Fig. 1.—Wasting River Shore due to Tidal Flow.Fig. 1.—Wasting River Shore due to Tidal Flow.
It has been suggested that rudely chipped implements, when found on the gravelly shore of the river, have fallen out from the bank and rolled down from where they had long been lying. Thisis not at all improbable; but how does this modernize the object, when the gravel extends quite to the surface? The pebbles and bowlders at the top of the bank are clearly as much a part of the deposit as are those at its base, and while the surface may be—is, in fact—less ancient than the deeper gravels, still they can not be dissociated; and it is a significant fact that we find, on the gravel at the foot of the bluff or other exposure, only the rude argillite objects at the water's edge or on the flat laid bare at low tide, and not a general assortment of the Indian's handiwork, including pottery; and we must not overlook the fact that the "gravel-bed" implements bear evidence of all the conditions to which the gravel itself has been subjected—this one stained by manganese, that incrusted with limonite; this fresh as the day it was chipped, because lost in sand and water and not subsequently exposed to the atmosphere; that buried and unearthed, rolled, scratched, and water-worn until much of its artificiality has disappeared. The history of almost every specimen is written upon it, and not one tells such a story as has been told about it by the advocates of the "Indian-reject" theory.
Much has been written on the natural history of the gravel that is so marked a feature of the river valley, particularly at the headof tide water, and almost every essay differs in more or less degree from its fellows in the matter of the gravel's age as a well-defined deposit. Its origin no one can question, nor the agencies by which it was brought to where we now find it. Ice and water did the work, nor have they ceased entirely to add to the bulk transported in strictly glacial times—perhaps it were better to say in superlatively glacial time, as the river even now can be positively glacial upon occasion, as Fig. 2 demonstrates. The main channel has often been completely blocked with ice and the water forced into new directions and spread over the lowlands or flats, which it denudes of its surface soil, and once within recent years the stream found an old channel, deepened it, and for a time threatened to leave a flourishing riverside town an inland one. Ice accumulated in this way year after year must necessarily affect the river's banks, and yet the extent of "damage" is trifling usually, in comparison with that of the water, particularly when agitated by passing steamboats or violent winds; and now, too, the ice of our present winters does not transport coarse pebbles to any significant extent. I am convinced of this since the examination I gave acres of ice, when the river was gorged with it, some years ago. It was possible to walk for miles over the ice, as shown in Fig. 2, and to see it under exceedingly favorable circumstances, and a most careful search failed to reveal a stone larger than a pigeon's egg incased in this ice, which was all gently floated from far up the stream and stranded here; and where piled up upon the shores it usually remains until melted, and really acts as armor plate, protecting the ground from abrasion when the floods incident to the "break-up" prevail. Such are the present-day considerations, and they have a direct bearing upon the question of man's antiquity here because, first, the river valley has not varied for hundreds of years, except in becoming wider, the low shores receding, and the stream becoming broader and more shallow. In earliest Indian times the river was subject to freshets and ice gorges as now, but never did the water become so dammed up as to overflow the broad plateaus, areas of glacial gravel, that at the close of the Glacial period were within the boundary of the river. The Delaware was a very different stream then—crescendofor thousands of years, anddiminuendofor thousands since—until now it barely hints at what once was. But not even in the height of its glacial activity was the climate so severe that the waters contained no fish, nor the forests of the high surrounding hills harbored no game. Never was it as bleak as the arctic region of to-day, and as man maintains a footing there, why should he not have done so here, where life was ever more easily sustained? True; but did he live here in glacial time?
Fig. 2.—Ice-Gorged River.Fig. 2.—Ice-Gorged River.Reproducing on a small scale the conditions of the Glacial epoch.
It has been stated in the most positive manner, which only positive evidence could warrant, that so-called paleolithic implements have not been foundin situin gravel deposits at a distance from the river, and such,if there were such, as appeared to be in the gravel, were recent intrusions. This statement, in its several parts and its entirety, is absolutely incorrect, and no excuse can be offered for its publication. It is to be explained, however, because avowedly predetermined. Wherever the glacial gravel of the Delaware tide-water region is found, there paleolithic implements occur, as they also do on and in the surface of areas beyond the gravel boundary. We accept, notwithstanding the unscientific source of the suggestion, the statement that post-glacial floods inhumed all traces of man found beneath the superficial soils, and find that, if these traces are considered in that light, some mysterious power was behind the senseless flood, and always buried argillite paleolithic implements far down in the gravel, and then selected argillite artifacts of more specialized forms for the overlying sands and reserved the pottery and jasper arrow points for the vegetation-sustaining soil. This, as stated, is absurd, but such is the order of occurrence of the traces of early man in the upland fields, and these are to beconsidered carefully before a final conclusion can be reached. The broad, elevated plateau extending eastward from the present bank of the river offers facilities for studying the evidences of man's occupancy in this region such as are to be found in few localities. The principal reason for this is that almost no local disturbance has occurred since the original deposition of the sand that overlies the gravel and underlies the soil. The natural history of these underlying sands has recently received a good deal of attention, because, unlike the deeper gravels, there is perfect accord as to the occurrences therein of artificially chipped objects; and the suggestion that they are of intrusive origin being set aside as untenable, the geologists are now divided on the question whether the sand is wind-blown, a modified dune, and so not necessarily old even in years, or the result of intermitting overflow of water, usually carrying a considerable amount of sand and often heavy with washings from some distant clay bank. The objections to the "eolian" theory are that pebbles and bowlders, even of considerable weight, are scattered at all elevations through the sand, and these pebbles, as a rule, do not present any evidence of exposure to eroding sands, but are smooth and glassy, or the typical water-worn pebbles of a brook or the river bed, and more significant is the fact that the sands themselves are of different degrees of fineness, layer upon layer, and are nowhere clean or free from clay; and finally the thin layers of clay are clearly continuous over such extensive areas that in no sense can they be called segregations of that material. On the other hand, a carefully instituted comparison of the sand from the surface of the field to its junction with the gravel proper shows its identity with a deposit made by water in comparatively recent times. No difference whatever could be detected. The sand dune, modified by rains and finally leveled to a plain, presents, in section, no such appearance as the sands that overlie the gravels of glacial origin. Without a scintilla of reason, however, many geologists declare that no deposit of sand can be of any geological significanceif it contains traces of man not clearly intrusive. The latter fact necessitates the former claim, all of which, I submit, is nonsense.
Fig. 3 illustrates how artificially chipped pebbles occur in this underlying sand. The upper portion shows the superficial soil removed to its point of contact with the sand. This is determined by the change of color from dark brown to light yellowish brown, and it is generally so very abrupt a change that no doubt arises as to where the soil ends and the sand begins. The sand proper is shown by the position of the object—the measuring rule and trowel. It will be noticed that the implement is lying flat, as such an object would almost necessarily be if transported by water, and notperpendicular, as would be the case if it had fallen down some root-hole, animal's or insect's burrow, or opening in the earth from any cause, and now obliterated.
Fig. 3.—Occurrence of an Argillite Implement in Glacial Stratified Sand.Fig. 3.—Occurrence of an Argillite Implement in Glacial Stratified Sand.
The presence of these artificial flakes, blades, and other forms of simple implements can only be explained by considering them as a constituent part of the containing bed, having been brought hither by the same agency that brought the sand, pebbles, and clay. When standing before a newly made section of this implement-bearing deposit it is easy to picture the slow progress of its accumulation. The broad plain has been subjected to overflow, now of water bearing only sand, and then of muddy water; now with current strong enough to roll small pebbles from some distant point, and then periods when the sun shone on the new deposit, dried it, and the loose sand was rippled by the wind. Floods of greater volume occasionally swept across the plain, and ice-incased pebbles were dropped upon its surface, and with this building up of the plateau to a higher level there were also brought to it traces of man's handiwork. Of this, I think, there can be no doubt now. Years ago I endeavored to show from the distribution of rude argillite implements of specialized forms, as arrow points and small blades, trimmed flakes and scrapers, that these objects were older, as a class, than jasper and quartz implements and weapons, and that pottery was made only in the rudest way before "flint" chipping—jasper and quartz—was established. The more exhaustively this subject was followed up, the proposition became more evidently true, and to-day it is unqualifiedly confirmed by the results obtained from systematically digging deeply over wide areas of country. The fact that argillite continued in use until the very last does not affect this conclusion.
As the high land, now forty or more feet above the river and beyond the reach of its floods of greatest magnitude, was once continually overflowed and gradually built up by the materials the water spread upon it, it is evident that the conditions were materially different when such things happened from what now obtains, and the whole configuration of the country to-day points to but the one conclusion: that these plateau-building floods occurred so long ago as when the river flowed at a higher level and possessed a greater transporting power than at present. This, it is true, was long after the coarse gravel and huge bowlders were transported from the hillsides of the upper valley, but it was before the river was confined to its present channel, and more significantly before what may be called the soil-making period, itself of long duration and the time of the Indian as such. Not an argillite chip from the sands beneath the soil but speaks of the distant day when this plateau was an almost barren plain, and man saw it, roamed over it, and perhaps dwelt upon it, when but the scantiest vegetation dotted its surface, and only upon the hills beyond its boundary were there trees and herbage.
Even if we consider the agency of the streams that now are but insignificant inflowing brooks in spreading, during their freshet stages, sand over level areas, we must still go back to a time when they were streams of infinitely greater magnitude than they have been for many centuries, and before, too, the Indian was a skilled chipper of jasper and a potter of taste, else why the absence of these products of his skill in the deeper sands? It matters not how we look at it, whether as geologists or archæologists, or whether it is all post-glacial, or the starting point is still so distant as ice-age activities, the sequence of events is unaffected. We still have paleolithicity in the gravel, argillite and the discovery of pottery synchronous with the deposition of the gravel-capping sand, and, lastly, the Indian.
The record is not a difficult one to read, and never has been, and the manifold attempts to modernize all traces of man on the eastern coast of North America can safely be relegated to the limbo of misdirected energy. Studied in the proper spirit and after the needful preliminary study of archæology as a whole, the student will find himself, when in the field—ever a more desirable place than the museum—face to face with evidences of an antiquity that is to be measured by centuries rather than by years.
By EDWARD RENOUF,
COLLEGIATE PROFESSOR OF CHEMISTRY, JOHNS HOPKINS UNIVERSITY.
It is now five years since the use of acetylene as an illuminant was suggested to the public, and it may be of interest to give a sketch of what has been done during this time, especially as it seems that with the year 1899 the tentative period which must characterize every new industry is in some respects passed, and a period of solid and well-directed industrial effort, backed by ample capital, has begun. The knowledge gained during this tentative period by the laboratory experiments of scientific men, and by the practical work of inventors and promoters, has made it possible for the industry to enter on its new phase. To understand its present and to foresee its future importance it is necessary briefly to review the work of the last years.
In May, 1892, Mr. Thomas Willson, a Canadian electrician, tried to make the metal calcium in an electric furnace in his works at Spray, North Carolina, by heating a mixture of lime and coal dust. He thought that the lime (calcium oxide) would act on the coal (carbon) to form calcium and carbon monoxide. He did not succeed ingetting calcium, but found in the furnace a brown, crystalline mass, which was decomposed by pouring water on it, yielding an inflammable gas. Willson is not a chemist, and he therefore sent specimens of the material to several men of science to determine its nature. It was shown to be calcium carbide, a compound of calcium and carbon, formed by the action of the carbon on the calcium oxide. The reaction expressed in chemical symbols is CaO + 3C = CaC2+ CO. The gas formed by the action of water was acetylene, a compound of carbon and hydrogen. The reaction is CaC2+ H2O = C2H2+ CaO; calcium carbide and water form acetylene and lime. If water enough is added, the lime is slaked, and slaked lime, or calcium hydroxide, Ca(OH2), is formed. Neither calcium carbide nor acetylene was a new discovery; acetylene was discovered by Edmund Davy in 1836, and its properties were studied by Berthelot in 1862. Impure calcium carbide was first made in 1862 by Wöhler, who described its decomposition by water into acetylene and lime. What was there new, then, in Willson's discovery? Two important facts: (1) He was the first to make carbide by a method applicable commercially; (2) he was the first to make crystalline carbide. Wöhler's carbide was impure and amorphous; Willson's, nearly pure and crystalline, so that he succeeded in obtaining United States patents for crystalline carbide, and, as all carbide made by commercial processes is crystalline, its manufacture is covered by Willson's patents.
In the same year, 1892, Prof. Henri Moissan, of Paris, announced the discovery of crystalline calcium carbide. Moissan's discovery, too, was an accidental one. He was reducing refractory metallic oxides in an electric furnace made of lime. At the close of the article in which he reports his work to the French Academy of Sciences (Comptes Rendus de l'Académie Française, vol. cxii, page 6, December 12, 1892) he refers in two lines to the formation of an ill-defined carbide of calcium by the action of the carbon electrodes on the lime of which his furnace was made.
As is common with most important inventions, there is a dispute as to the priority of making carbide by an electric furnace; and the wonder is, not that there is a dispute, but that there are so few claimants. A few words of explanation of the electric furnace will show why. The enormous heat of the electric furnace (2000° to 3000° C.) is caused by an electric arc, formed by currents playing between carbon electrodes; carbon is often used in the furnace processes; here we have one constituent of calcium carbide. Lime, the material for the other constituent, withstands heat better than any other common substance excepting magnesia; naturally, inventors would use it, as Moissan did, as a refractory lining to the furnace. Electric furnaces were not new. The conditions then were such that the discovery ofthe carbide was fairly forced on experimenters, and, as we have seen, the discoveries of Willson and Moissan were both accidental.
American priority was claimed by Willson, French priority by the friends of Moissan, German priority by Professor Borchers, of Aix-la-Chapelle. Fortunately for Willson, among those to whom he had sent specimens of carbide was Lord Kelvin, the famous English physicist, whose reply to Willson, stating that the substance received was calcium carbide, was dated October 3, 1892, two months before Moissan's first publication. Borchers's claims are too vague to waste space on. Willson's priority is now generally recognized excepting in France. The German Government has acknowledged it, and has annulled the German patent granted to Bullier.
Commercial carbide is essentially an American discovery, and it was developed industrially by Willson's associates before industrial action began abroad. Messrs. Dickerson and Suckert, of New York, were the first to undertake the industrial liquefaction of acetylene. Dr. G. de Chalmot, chemist, and Mr. J. M. Morehead, electrician, worked up the details of the furnace process in the early days at Spray, North Carolina, and the purity and the yield from a given weight of material of their carbide have never been excelled, though cheaper working furnaces are now in use.
Carbides of other metals can be made in the electric furnace, but, owing to the cheapness of the new material, calcium carbide is the only one of these which has industrial value as a source of acetylene. One pound of pure carbide yields 5.89 cubic feet of acetylene.
Thus far carbide has been found industrially valuable for two other purposes. The one is for carbonizing steel; experiments in Germany show that iron or soft steel takes up carbon more readily when it is heated with carbide than when it is heated with coal dust or charcoal. Some steel works are now using carbide for this purpose. The other use of carbide is more important. It is found to be a valuable germicide. It is said to be the most effectual preventive of black rot, and to destroy thePhylloxera, the two worst enemies of the grape. The action of the carbide as a germicide depends on its decomposition by the moisture of the soil, forming acetylene, which kills thePhylloxera. If the use of carbide on a large scale substantiates the claims made for it, this is a discovery of vast importance. The ravages caused by thePhylloxerain the vineyards of southern Europe, of Africa, and Australia must be ranked as great national calamities.
A temperature ranging from 2000° to 2500° C. (3600° to 4500° Fahrenheit) is required to make carbide. It is probable that this temperature can be economically attained only by the electric furnace using water power as the source of the electric current, and this is the only method used for making carbide, with the exception of theWalther process, which does not use electricity but depends on the intense heat generated by burning acetylene under pressure. In electric furnaces the formation of carbide depends simply on the heat of the arc, which fuses the mixture of lime and coke. The latest improvements on the first very simple forms of furnace have secured continuity of work and economy of electric energy. In the United States carbide is made exclusively in the Horry furnace. This furnace consists of a huge short cylinder or hollow wheel, mounted to revolve slowly on a horizontal shaft. The periphery of the cylinder is closed by removable cast-iron slats. As the cylinder is partly revolved on its axis from time to time, the slats are taken off from one side and replaced on the other, thus leaving the top always open. The cylinder is filled on one side with the powdered mixture of coke and lime. Into the mixture two vertical carbon electrodes project downward through the open top of the cylinder. As the carbide is formed, the cylinder is revolved, lowering the mass from the electrodes. The fused carbide cools, hardens, and is broken off and removed as it rises on the other side of the slowly revolving cylinder; new material is constantly fed in to maintain the level around the electrodes. The process in the Horry furnace is continuous; the furnace can be run without arresting the current until repairs are necessary. It is said to combine the different theoretical improvements referred to, and to reduce the cost of production. The Horry furnace is in use at Niagara Falls and at Sault Ste. Marie. At St. Catherine's, Canada, Willson is using his own furnace. Abroad, the older types of furnace, the Willson, Bullier, and Héroult, are those chiefly in use.
Horry Furnace, showing Electrodes.Horry Furnace, showing Electrodes.[5]
Horry Furnace, showing Gearing.Horry Furnace, showing Gearing.[5]
Horry Furnace, showing Carbide just removed.Horry Furnace, showing Carbide just removed.[5]
The actual ingot of good commercial carbide is nearly pure—ninety-six to ninety-nine per cent—but the ingot is surrounded by a crust of carbide mixed with unchanged material, containing forty toseventy per cent of carbide. Foreign makers break and blend ingot and crust to standard size, the best makers guaranteeing their carbide ninety per cent pure, giving five cubic feet of acetylene per pound (pure carbide gives 5.89 cubic feet). Eight to nine pounds of carbide per horse power in twenty-four hours, averaging five cubic feet of acetylene, is considered satisfactory work. The Union Carbide Company, which controls the sale of carbide in the United States, is selling graded carbides under guarantee, the first grade being the nearly pure ingot, the lower grade the crust.
As the moisture of the air decomposes the carbide, it must be broken up as soon as made, and packed in air-tight tin cans, varying in size from one to four hundred pounds.
The present price of carbide abroad averages $96.80 in large lots, and $7.26 per hundredweight in small lots, packing included; in the United States, $70 per ton in large lots, and $4.50 per hundredweight in small lots, packing included. In 1898, 4,650 tons are said to have been made in the United States and Canada, and a much larger amount abroad. The output for 1899 is estimated at 12,000 tons for the United States, with a capacity in the new works in erection at Sault Ste. Marie and at Niagara Falls of 41,000 tons. The new works building in Europe, to be finished in 1899-1900, have a capacity for making 80,000metric tons. These figures will justify the statement made at the beginning of this article, that the new industry has found ample capital.
The statement is still current that acetylene attacks copper and brass, forming an explosive compound. This is not true. Exhaustive experiments by Moissan and by Gerdes, keeping these and other metals in contact with acetylene for months at a time, have shown that the metals were not affected. The conditions under which the explosive copper acetylide is made in laboratories can not well occur in generators or gas holders. It has been said that acetylene is very poisonous; the experiments of many observers, and especially those of Gréhant, do not confirm this statement. Gréhant experimented on dogs, causing them to breathe mixtures of acetylene, air, and oxygen, which always contained 20.8 per cent of oxygen, this being the percentage of oxygen in pure air. By this device he was able to discriminate between the poisoning caused by acetylene and suffocation caused by insufficient oxygen. A mixture containing twenty per cent acetylene inhaled for thirty-five minutes did not seem to trouble the animal. A sample of the dog's arterial blood contained ten per cent of acetylene. A dog which inhaled a mixture containing forty per cent of acetylene died suddenly after fifty-one minutes, having inhaled one hundred and twelve litres of the mixture; the arterial blood contained twenty per cent acetylene. Gréhant proved that acetylene simply dissolves in the blood plasma, while carbon monoxide forms a compound with the hæmoglobin of the blood. A dog breathing a similar mixture of air, oxygen, and illuminating gas containing only one per cent of carbon monoxide quickly showed convulsive movements, and died after ten minutes; its blood contained twenty-four per cent of carbon monoxide. Thus acetylene, while slightly poisonous, is less poisonous than coal gas, and vastly less than water gas, which contains a high percentage of carbon monoxide.
A pressure of thirty-nine atmospheres and three quarters at 20° C. converts acetylene into a liquid weighing one third as much as the same volume of water, while one cubic foot of the liquid when released from pressure gives five hundred cubic feet of gas.
Hitherto acetylene is used only as a source of heat or as a source of light; yet with very cheap carbide it would prove useful in many ways in chemical industry, and its use would have the most wide-spread effect on industry and agriculture. For instance, a method of making alcohol from acetylene is patented abroad, and by another patented process it is proposed to make sugar from acetylene. With the present prices of alcohol, sugar, and carbide, these processes have no commercial value.
Acetylene may be made from the carbide in gas works anddelivered to the consumer through mains like ordinary illuminating gas; or it may be liquefied at a gas works and delivered to the consumer in the liquid form under pressure; or the consumer may purchase carbide and generate acetylene for his own consumption. All three of these methods are in use.
To understand the attitude of insurance companies and of consumers toward liquid acetylene it will be well to examine its record for the last few years. Those interested in methods for liquefying acetylene, and for reducing the pressure of the liquid at the place of consumption so that the consumer actually uses it as a gas under a water pressure of six inches or less, may find processes described in detail in the Progressive Age, and in other technical journals. Suffice it to say that the methods in use in this country and abroad are simple and effective. The purified acetylene is delivered in strong steel cylinders, which may be placed in a special building or case and need not be handled by the consumer. It has been proved by the exhaustive experiments of the eminent French chemist Berthelot that liquefied acetylene in cylinders can not be exploded by blows or shocks to the closed cylinder. If it is exploded, however, by causing a spark within the cylinder, the explosive force is very great, being about equal to that of gun cotton.
The use of the liquefied acetylene is so simple and clean that the attention of inventors was first turned to this mode of supply. It may in future come again into prominence despite the present strong feeling against it, its use in many cities being prohibited. This feeling was caused by a number of explosions, accompanied by loss of life. Three of these explosions occurred in factories for liquefying acetylene; one in a factory where liquid acetylene regulators were made; several in buildings of consumers. In October, 1896, Pictet's works in Paris were wrecked by the explosion of a cylinder filled with liquid acetylene; evidence proved that the cylinder was held in a vise, and that the two workmen killed were at the ends of a wrench, closing or opening the valve, supposing the cylinder to be empty. The explosion was caused either by a spark from friction in turning the screw, or by the too sudden opening of the valve and releasing the pressure, causing a shock sufficient to decompose the liquid. In December, 1896, the works of G. Isaac, in Berlin, were destroyed by an explosion in the condenser where the cooled acetylene was liquefied by pressure; Isaac and three workmen were killed. Evidence showed that through carelessness warm water instead of cold water was in contact with the condenser, thus warming the liquid and increasing the pressure to a point which burst the condenser. In December, 1897, the works of the Dickerson & Suckert Acetylene Gas Liquefying and Distributing Company in Jersey City were destroyedby fire caused by the explosion of a cylinder filled through carelessness of workmen with a mixture of air and liquid acetylene—i. e., with an explosive mixture—killing the superintendent and a workman. In the explosion at the regulator factory at New Haven, January, 1895, the valve of the cylinder, on which one of two workmen killed was working, broke; a large volume of acetylene escaped and ignited from a lighted candle. In all four cases the explosions were caused by ignorance or carelessness incident to the beginnings of a new industry, and could be avoided by experience and skill.
It should be stated that in the explosion at Paris all of the full acetylene cylinders were dug out of the ruins unhurt. The same was true at Berlin, where five full cylinders were blown against the wall of the building by the explosion of the condenser, but did not explode. At Jersey City sixty filled cylinders were exposed to the heat of the fire following the explosion; they were fitted with safety diaphragms of fusible metal; forty-eight remained intact, the acetylene burning off quietly as it escaped through the fused diaphragm, and twelve exploded, either on account of imperfection of the diaphragms or stoppage of the air passage leading from the diaphragm. The explosions of liquid acetylene in buildings of consumers have been due in every case to gross carelessness and ignorance on the part of the consumer.
Although one of the chief points in favor of the liquid acetylene is its portability, yet it can be shown that it is still easier to carry carbide to the consumer. One cubic metre of acetylene is compressed to two litres in liquid form; two litres of carbide weigh 4.44 kilogrammes, which will produce a cubic metre and a third of acetylene, reckoning three hundred litres to the kilogramme, which is the average guaranteed yield of carbide. The light tin carbide cans occupy less space and weigh less than the heavy steel cylinders, while the generation of the gas is simple and, with proper generators, perfectly safe. On the other hand, the generators must be cared for, must often be filled with fresh carbide, and from time to time must be cleaned. With the generator system acetylene is as safe as or safer than illuminating gas. Berthelot has shown that at pressures below two atmospheres a vessel filled with acetylene can not be exploded by the explosion of a cap of fulminating mercury within the vessel, nor by heating a wire which extends into the vessel to a white heat by an electric current. The reason is that the acetylene can not explode unless it is decomposed into its elements, carbon and hydrogen; to decompose it requires a certain amount of energy. While the energy of the glowing wire or of the exploding cap causes a local decomposition at the point of contact, it is not sufficient to spread the decomposition further. Acetylene forms an explosive mixture with air; so does illuminatinggas. The odor of acetylene is unpleasant; so is the odor of the water gas used generally in the United States, and the acetylene can be cheaply deodorized.
As the generator system, then, is the general one, the most important question to the consumer is what generator to buy, and it is a perplexing question. The carbide manufacture is so organized that it is everywhere under the control of powerful and responsible companies which sell a guaranteed product. The burners now in use are nearly all good. With generators it is different; the market is flooded with them at all prices, ranging in value from worse than useless to very good, as regards safety, economy, and quality of light. As the generator question is by far the most important and the least understood in the whole acetylene industry, it will be well to give a full account of the results of the experiments which have been made within the last two years on this question. The most exhaustive experiments are those of the English expert, Professor Lewes, and his results agree with those of other observers.
Lewes first determined the amount of heat developed by the decomposition of carbide by water, and the conditions which tend to lessen or increase the intensity of the reaction. The average result of the experiments as to the amount of heat was 446.6 calories for pure carbide, and a little less for commercial carbide (to state this differently, one pound of carbide, when decomposed by water, gives off heat enough to raise the temperature of 446.6 pounds of water 1° C., or to raise the temperature of one pound of water 446.6° C.). As the intensity of the heat developed determines the highest temperature attained during the decomposition, and is a function of the time needed to complete the action, and as the decomposition of carbide in contact with water is extremely rapid, it is evident that the temperature developed may be so high as to cause disaster. All the generators at present before the public may be classified under three heads: 1. Those in which water is allowed to drip or flow slowly on a mass of carbide, the evolution of the gas being regulated by the stopping of the water. 2. Those in which water in considerable volume is allowed to rise in contact with carbide, the evolution of the gas being regulated by the driving back of the water by the increase of pressure in the generating chamber. 3. Those in which the carbide is dropped or plunged into an excess of water.
The conclusions deduced from a large number of experiments were that when, as in type 1, water is allowed to drip or flow in a fine stream upon a mass of carbide, the temperature rapidly rises until after eighteen to twenty-five minutes the maximum is reached, which varies from 400° to 700° C. (720° to 1120° Fahrenheit), and it is probable that in some of the mass the higher limit is always reached,as traces of tar are usually found in the residual lime, in some cases in sufficient quantity to make the lime yellow and pasty, while vapors of benzene and other polymerization products pass off with the gas. Leaving the question of temperature in this type of generator, another important question is the length of time during which the generation of gas continues after the water supply is automatically cut off. It is found that gas is evolved with increasing slowness sometimes for an hour and three quarters after the water supply has ceased, the total volume of gas so evolved being large.
Type I.Type I.Type of Generator.[6]
The experiments showed that in any automatic generator of this type the cut-off should be so arranged that one quarter of the total capacity of the gas holder is still available to store the slowly generating gas.
The second class of generators bring about contact either by water rising from below to the carbide suspended in the cage (II,A), or by a cage of carbide suspended in a movable bell which, as it falls, dips the carbide into water, withdrawing the carbide from the water as the excessive generation of gas lifts the bell (II,B). Lewes found that under certain conditions generators of the type II,Bwere far worse than those of type I.
Type II, A. Type II, B. Type III.Type II,A.Type II,B.Type III.Types of Generators.[6]
The trials were made with a movable glass bell, with counterweights, containing a half-pound of carbide. The maximum temperatures reached in four trials were 703°, 734°, 754°, and 807° C. Excessive heating took place in every case; in the last mentioned the temperature was far above the point at which acetylene is decomposed into carbon and hydrogen, a thin black smoke being formed immediately around the carbide while tar vapor poured out. On removing the residue after cooling it was found to be coated with soot and loaded with tar. On several occasions the charge was removed from the generator just after the maximum temperature was reached, and was found to be at a bright red heat.
These experiments are of the greatest practical importance. At 600° acetylene begins to polymerize—i. e., to form more complex hydrocarbons, which are liquid, or solid, at ordinary temperatures. Probably in the generator acetylene is first given off so rapidly that the heat does not act on it, but as decomposition advances into thecenter of the mass of carbide, the acetylene generated has to pass through the external layers, which, as shown, may be at high temperatures, above that at which acetylene decomposes; thus a considerable amount of gas is lost, and the tar formed may distill into the generator and tubes, clogging the tubes. A more serious evil is the deterioration in the illuminating quality of the gas. Samples of the gas were taken as the maximum temperature was approached, and analyzed with this average result: Acetylene, seventy per cent; other hydrocarbons, eleven per cent; hydrogen, nineteen per cent. This reduces the illuminating value from two hundred and forty to one hundred and twenty-six candles. The hydrocarbons consist largely of benzene, which requires three times as much air for complete combustion as acetylene does. The best possible acetylene burner smokes when the acetylene contains benzene.
At first sight these experiments would seem absolutely to condemn generators of class II, yet the fact remains that some excellent generators are of this type. Under certain conditions excessive overheating may be avoided. The rising bell shown in II,Bshould be discarded. Generators in which the water rises from below, and slowly attacks the carbide, can be made safe if the water is never driven back from the carbide, and the carbide is in separated layers as in II,A. Under these conditions the water is always in excess at the point where it attacks the carbide, so that the evaporation, by rendering heat latent, keeps the temperature down, the temperatureof the melting point of tin, 228° C., being rarely reached in good generators where these conditions are met.
Undoubtedly the best generators, and the only ones which from a scientific point of view should be employed, are those of class III, in which carbide falls into an excess of water. In such generators it is impossible to get a temperature higher than the boiling point of water, 100° C., while with a properly arranged tank the temperature never exceeds that of the air by more than a few degrees. Under these conditions the absence of polymerization and the washing of the nascent and finely divided bubbles of gas by the limewater in the generator yield acetylene of a degree of purity unapproached by any other form of generator.
When acetylene is burned in air under such conditions that the flame does not smoke, it has been proved by Gréhant that there is no carbon monoxide among the combustion products; the acetylene combines with the oxygen of the air to form carbon dioxide and water (C2H2+ 5O = 2CO2+ H2O). One cubic foot of acetylene requires two and a half cubic feet of oxygen. Supposing a room to have an illumination equal to sixty-four standard candles; this amount of light from candles would use up 38.5 cubic feet of oxygen from the air, and would give off forty-three cubic feet of carbon dioxide; petroleum requires, in cubic feet, twenty-five of oxygen, and gives off forty of carbon dioxide; gas burned with a flat flame requires about twenty-five oxygen and gives nineteen carbon dioxide—with an Argand flame a little less, while with the Welsbach burner gas requires only three oxygen, and gives off 1.8 carbon dioxide; acetylene requires five oxygen and yields four carbon dioxide. So that, light for light, acetylene fouls the air less than any ordinary illuminant excepting the Welsbach gas burner. (With incandescent electric light there is no combustion and no fouling of the air.)
Under the best conditions five cubic feet of acetylene give a light of two hundred and forty candles for one hour, or we may speak of acetylene as a two-hundred-and-forty-candle gas. Yet this statement, though strictly true, may be misleading. When ordinary illuminating gas is tested with the photometer, it is burned from a standard flat-flame burner, burning five cubic feet per hour. Now the amount of light given by such a gas flame is no greater than is pleasant to the eye; it is true that if we burn five cubic feet of acetylene from a suitable flat-flame burner, a light of two hundred and forty candles is given, but it is unfair to take this ratio as representing the actual relative illuminating value of the two lights, because we neither need a light of two hundred and forty candles, nor is such an amount of light issuing from one burner endurable to the eye. One-foot or one-half foot acetylene burners are used for domestic lighting;light from the best one-foot burners averages thirty-two to thirty-five candles per cubic foot. With acetylene, as with every other illuminating gas, the smaller the burner and consumption, the less light per cubic foot of gas is obtained. Another important point is that while these figures represent the best practical illumination obtained from acetylene by the burners hitherto in use, the standard flat-flame burner does not give the best gaslight; with a good Welsbach burner a cubic foot of illuminating gas will give a seventeen-candle light as an average. The comparison, to be fair, should be between acetylene and the Welsbach light.
The reader will ask whether it is not possible to burn acetylene with other forms of burner, or to use it with Welsbach mantles. Successful acetylene burners of the Argand or of the regenerative type have not yet been introduced; but in Germany a new acetylene burner with Welsbach mantle promises good results. Experiments in England with an acetylene Bunsen burner and Welsbach mantle gave a light of ninety candles per cubic foot of acetylene used. It remains to be seen whether it is necessary to modify the composition of the mantles because of the intense heat of the acetylene Bunsen flame, which gives a temperature of 2100° to 2400° C. (3812° to 4397° Fahrenheit).
It would extend this article to undue length to speak of the various uses of acetylene as an enricher of other gases, but a mixture of acetylene and Pintsch oil gas now in use on all the Prussian state railways deserves mention, as it is a success, and ten thousand tons of carbide will be used this year for lighting cars by this system. Lewes's new invention of a very cheap methane water gas which is enriched by acetylene, carried to the consumer through mains, and burned in ordinary burners, is also promising.
Insurance and police regulations vary for every country. As a rule, restrictions are put on the use of liquid acetylene, and on the amount of carbide to be kept in storage. Generators must stand in separate buildings, which, in towns, must be fireproof.
The Willson patents cover the manufacture of crystalline carbide in the United States, Canada, and the South American states; and, as all carbide made by the electric furnace is crystalline, no carbide can be made independently of these patents in these countries.
In conclusion, it may be predicted that within the next few years acetylene will prove a factor in giving us an improved and cheaper light. Whether this will be an acetylene-Welsbach light or whether the acetylene will be chiefly used as an enricher of cheaper gases the future will show.
By WILLIAM KEITH BROOKS,
PROFESSOR OF ZOÖLOGY IN THE JOHNS HOPKINS UNIVERSITY.
You are aware that the pedagogue is no longer treated with that deference and respect which he feels to be due to his love of learning. Past is all his fame. Past is the day when the village all declared how much he knew. Nowadays he is accustomed to be told by the rustics, who once gazed and wondered, that he is old-fashioned and out of place in our modern world; that he does not represent the nation; that the love he bears to learning is at fault; and that the university the people want must be universal like an omnibus, with a place for all, either for a single square or to the end.
He is also used to hearing from those successful people of whom all must speak with reverence—those who have demonstrated their superiority by laying their hands on everything they think worth the getting—that he is a mere "bookish theorist," and that they are much more able to show him the path to success than he to tell them anything to their advantage.
Unless he can minister to their comfort or entertainment, or make smooth the royal road to learning, or at the very least help to maintain the patent office, he is told to be content with such treatment as they think good enough for him, and to keep himself to his work of teaching the lower classes to be lowly and reverent to all their betters.
I have been much interested of late by two books on certain aspects of modern society. One treats of the dangers which threaten liberal culture and constitutional government, and all the best products of civilization, through the increasing prevalence of the belief that our institutions have beendevisedby a few for their own selfish ends. So long as men differ in natural endowments the ignorant and the incapable and the unsuccessful must outnumber those whose industry and energy and foresight insure success. As those who have little have always outnumbered those who have much of the desired fruits of civilization, this writer says that one of the great questions of the day is whether, in last resort, the world shall be governed by its ignorance or by its intelligence. He is alarmed by the diffusion of belief that our established institutions do not represent the people, and that they are hostile to the best interest of mankind, and by the prevalence of the opinion that the true way to reform the world and to secure rational progress is to intrust the organization and administration of government and ofeducation and of all matters of public interest and importance to the majority.
The danger so clearly pointed out is real, beyond question; but I can not agree with the author that it is exclusively or distinctively modern. If some in our day interpret the belief that the voice of the people is the voice of God, as conviction that the loudest voice is most divine; if they assert that the man with pure and lofty ideals of education and duty and loyalty is a public enemy; we must remember that so wise a man as Aristotle taught, in the day of Athenian democracy, that the man who is virtuous in undue measure is a moral monster, as justly repugnant to his neighbors as one pre-eminent in vice.
If the first book calls Aristotle to mind, one must often think of Jeremiah while reading the second, for its author is a dismal prophet, who holds that, formidable as unbridled democracy seems, it is helpless in the struggle with organized plutocracy, and that its efforts to shake off the restraints and limitations of social existence can end in nothing but a more crushing despotism, while submission may bring such rewards of merit for good behavior in the past and such prizes for good conduct in the future as seem to the givers to be good investments.
Both writers draw many of their illustrations from the history of our own country, and they hold that our great political contests are struggles between those who wish to maintain our institutions for the sake of what they can themselves make out of them, and those who seek to wreck the ship of state for very similar reasons.
Some hold that, these things being true, they can show the learned professor how he may win back, through the struggle between these two great classes of mankind, some of that confidence in his wisdom which his predecessors enjoyed. They tell him he may make his learning represent the people if he will extend his university until it becomes as universal as the kindergarten, and that he may at the same time increase his popularity with the select if he will devote more of his time and more of his energy to that branch of learning which was in olden times pursued in that secluded cloister called the campus, although it is better known to the polite society of our day through the banjo club, the football team, and the mask and wig club.
If he will cultivate these two fields, and, refraining from the theoretical pursuit of empty generalities, will enter upon a three months' campaign of education at some time when men's minds are stimulated by the heat of faction to welcome calm discussion of the principles of common honesty and good citizenship, he can not fail to win the respect and confidence of all.
When I wrote this last sentence I thought that it was all out of my own head, and I was proud of it; but as I laid down my pen in my satisfaction for a moment's rest, my eye fell upon this passage in the prospectus of a new university—one which is said, in the prospectus, to be not only universal, but cosmopolitan: "When a question arises which divides scholars, like the tariff, the causes and course of the Reformation, money, etc., the student will be referred to the ablest exponents of the opposing sides."
No professor can plead ignorance of the way to enter this new career of usefulness. One can scarcely pick up a college catalogue or a magazine or a newspaper without learning how to make the university universal. One of the simplest plans, with which all are familiar, is to send to men with a reputation for learning a ruled form and a request that each will write, in the proper columns, the price, publisher, and title of the best book on his own subject—mathematics, astronomy, moral science, or whatever it may be—or, if he knows of no such book, that he will write one. An accompanying circular tells how these lists are to be scattered through the innumerable homes of our land, and how diplomas are to be distributed as prizes to those who, after purchasing the books, prepare and submit the most exhaustive permutations of their tables of contents.
Learned men who do not approve this plan are offered a choice from many others: six-week courses in law, medicine, and theology; summer schools for the promotion of science and the liberal arts; questions and answers in the educational column of some journal for the home; or a national university so universal that it shall supply lunches and learning for all out of the public chest, with no doorkeeper to examine passports.
The way to extend the university in this direction is so well understood that I will turn now to another part of our subject, for some may be less familiar with our opportunity to construct a royal road to learning for those who are entitled to use it.
A recent writer on education, who says American universities impose "upon young men in the nineteenth century a curriculum devised by dead-and-gone priests for the young men of the twelfth," calls upon the teachers of America to reconstruct their curriculum on psychological principles. I myself am no psychologist, and while I fail to see how this fact concerns the public, it has recently been pointed out in print, although no one has ever charged me with lack of reverence for the psychologist. In truth, he is to me what the good old family doctor is to many, for I am convinced that it would be hard to name one among all the educational ills that flesh is heir to that he would not be able to throw on the spot, with agood collar-and-elbow hold. I have a prodigious respect for those fine big wordscurriculumandpsychological principles, and I welcome the plan for reconstructing the curriculum on psychological principles the more eagerly because it is extremely simple and not hard to understand, like some psychological utterances. In fact, it is so very simple and easy that it is sure of enthusiastic indorsement by innumerable children, for this reformer's plan is neither more nor less than the abolition of the pedagogue.
"If," he says, "I was director general of education for all America" (which at the present moment he is not), "I would abolish colleges, but send American youths to travel for two years in Europe. In my opinion," he says, "a father who has sons and daughters of a proper age to go to college will do better by his children if he sends them for two years to travel in Europe than if he sends them for three years to an American or English university."
Admirable and simple as is this plan for ascending Parnassus in vestibuled trains of drawing-room cars, personally conducted by Grant Allen, this psychologist seems to me to err in thinking it new, for it was in high favor in England during the reign of that merry monarch who was always so furious at the sight of books that his queen, who loved reading, had to practice it in secret in her closet.
Euphranor having asked, in the reign of George II, "Who are these learned men that of late years have demolished the whole fabric which lawgivers, philosophers, and divines have been erecting for so many ages? Lysicles, hearing these words, smiled and said he believed Euphranor had figured to himself philosophers in square caps and long gowns; but, thanks to these happy times, the reign of pedantry was over. Our philosophers, said he, are of a different kind from those awkward students. They are the best-bred men of the age, men of the world, men of pleasure, men of fashion, and fine gentlemen. I will undertake a lad of fourteen bred in the modern way shall make a better figure and be more considered in any drawing-room or assembly of polite people than one at four-and-twenty who hath lain by a long time at school and college. He will say better things in a better manner, and be more liked by good judges. I say, when a man observes and considers all this, he will be apt to ascribe it to the force of truth and the merits of our cause, which, had it been supported by the revenues and establishments of the Church and universities, you may guess what a figure it would make by the figure it makes without them. People begin to open their eyes. It is not impossible but the revenues that in ignorant times were applied to a wrong use may hereafter, in a more enlightened age, be applied to a better."
"The money that went to found the Leland Stanford or theJohns Hopkins University," says the modern reformer, "would have been immeasurably better spent in bringing St. Marks at Venice and the Uffizi at Florence into the lives of innumerable young Americans. Here, then, is the opportunity for a wiser Cornell."
A few years ago an acquaintance of my own, himself an accomplished psychologist, brought with him to Washington a young man, a native of north Greenland, that he might take into his life the best substitute for St. Marks at Venice that this country affords. While limited in range, the results were as definite as one could wish, for two of the most refined delights of our wonderful civilization—rum and horses—were at once taken into the life of Eskimo Joe with all the fresh enthusiasm of youth. In his boyish impetuosity he could not see why a hired horse should not have the fleetness of Santa Claus's reindeer and the endurance of wild dogs; and as few horses survived the first lesson, the psychologist soon reconstructed the curriculum, for Joe's progress in rum and oysters was most gratifying. You who have attended my lectures in anthropology will remember that Nature has bestowed on the Eskimos two endowments which are not elsewhere found united, although they are exhibited separately in high perfection by the anaconda and the camel. Joe was able to load himself with food and drink like a pirate ship victualed for a long cruise, and he became so proficient in three months that a two-year course seemed unnecessary, so he was shipped off to Labrador at the first opportunity, and was left there to carry St. Marks at Venice into the homes of Greenland as best he might. It is clear that our psychological reformer's plan is not new, but he says our curriculum is some thousand years behind the times, and he asks, "Will somebody one day have the wisdom to perceive that the education which sufficed for the mediæval England of the Plantagenets is not absolutely adapted to the America of the nineteenth century?" I myself know so little of the curriculum of that day that this charge may, for all I know, be well founded, and if so it were a grievous fault. For all I know the dead-and-gone priests of the twelfth century may have read Homer in the original Greek, and carried on their studies in trigonometry and navigation with the aid of logarithms and the nautical almanac, although it has come in my way to know something of their method of teaching zoölogy, for my studies have led me to examine a text-book on this subject, which was written early in the twelfth century for the education of the young Queen Adelaide, who was married to Henry I of England in 1121. The dedication is as follows:
"Philippi de Thann into the French language has translated the Bestiary, a book of science, for the honor of a jewel, who is avery handsome woman, Aliz is she named, a queen is she crowned, Queen she is of England, may her soul never have trouble! In Hebrew in truth Aliz means praise of God. I will compose a book, may God be with the commencement!"
As a sample of the zoölogical curriculum of the twelfth century take this chapter:
"Onager by right is named the wild ass; of it the Physiologus says, in his speech, when March in his course has completed twenty-five days, then that day of the month he brays twelve times, and also in the night for this reason, that that season is the equinox, that is that night and day are of equal length; by the twelve times that it makes its braying and its crying, it shows that night and day have twelve hours in their circuit. The ass is grieved when he makes his cry, that the night and day have equal length; he likes better the length of the night than of the day. Now hear without doubt the signification of this. Onager signifies the devil in this life; and by March we understand all the time that we have; by the day we understand good people, by right, who will go in light; and by night we understand those who were Neros; and by hours we understand the number of people. And when the devil perceives that his people decrease, as do the hours which are in the night, after the vernal equinox which we have in March, then he begins to cry, to deplore greatly, as the ass does which brays and crys."
One need not go back to the middle ages for a measure of progress, for all who remember the American college of thirty years ago know there has been notable improvement in this short time, and they also know that every change has not been an improvement. All who are concerned with education see many defects, and wish to do what they can to remedy them, and to increase the efficiency and usefulness of our whole educational system in all its branches from the lowest to the highest, although I believe they still find much wisdom in the advice of the prophet of old, "that we make a stand upon the ancient way, and then look about us and discover what is the straight and right way, and so walk in it."
Many who are now before the public as reformers seem to me to fall into error through belief that our educational system has beendevisedby some one, either in the twelfth century or at some other time, and that they may therefore hope to devise a better. All who know that it is a highly complex and delicate organism which has grown up imperceptibly and naturally in accordance with many needs, fulfilling many different purposes and acting in many diversified and far-reaching ways, know also that while reform always has been and always will be needed, organic change is quite another matter. They know, too, that a disposition to pull it topieces in the interest of some theory or speculation must inevitably end in disaster, for they must agree with Bacon that "it were good, therefore, that men in their innovations would follow the example of time itself, which indeed innovateth greatly, but quietly, and by degrees scarce to be perceived."
The complaint that learning is no longer treated with due deference is not exclusively modern, for it was enumerated long ago among the things that are not new under the sun; and he who for his own pleasure or distinction devotes himself to work in fields that yield nothing but the interest of the exploration should look to his own pleasure for his reward, since learning is no more exalted by turning it into an aristocratic and exclusive pleasure ground than by making it a shop for profit. While no weak and foolish brother of the laboratory should be permitted to think that he belongs to a favored class or has any claims to support or respect except for service rendered, it is the duty of our graduates to teach the world, by the example of their lives, what the work of the university is.
Lyceum lectures and summer schools and systematic courses of reading are good things, and the common school and the home are the foundation of all education. Travel is a most valuable adjunct, but those who are to profit by it must first know what they go out to see, "for else shall young men go hooded and look abroad little."
No school or college can improve its work by calling itself a university, although the prevalence of belief that its work is the work of a university may bring harm incalculable; for that university is universal, in the best sense of the word, where students are inspired with enthusiasm for truth by the example of those whose minds are "as a mirror or glass capable of the image of the universal world, and joyful to receive the impression thereof as the eye joyeth to receive light."
What nobler task can our graduate undertake than to teach the world that while the benefits which learning confers are its only claim to consideration, these benefits will cease so soon as they are made an end or aim? All men prize the fruit; but who else is there to tell them that the tree will soon be barren if they visit it only at the harvest, that they must dig about it and nourish it and cherish the flowers and green leaves? What better service can he render than to point out that the gifts of learning are like health, which comes to him who does not seek it, but flies farther and farther from him who would lure it back by physic or indulgence?
The two authors I referred to at the beginning can not both be right, and both may be partly wrong, for it is possible that neither plutocracy nor a democratic majority makes a state. No universityneed humble itself to seek the favor of either plutocracy or democracy if its graduates can convince mankind, by their own lives, that its aim is not to gain deference or success or distinction or reward of any sort, but solely to propagate and diffuse among mankind "that enthusiasm for truth, that fanaticism of veracity, which is a greater possession than much learning, a nobler gift than the power of increasing knowledge."