very like glass. Its solution is the blacking used for colouring leather.Chalcanthonis made in many other ways: its kind of earth is sometimes dug from ditches, from the sides of which exude drops, which solidify by the winter frosts into icicles, calledstalagmia, and there is none more pure. When its colour is nearly white, with a slight tinge of violet, it is calledleukoïon. It is also made in rock basins, the rain water collecting thelimusinto them, where it becomes hardened. It is also made in the same way as salt by the intense heat of the sun. Hence it is that some distinguish two kinds, the mineral and the artificial; the latter being paler than the former and as much inferior to it in quality as it is in colour."While Pliny gives prominence to blue vitriol, his solution for colouring leather must have been the iron sulphate. There can be no doubt from the above, however, that both iron and copper sulphates were known to the Ancients. From the methods for making vitriol given here inDe Re Metallica, it is evident that only the iron sulphate would be produced, for the introduction of iron strips into the vats would effectually precipitate any copper. It is our belief that generally throughout this work, the iron sulphate is meant by the termatramentum sutorium. InDe Natura Fossilium(p. 213-15) Agricola gives three varieties ofatramentum sutorium,—viride,caeruleum, andcandidum,i.e., green, blue, and white. Thus the first mention of white vitriol (zinc sulphate) appears to be due to him, and he states further (p. 213): "A white sort is found, especially at Goslar, in the shape of icicles, transparent like crystals." And on p. 215: "Since I have explained the nature of vitriol and its relatives, which are obtained from cupriferous pyrites, I will next speak of an acrid solidified juice which commonly comes fromcadmia. It is found at Annaberg in the tunnel driven to the Saint Otto mine; it is hard and white, and so acrid that it kills mice, crickets, and every kind of animal. However, that feathery substance which oozes out from the mountain rocks and the thick substance found hanging in tunnels and caves from which saltpetre is made, while frequently acrid, does not come fromcadmia." Dana (Syst. of Min., p. 939) identifies this asGoslarite—native zinc sulphate. It does not appear, however, that artificial zinc vitriol was made in Agricola's time. Schlüter (Huette-Werken, Braunschweig 1738, p. 597) states it to have been made for the first time at Rammelsberg about 1570.[Pg 573]It is desirable here to enquire into the nature of the substances given by all of the old mineralogists under the Latinized Greek termschalcitis,misy,sory, andmelanteria. The first mention of these minerals is in Dioscorides, who (V., 75-77) says: "The bestchalcitisis like copper. It is friable, not stony, and is intersected by long brilliant veins....Misyis obtained from Cyprus; it should have the appearance of gold, be hard, and when pulverised it should have the colour of gold and sparkle like stars. It has the same properties aschalcitis.... The best is from Egypt.... One kind ofmelanteriacongeals like salt in the entries to copper mines. The other kind is earthy and appears on the surface of the aforesaid mines. It is found in the mines of Cilicia and other regions. The best has the colour of sulphur, is smooth, pure, homogenous, and upon contact with water immediately becomes black.... Those who considersoryto be the same asmelanteria, err greatly.Soryis a species of its own, though it is not dissimilar. The smell ofsoryis oppressive and provokes nausea. It is found in Egypt and in other regions, as Libya, Spain, and Cyprus. The best is from Egypt, and when broken is black, porous, greasy, and astringent." Pliny (XXXIV., 29-31) says:—"That is calledchalcitisfrom which, as well as itself copper (?) is extracted by heat. It differs fromcadmiain that this is obtained from rocks near the surface, while that is taken from rocks below the surface. Alsochalcitisis immediately friable, being naturally so soft as to appear like compressed wool. There is also this other distinction;chalcitiscontains three other substances, copper,misy, andsory. Of each of these we shall speak in their appropriate places. It contains elongated copper veins. The most approved kind is of the colour of honey; it is streaked with fine sinuous veins and is friable and not stony. It is considered most valuable when fresh.... Thesoryof Egypt is the most esteemed, being much superior to that of Cyprus, Spain, and Africa; although some prefer thesoryfrom Cyprus for affections of the eyes. But from whatever nation it comes, the best is that which has the strongest odour, and which, when ground up, becomes greasy, black, and spongy. It is a substance so unpleasant to the stomach that some persons are nauseated by its smell. Some say thatmisyis made by the burning of stones in trenches, its fine yellow powder being mixed with the ashes of pine-wood. The truth is, as I said above, that though obtained from the stone, it is already made and in solid masses, which require force to detach them. The best comes from the works of Cyprus, its characteristics being that when broken it sparkles like gold, and when ground it presents a sandy appearance, but on the contrary, if heated, it is similar tochalcitis.Misyis used in refining gold...."Agricola's views on the subject appear inDe Natura Fossilium. He says (p. 212):—"The cupriferous pyrites (pyrites aerosus) calledchalcitisis the mother and cause ofsory—which is likewise known as minevitriol(atramentum metallicum)—andmelanteria. These in turn yield vitriol and such related things. This may be seen especially at Goslar, where the nodular lumps of dark grey colour are called vitriol stone (lapis atramenti). In the centre of them is found greyish pyrites, almost dissolved, the size of a walnut. It is enclosed on all sides, sometimes bysory, sometimes bymelanteria. From them start little veinlets of greenish vitriol which spread all over it, presenting somewhat the appearance of hairs extending in all directions and cohering together.... There are five species of this solidified juice,melanteria,sory,chalcitis,misy, and vitriol. Sometimes many are found in one place, sometimes all of them, for one originates from the other. From pyrites, which is, as one might say, the root of all these juices, originates the above-mentionedsoryandmelanteria. Fromsory,chalcitis, andmelanteriaoriginate the various kinds of vitriol....Sory,melanteria,chalcitis, andmisyare always native; vitriol alone is either native or artificial. From them vitriol effloresces white, and sometimes green or blue.Misyeffloresces not only fromsory,melanteria, andchalcitis, but also from all the vitriols, artificial as well as natural....Soryandmelanteriadiffer somewhat from the others, but they are of the same colours, grey and black; butchalcitisis red and copper-coloured;misyis yellow or gold-coloured. All these native varieties have the odour of lightning (brimstone), butsoryis the most powerful. The feathery vitriol is soft and fine and hair-like, andmelanteriahas the appearance of wool and it has a similarity to salt; all these are rare and light;sory,chalcitis, andmisyhave the following relations.Sorybecause of its density has the hardness of stone, although its texture is very coarse.Misyhas a very fine texture.Chalcitisis between the two; because of its roughness and strong odour it differs frommelanteria, although they do not differ in colour. The vitriols, whether natural or artificial, are hard and dense ... as regarding shape,sory,chalcitis,misy, andmelanteriaare nodular, butsoryis occasionally porous, which is peculiar to it.[Pg 574]Misywhen it effloresces in no great quantity from the others is like a kind of pollen, otherwise it is nodular.Melanteriasometimes resembles wool, sometimes salt."The sum and substance, therefore, appears to be thatmisyis a yellowish material, possibly ochre, andsorya blackish stone, both impregnated with vitriol.Chalcitisis a partially decomposed pyrites; andmelanteriais no doubt native vitriol. From this last term comes the modernmelanterite, native hydrous ferrous sulphate. Dana (System of Mineralogy, p. 964) considersmisyto be in partcopiapite—basic ferric sulphate—but any such part would not come under Agricola's objection to it as a source of vitriol. The disabilities of this andchalcitismay, however, be due to their copper content.
[Pg 572][11]The term for vitriol used by the Roman authors, followed by Agricola, isatramentum sutorium, literally shoemaker's blacking, the term no doubt arising from its ancient (and modern) use for blackening leather. The Greek term waschalcanthon. The term "vitriol" seems first to appear in Albertus Magnus (De Mineralibus,LiberV.), who died in 1280, where he uses the expression "atramentum viride a quibusdam vitreolum vocatur." Agricola (De Nat. Foss., p. 213) states, "In recent years the namevitriolumhas been given to it." The first adequate description of vitriol is by Dioscorides (V., 76), as follows:—"Vitriol (chalcanthon) is of one genus, and is a solidified liquid, but it has three different species. One is formed from the liquids which trickle down drop by drop and congeal in certain mines; therefore those who work in the Cyprian mines call itstalactis. Petesius calls this kindpinarion. The second kind is that which collects in certain caverns; afterward it is poured into trenches, where it congeals, whence it derives its namepēctos. The third kind is calledhephthonand is mostly made in Spain; it has a beautiful colour but is weak. The manner of preparing it is as follows: dissolving it in water, they boil it, and then they transfer it to cisterns and leave it to settle. After a certain number of days it congeals and separates into many small pieces, having the form of dice, which stick together like grapes. The most valued is blue, heavy, dense, and translucent." Pliny (XXXIV., 32) says:—"By the name which they have given to it, the Greeks indicate the similar nature of copper andatramentum sutorium, for they call itchalcanthon. There is no substance of an equally miraculous nature. It is made in Spain from wells of this kind of water. This water is boiled with an equal quantity of pure water, and is then poured into wooden tanks (fish ponds). Across these tanks there are fixed beams, to which hang cords stretched by little stones. Upon these cords adheres thelimus(Agricola's 'juice') in drops of a vitreous appearance, somewhat resembling a bunch of grapes. After removal, it is dried for thirty days. It is of a blue colour, and of a brilliant lustre, and is very like glass. Its solution is the blacking used for colouring leather.Chalcanthonis made in many other ways: its kind of earth is sometimes dug from ditches, from the sides of which exude drops, which solidify by the winter frosts into icicles, calledstalagmia, and there is none more pure. When its colour is nearly white, with a slight tinge of violet, it is calledleukoïon. It is also made in rock basins, the rain water collecting thelimusinto them, where it becomes hardened. It is also made in the same way as salt by the intense heat of the sun. Hence it is that some distinguish two kinds, the mineral and the artificial; the latter being paler than the former and as much inferior to it in quality as it is in colour."
While Pliny gives prominence to blue vitriol, his solution for colouring leather must have been the iron sulphate. There can be no doubt from the above, however, that both iron and copper sulphates were known to the Ancients. From the methods for making vitriol given here inDe Re Metallica, it is evident that only the iron sulphate would be produced, for the introduction of iron strips into the vats would effectually precipitate any copper. It is our belief that generally throughout this work, the iron sulphate is meant by the termatramentum sutorium. InDe Natura Fossilium(p. 213-15) Agricola gives three varieties ofatramentum sutorium,—viride,caeruleum, andcandidum,i.e., green, blue, and white. Thus the first mention of white vitriol (zinc sulphate) appears to be due to him, and he states further (p. 213): "A white sort is found, especially at Goslar, in the shape of icicles, transparent like crystals." And on p. 215: "Since I have explained the nature of vitriol and its relatives, which are obtained from cupriferous pyrites, I will next speak of an acrid solidified juice which commonly comes fromcadmia. It is found at Annaberg in the tunnel driven to the Saint Otto mine; it is hard and white, and so acrid that it kills mice, crickets, and every kind of animal. However, that feathery substance which oozes out from the mountain rocks and the thick substance found hanging in tunnels and caves from which saltpetre is made, while frequently acrid, does not come fromcadmia." Dana (Syst. of Min., p. 939) identifies this asGoslarite—native zinc sulphate. It does not appear, however, that artificial zinc vitriol was made in Agricola's time. Schlüter (Huette-Werken, Braunschweig 1738, p. 597) states it to have been made for the first time at Rammelsberg about 1570.
[Pg 573]It is desirable here to enquire into the nature of the substances given by all of the old mineralogists under the Latinized Greek termschalcitis,misy,sory, andmelanteria. The first mention of these minerals is in Dioscorides, who (V., 75-77) says: "The bestchalcitisis like copper. It is friable, not stony, and is intersected by long brilliant veins....Misyis obtained from Cyprus; it should have the appearance of gold, be hard, and when pulverised it should have the colour of gold and sparkle like stars. It has the same properties aschalcitis.... The best is from Egypt.... One kind ofmelanteriacongeals like salt in the entries to copper mines. The other kind is earthy and appears on the surface of the aforesaid mines. It is found in the mines of Cilicia and other regions. The best has the colour of sulphur, is smooth, pure, homogenous, and upon contact with water immediately becomes black.... Those who considersoryto be the same asmelanteria, err greatly.Soryis a species of its own, though it is not dissimilar. The smell ofsoryis oppressive and provokes nausea. It is found in Egypt and in other regions, as Libya, Spain, and Cyprus. The best is from Egypt, and when broken is black, porous, greasy, and astringent." Pliny (XXXIV., 29-31) says:—"That is calledchalcitisfrom which, as well as itself copper (?) is extracted by heat. It differs fromcadmiain that this is obtained from rocks near the surface, while that is taken from rocks below the surface. Alsochalcitisis immediately friable, being naturally so soft as to appear like compressed wool. There is also this other distinction;chalcitiscontains three other substances, copper,misy, andsory. Of each of these we shall speak in their appropriate places. It contains elongated copper veins. The most approved kind is of the colour of honey; it is streaked with fine sinuous veins and is friable and not stony. It is considered most valuable when fresh.... Thesoryof Egypt is the most esteemed, being much superior to that of Cyprus, Spain, and Africa; although some prefer thesoryfrom Cyprus for affections of the eyes. But from whatever nation it comes, the best is that which has the strongest odour, and which, when ground up, becomes greasy, black, and spongy. It is a substance so unpleasant to the stomach that some persons are nauseated by its smell. Some say thatmisyis made by the burning of stones in trenches, its fine yellow powder being mixed with the ashes of pine-wood. The truth is, as I said above, that though obtained from the stone, it is already made and in solid masses, which require force to detach them. The best comes from the works of Cyprus, its characteristics being that when broken it sparkles like gold, and when ground it presents a sandy appearance, but on the contrary, if heated, it is similar tochalcitis.Misyis used in refining gold...."
Agricola's views on the subject appear inDe Natura Fossilium. He says (p. 212):—"The cupriferous pyrites (pyrites aerosus) calledchalcitisis the mother and cause ofsory—which is likewise known as minevitriol(atramentum metallicum)—andmelanteria. These in turn yield vitriol and such related things. This may be seen especially at Goslar, where the nodular lumps of dark grey colour are called vitriol stone (lapis atramenti). In the centre of them is found greyish pyrites, almost dissolved, the size of a walnut. It is enclosed on all sides, sometimes bysory, sometimes bymelanteria. From them start little veinlets of greenish vitriol which spread all over it, presenting somewhat the appearance of hairs extending in all directions and cohering together.... There are five species of this solidified juice,melanteria,sory,chalcitis,misy, and vitriol. Sometimes many are found in one place, sometimes all of them, for one originates from the other. From pyrites, which is, as one might say, the root of all these juices, originates the above-mentionedsoryandmelanteria. Fromsory,chalcitis, andmelanteriaoriginate the various kinds of vitriol....Sory,melanteria,chalcitis, andmisyare always native; vitriol alone is either native or artificial. From them vitriol effloresces white, and sometimes green or blue.Misyeffloresces not only fromsory,melanteria, andchalcitis, but also from all the vitriols, artificial as well as natural....Soryandmelanteriadiffer somewhat from the others, but they are of the same colours, grey and black; butchalcitisis red and copper-coloured;misyis yellow or gold-coloured. All these native varieties have the odour of lightning (brimstone), butsoryis the most powerful. The feathery vitriol is soft and fine and hair-like, andmelanteriahas the appearance of wool and it has a similarity to salt; all these are rare and light;sory,chalcitis, andmisyhave the following relations.Sorybecause of its density has the hardness of stone, although its texture is very coarse.Misyhas a very fine texture.Chalcitisis between the two; because of its roughness and strong odour it differs frommelanteria, although they do not differ in colour. The vitriols, whether natural or artificial, are hard and dense ... as regarding shape,sory,chalcitis,misy, andmelanteriaare nodular, butsoryis occasionally porous, which is peculiar to it.[Pg 574]Misywhen it effloresces in no great quantity from the others is like a kind of pollen, otherwise it is nodular.Melanteriasometimes resembles wool, sometimes salt."
The sum and substance, therefore, appears to be thatmisyis a yellowish material, possibly ochre, andsorya blackish stone, both impregnated with vitriol.Chalcitisis a partially decomposed pyrites; andmelanteriais no doubt native vitriol. From this last term comes the modernmelanterite, native hydrous ferrous sulphate. Dana (System of Mineralogy, p. 964) considersmisyto be in partcopiapite—basic ferric sulphate—but any such part would not come under Agricola's objection to it as a source of vitriol. The disabilities of this andchalcitismay, however, be due to their copper content.
[Pg 578][12]Agricola (De Nat. Fos., 221) says:—"There is a species of artificial sulphur made from sulphur and iron hammer-scales, melted together and poured into moulds. This, because it heals scabs of horses, is generally calledcaballinum." It is difficult to believe such a combination was other than iron sulphide, but it is equally difficult to understand how it was serviceable for this purpose.
[Pg 578][12]Agricola (De Nat. Fos., 221) says:—"There is a species of artificial sulphur made from sulphur and iron hammer-scales, melted together and poured into moulds. This, because it heals scabs of horses, is generally calledcaballinum." It is difficult to believe such a combination was other than iron sulphide, but it is equally difficult to understand how it was serviceable for this purpose.
[13]Inasmuch as pyrites is discussed in the next paragraph, the material of the first distillation appears to be native sulphur. Until the receiving pots became heated above the melting point of the sulphur, the product would be "flowers of sulphur," and not the wax-like[Pg 579]product. The equipment described for pyrites in the next paragraph would be obviously useful only for coarse material.But little can be said on the history of sulphur; it is mentioned often enough in the Bible and also by Homer (Od.XXII., 481). The Greeks apparently knew how to refine it, although neither Dioscorides nor Pliny specifically describes such an operation. Agricola says (De Nat. Fos., 220): "Sulphur is of two kinds; the mineral, which the Latins callvivum, and the Greeksapyron, which means 'not exposed to the fire' (ignem non expertum) as rightly interpreted by Celsius; and the artificial, called by the Greekspepyromenon, that is, 'exposed to the fire.'" InBook X., the expressionsulfur ignem non expertumfrequently appears, no doubt in Agricola's mind for native sulphur, although it is quite possible that the Greek distinction was between "flowers" of sulphur and the "wax-like" variety.
[13]Inasmuch as pyrites is discussed in the next paragraph, the material of the first distillation appears to be native sulphur. Until the receiving pots became heated above the melting point of the sulphur, the product would be "flowers of sulphur," and not the wax-like[Pg 579]product. The equipment described for pyrites in the next paragraph would be obviously useful only for coarse material.
But little can be said on the history of sulphur; it is mentioned often enough in the Bible and also by Homer (Od.XXII., 481). The Greeks apparently knew how to refine it, although neither Dioscorides nor Pliny specifically describes such an operation. Agricola says (De Nat. Fos., 220): "Sulphur is of two kinds; the mineral, which the Latins callvivum, and the Greeksapyron, which means 'not exposed to the fire' (ignem non expertum) as rightly interpreted by Celsius; and the artificial, called by the Greekspepyromenon, that is, 'exposed to the fire.'" InBook X., the expressionsulfur ignem non expertumfrequently appears, no doubt in Agricola's mind for native sulphur, although it is quite possible that the Greek distinction was between "flowers" of sulphur and the "wax-like" variety.
[Pg 581][14]The substances referred to under the namesbitumen,asphalt,maltha,naphtha,petroleum,rock-oil, etc., have been known and used from most ancient times, and much of our modern nomenclature is of actual Greek and Roman ancestry. These peoples distinguished three related substances,—the Greekasphaltosand Romanbitumenfor the hard material,—Greekpissasphaltosand Romanmalthafor the viscous, pitchy variety—and occasionally the Greeknaphthaand Romannaphthafor petroleum proper, although it is often enough referred to as liquidbitumenor liquidasphaltos. The termpetroleumapparently first appears in Agricola'sDe Natura Fossilium(p. 222), where he says the "oil of bitumen ... now[Pg 582]calledpetroleum." Bitumen was used by the Egyptians for embalming from pre-historic times,i.e., prior to 5000B.C., the term "mummy" arising from the Persian word for bitumen,mumiai. It is mentioned in the tribute from Babylonia to ThotmesIII., who lived about 1500B.C.(Wilkinson, Ancient EgyptiansI., p. 397). The Egyptians, however, did not need to go further afield than the Sinai Peninsula for abundant supplies. Bitumen is often cited as the real meaning of the "slime" mentioned in Genesis (XI., 3;XIV., 10), and used in building the Tower of Babel. There is no particular reason for this assumption, except the general association of Babel, Babylon, and Bitumen. However, the Hebrew wordsiftfor pitch or bitumen does occur as the cement used for Moses's bulrush cradle (ExodusII., 3), and Moses is generally accounted about 1300B.C.Other attempts to connect Biblical reference to petroleum and bitumen revolve around JobXXIX., 6, Deut.XXXII., 13, MaccabeesII.,I, 18, MatthewV., 13, but all require an unnecessary strain on the imagination.The plentiful occurrence of bitumen throughout Asia Minor, and particularly in the Valley of the Euphrates and in Persia, is the subject of innumerable references by writers from Herodotus (484-424B.C.) down to the author of the company prospectus of recent months. Herodotus (I., 179) and Diodorus Siculus (I) state that the walls of Babylon were mortared with bitumen—a fact partially corroborated by modern investigation. The following[Pg 583]statement by Herodotus (VI., 119) is probably the source from which Pliny drew the information which Agricola quotes above. In referring to a well at Ardericca, a place about 40 miles from ancient Susa, in Persia, Herodotus says:—"For from the well they get bitumen, salt, and oil, procuring it in the way that I will now describe: they draw with a swipe, and instead of a bucket they make use of the half of a wine-skin; with this the man dips and, after drawing, pours the liquid into a reservoir, wherefrom it passes into another, and there takes three different shapes. The salt and bitumen forthwith collect and harden, while the oil is drawn off into casks. It is called by the Persiansrhadinace, is black, and has an unpleasant smell." (Rawlinson's Trans.III., p. 409). The statement from Pliny (XXXI., 39) here referred to by Agricola, reads:—"It (salt) is made from water of wells poured into salt-pans. At Babylon the first condensed is a bituminous liquid like oil which is burned in lamps. When this is taken off, salt is found beneath. In Cappadocia also the water from both wells and springs is poured into salt-pans." When petroleum began to be used as an illuminant it is impossible to say. A passage in Aristotle'sDe Mirabilibus(127) is often quoted, but in reality it refers only to a burning spring, a phenomenon noted by many writers, but from which to its practical use is not a great step. The first really definite statement as to the use of petroleum as an[Pg 584]illuminant is Strabo's quotation (XVI., 1, 15) from Posidonius: "Asphaltus is found in great abundance in Babylonia. Eratosthenes describes it as follows:—The liquidasphaltus, which is callednaphtha, is found in Susa; the dry kind, which can be made solid, in Babylonia. There is a spring of it near the Euphrates.... Others say that the liquid kind is also found in Babylonia.... The liquid kind, callednaphtha, is of a singular nature. When it is brought near the fire, the fire catches it.... Posidonius says that there are springs ofnaphthain Babylonia, some of which produce white, others blacknaphtha; the first of these, I mean whitenaphtha, which attracts flame, is liquid sulphur; the second or blacknaphthais liquidasphaltus, and is burnt in lamps instead of oil." (Hamilton's Translation, Vol.III., p. 151). Eratosthenes lived about 200B.C., and Posidonius about 100 years later. Dioscorides (I., 83), after discussing the usual sources of bitumen says: "It is found in a liquid state in Agrigentum in Sicily, flowing on streams; they use it for lights in lanterns in place of oil. Those who call the Sicilian kind oil are under a delusion, for it is agreed that it is a kind of liquid bitumen." Pliny adds nothing much new to the above quotations, except in regard to these same springs (XXXV., 51) that "The inhabitants collect it on the panicles of reeds, to which it quickly adheres and they use it for burning in lamps instead of oil." Agricola (De Natura Fossilium, BookIV.) classifies petroleum, coal, jet, and obsidian, camphor, and amber as varieties of bitumen, and devotes much space to the refutation of the claims that the last two are of vegetable origin.
[Pg 581][14]The substances referred to under the namesbitumen,asphalt,maltha,naphtha,petroleum,rock-oil, etc., have been known and used from most ancient times, and much of our modern nomenclature is of actual Greek and Roman ancestry. These peoples distinguished three related substances,—the Greekasphaltosand Romanbitumenfor the hard material,—Greekpissasphaltosand Romanmalthafor the viscous, pitchy variety—and occasionally the Greeknaphthaand Romannaphthafor petroleum proper, although it is often enough referred to as liquidbitumenor liquidasphaltos. The termpetroleumapparently first appears in Agricola'sDe Natura Fossilium(p. 222), where he says the "oil of bitumen ... now[Pg 582]calledpetroleum." Bitumen was used by the Egyptians for embalming from pre-historic times,i.e., prior to 5000B.C., the term "mummy" arising from the Persian word for bitumen,mumiai. It is mentioned in the tribute from Babylonia to ThotmesIII., who lived about 1500B.C.(Wilkinson, Ancient EgyptiansI., p. 397). The Egyptians, however, did not need to go further afield than the Sinai Peninsula for abundant supplies. Bitumen is often cited as the real meaning of the "slime" mentioned in Genesis (XI., 3;XIV., 10), and used in building the Tower of Babel. There is no particular reason for this assumption, except the general association of Babel, Babylon, and Bitumen. However, the Hebrew wordsiftfor pitch or bitumen does occur as the cement used for Moses's bulrush cradle (ExodusII., 3), and Moses is generally accounted about 1300B.C.Other attempts to connect Biblical reference to petroleum and bitumen revolve around JobXXIX., 6, Deut.XXXII., 13, MaccabeesII.,I, 18, MatthewV., 13, but all require an unnecessary strain on the imagination.
The plentiful occurrence of bitumen throughout Asia Minor, and particularly in the Valley of the Euphrates and in Persia, is the subject of innumerable references by writers from Herodotus (484-424B.C.) down to the author of the company prospectus of recent months. Herodotus (I., 179) and Diodorus Siculus (I) state that the walls of Babylon were mortared with bitumen—a fact partially corroborated by modern investigation. The following[Pg 583]statement by Herodotus (VI., 119) is probably the source from which Pliny drew the information which Agricola quotes above. In referring to a well at Ardericca, a place about 40 miles from ancient Susa, in Persia, Herodotus says:—"For from the well they get bitumen, salt, and oil, procuring it in the way that I will now describe: they draw with a swipe, and instead of a bucket they make use of the half of a wine-skin; with this the man dips and, after drawing, pours the liquid into a reservoir, wherefrom it passes into another, and there takes three different shapes. The salt and bitumen forthwith collect and harden, while the oil is drawn off into casks. It is called by the Persiansrhadinace, is black, and has an unpleasant smell." (Rawlinson's Trans.III., p. 409). The statement from Pliny (XXXI., 39) here referred to by Agricola, reads:—"It (salt) is made from water of wells poured into salt-pans. At Babylon the first condensed is a bituminous liquid like oil which is burned in lamps. When this is taken off, salt is found beneath. In Cappadocia also the water from both wells and springs is poured into salt-pans." When petroleum began to be used as an illuminant it is impossible to say. A passage in Aristotle'sDe Mirabilibus(127) is often quoted, but in reality it refers only to a burning spring, a phenomenon noted by many writers, but from which to its practical use is not a great step. The first really definite statement as to the use of petroleum as an[Pg 584]illuminant is Strabo's quotation (XVI., 1, 15) from Posidonius: "Asphaltus is found in great abundance in Babylonia. Eratosthenes describes it as follows:—The liquidasphaltus, which is callednaphtha, is found in Susa; the dry kind, which can be made solid, in Babylonia. There is a spring of it near the Euphrates.... Others say that the liquid kind is also found in Babylonia.... The liquid kind, callednaphtha, is of a singular nature. When it is brought near the fire, the fire catches it.... Posidonius says that there are springs ofnaphthain Babylonia, some of which produce white, others blacknaphtha; the first of these, I mean whitenaphtha, which attracts flame, is liquid sulphur; the second or blacknaphthais liquidasphaltus, and is burnt in lamps instead of oil." (Hamilton's Translation, Vol.III., p. 151). Eratosthenes lived about 200B.C., and Posidonius about 100 years later. Dioscorides (I., 83), after discussing the usual sources of bitumen says: "It is found in a liquid state in Agrigentum in Sicily, flowing on streams; they use it for lights in lanterns in place of oil. Those who call the Sicilian kind oil are under a delusion, for it is agreed that it is a kind of liquid bitumen." Pliny adds nothing much new to the above quotations, except in regard to these same springs (XXXV., 51) that "The inhabitants collect it on the panicles of reeds, to which it quickly adheres and they use it for burning in lamps instead of oil." Agricola (De Natura Fossilium, BookIV.) classifies petroleum, coal, jet, and obsidian, camphor, and amber as varieties of bitumen, and devotes much space to the refutation of the claims that the last two are of vegetable origin.
[15]Agricola (De Natura Fossilium, p. 215) in discussing substances which originate from copper, gives among them greenchrysocolla(as distinguished from borax, etc., seeNote 8 above), and says: "Nativechrysocollaoriginates in veins and veinlets, and is found mostly by itself like sand, or adhering to metallic substances, and when scraped off from this appears similar to its own sand. Occasionally it is so thin that very little can be scraped off. Or else it occurs in waters which, as I have said, wash these minerals, and afterward it settles as a powder. At Neusohl in the Carpathians, green water flowing from an ancient tunnel wears away thischrysocollawith it. The water is collected in thirty large reservoirs, where it deposits thechrysocollaas a sediment, which they collect every year and sell,"—as a pigment. This description of its occurrence would apply equally well to modernchrysocollaor to malachite. The solution from copper ores would deposit some sort of green incrustation, of carbonates mostly.
[15]Agricola (De Natura Fossilium, p. 215) in discussing substances which originate from copper, gives among them greenchrysocolla(as distinguished from borax, etc., seeNote 8 above), and says: "Nativechrysocollaoriginates in veins and veinlets, and is found mostly by itself like sand, or adhering to metallic substances, and when scraped off from this appears similar to its own sand. Occasionally it is so thin that very little can be scraped off. Or else it occurs in waters which, as I have said, wash these minerals, and afterward it settles as a powder. At Neusohl in the Carpathians, green water flowing from an ancient tunnel wears away thischrysocollawith it. The water is collected in thirty large reservoirs, where it deposits thechrysocollaas a sediment, which they collect every year and sell,"—as a pigment. This description of its occurrence would apply equally well to modernchrysocollaor to malachite. The solution from copper ores would deposit some sort of green incrustation, of carbonates mostly.
[Pg 585][16]The statement in Pliny (XXXVI., 66) to which Agricola refers is as follows: "Then as ingenuity was not content with the mixing ofnitrum, they began the addition oflapis[Pg 586]magnes, because of the belief that it attracts liquefied glass as well as iron. In a similar manner many kinds of brilliant stones began to be added to the melting, and then shells and fossil sand. Authors tell us that the glass of India is made of broken crystal, and in consequence nothing can compare with it. Light and dry wood is used for fusing,cyprium(copper?) andnitrumbeing added, particularlynitrumfrom Ophir etc."A great deal of discussion has arisen over this passage, in connection with what thislapis magnesreally was. Pliny (XXXVI., 25) describes the lodestone under this term, but also says: "There (in Ethiopia) also ishaematites magnes, a stone of blood colour, which shows a red colour if crushed, or of saffron. Thehaematiteshas not the same property of attracting iron asmagnes." Relying upon this sentence for an exception to the ordinary sort ofmagnes, and upon the impossible chemical reaction involved, most commentators have endeavoured to show that lodestone was not the substance meant by Pliny, but manganese, and thus they find here the first knowledge of this mineral. There can be little doubt that Pliny assumed it to be the lodestone, and Agricola also. Whether the latter had any independent knowledge on this point in glass-making or was merely quoting Pliny—which seems probable—we do not know. In any event, Biringuccio, whose work precededDe Re Metallicaby fifteen years, does definitely mention manganese in this connection. He dismisses this statement of Pliny with the remark (p. 37-38): "The Ancients wrote about lodestones, as Pliny states, and they mixed it together withnitrumin their first efforts to make glass." The following passage from this author (p. 36-37), however, is not only of interest in this connection, but also as possibly being the first specific mention of manganese under its own name. Moreover, it has been generally overlooked in the many discussions of the subject. "Of a similar nature (tozaffir) is also another mineral calledmanganese, which is found, besides in Germany, at the mountain of Viterbo in Tuscany ... it is the colour offerrigno scuro(iron slag?). In melting it one cannot obtain any metal ... but it gives a very fine colour to glass, so that the glass workers use it in their pigments to secure an azure colour.... It also has such a property that when put into melted glass it cleanses it and makes it white, even if it were green or yellow. In a hot fire it goes off in a vapour like lead, and turns into ashes."To enter competently into the discussion of the early history of glass-making would employ more space than can be given, and would lead but to a sterile end. It is certain that the art was pre-Grecian, and that the Egyptians were possessed of some knowledge of making and blowing it in the XI Dynasty (according to Petrie 3,500B.C.), the wall painting at Beni Hassen, which represents glass-blowing, being attributed to that period. The remains of a glass factory at Tel el Amarna are believed to be of the XVIII Dynasty. (Petrie, 1,500B.C.). The art reached a very high state of development among the Greeks and Romans. No discussion of this subject omits Pliny's well-known story (XXXVI, 65), which we also add: "The tradition is that a merchant ship laden withnitrumbeing moored at this place, the merchants were preparing their meal on the beach, and not having stones to prop up their pots, they used lumps ofnitrumfrom the ship, which fused and mixed with the sands of the shore, and there flowed streams of a new translucent liquid, and thus was the origin of glass."
[Pg 585][16]The statement in Pliny (XXXVI., 66) to which Agricola refers is as follows: "Then as ingenuity was not content with the mixing ofnitrum, they began the addition oflapis[Pg 586]magnes, because of the belief that it attracts liquefied glass as well as iron. In a similar manner many kinds of brilliant stones began to be added to the melting, and then shells and fossil sand. Authors tell us that the glass of India is made of broken crystal, and in consequence nothing can compare with it. Light and dry wood is used for fusing,cyprium(copper?) andnitrumbeing added, particularlynitrumfrom Ophir etc."
A great deal of discussion has arisen over this passage, in connection with what thislapis magnesreally was. Pliny (XXXVI., 25) describes the lodestone under this term, but also says: "There (in Ethiopia) also ishaematites magnes, a stone of blood colour, which shows a red colour if crushed, or of saffron. Thehaematiteshas not the same property of attracting iron asmagnes." Relying upon this sentence for an exception to the ordinary sort ofmagnes, and upon the impossible chemical reaction involved, most commentators have endeavoured to show that lodestone was not the substance meant by Pliny, but manganese, and thus they find here the first knowledge of this mineral. There can be little doubt that Pliny assumed it to be the lodestone, and Agricola also. Whether the latter had any independent knowledge on this point in glass-making or was merely quoting Pliny—which seems probable—we do not know. In any event, Biringuccio, whose work precededDe Re Metallicaby fifteen years, does definitely mention manganese in this connection. He dismisses this statement of Pliny with the remark (p. 37-38): "The Ancients wrote about lodestones, as Pliny states, and they mixed it together withnitrumin their first efforts to make glass." The following passage from this author (p. 36-37), however, is not only of interest in this connection, but also as possibly being the first specific mention of manganese under its own name. Moreover, it has been generally overlooked in the many discussions of the subject. "Of a similar nature (tozaffir) is also another mineral calledmanganese, which is found, besides in Germany, at the mountain of Viterbo in Tuscany ... it is the colour offerrigno scuro(iron slag?). In melting it one cannot obtain any metal ... but it gives a very fine colour to glass, so that the glass workers use it in their pigments to secure an azure colour.... It also has such a property that when put into melted glass it cleanses it and makes it white, even if it were green or yellow. In a hot fire it goes off in a vapour like lead, and turns into ashes."
To enter competently into the discussion of the early history of glass-making would employ more space than can be given, and would lead but to a sterile end. It is certain that the art was pre-Grecian, and that the Egyptians were possessed of some knowledge of making and blowing it in the XI Dynasty (according to Petrie 3,500B.C.), the wall painting at Beni Hassen, which represents glass-blowing, being attributed to that period. The remains of a glass factory at Tel el Amarna are believed to be of the XVIII Dynasty. (Petrie, 1,500B.C.). The art reached a very high state of development among the Greeks and Romans. No discussion of this subject omits Pliny's well-known story (XXXVI, 65), which we also add: "The tradition is that a merchant ship laden withnitrumbeing moored at this place, the merchants were preparing their meal on the beach, and not having stones to prop up their pots, they used lumps ofnitrumfrom the ship, which fused and mixed with the sands of the shore, and there flowed streams of a new translucent liquid, and thus was the origin of glass."