CHAPTER VII.
Heat, the cause of many wonders—Its universal diffusion and application—Story of a burning-glass—The Augustine friars and the Jesuits—Impostures as to the endurance of heat—Burning mirrors—The blow-pipe—The Giants’ Causeway—Application of currents of heated air—Travelling by steam.
Heat, the cause of many wonders—Its universal diffusion and application—Story of a burning-glass—The Augustine friars and the Jesuits—Impostures as to the endurance of heat—Burning mirrors—The blow-pipe—The Giants’ Causeway—Application of currents of heated air—Travelling by steam.
Heatis everywhere present: every body that exists contains it in quantity to which we can assign no limits. The endless variety of forms which are spread over and beautify the surface of the globe, are to be traced to its influence. Without it, the land and the water would fall into one formless and impenetrable mass, and the air now essential to life, prove absolutely poisonous. We shall find in connexion with it, therefore, many extraordinary phenomena.
When Labat the Jesuit visited the Peruvians, he took the naked arm of one of them, and, concentrating on it the rays of the sun by means of a powerful lens, soon made him cry out with pain, while the others looked on with wonder, not unmixed with indignation. How could this effect be produced? was instantly the question; and, as promptly, the cause was declared to be infernal. In vain did Labat assert that it was merely natural. ThePeruvians made many attempts to obtain possession of the lens in order to destroy it, and deliver themselves from the power of that which they regarded as able to bring upon them the vengeance of the gods.
Much surprise has sometimes been awakened by an apparent insensibility to intense heat. An instance of this occurred when a rivalry existed between the Augustine friars and the Jesuits. The father-general of the Augustine friars was dining with the Jesuits; and, when the table was removed, he entered into a formal discourse of the superiority of the monastic order, and charged the Jesuits with assuming the title of “fratres,” while they held not the three vows which other monks were obliged to consider sacred and binding. The general of the Augustine friars was very eloquent and very authoritative—and the superior of the Jesuits was very unlearned.
The Jesuit avoided entering the lists of controversy with the Augustine friar, but arrested his triumph by asking him if he would see one of his friars, who pretended to be nothing more than a Jesuit, and one of the Augustine friars who religiously performed the three vows, show instantly which of them would be readier to obey his superior?
The Augustine friar consented. The Jesuit then turning to one of his brothers, the friar Mark, who was waiting upon them, said, “Brother Mark, our companions are cold; I command you, in virtue of the holy obedienceyou have sworn to me, to bring here, instantly, out of the kitchen-fire, and in your hands, some burning coals, that they may warm themselves over your hands.” Father Mark instantly obeyed; and, to the astonishment of the Augustine friar, brought in his hands a supply of red burning coals, and held them to whoever chose to warm himself; and, at the command of his superior, returned them to the kitchen hearth. The general of the Augustine friars, with the rest of his brotherhood, stood amazed; he looked wistfully on one of his monks, as if he wished to command him to do the like. But the Augustine monk, who perfectly understood him, and saw this was not a time to hesitate, observed, “Reverend father, forbear, and do not command me to tempt God: I am ready to fetch you fire in a chaffing-dish, but not in my bare hands.” The triumph of the Jesuits was complete, and it is not necessary to add, that “themiracle” was noised about, and that the Augustine friars could never account for it, notwithstanding their strict performance of the three vows! And yet here was no mystery. According to sir James Mackintosh, “In theMercure de France, there is a very curious account of experiments made at Naples to discover the means by which jugglers have appeared to be incombustible. They seem to be completely discovered, and chiefly to consist in, first, gradually habituating the skin, the mouth, throat, and stomach, to great degrees of heat; second, in rubbing the skin with hardsoap, and in covering the tongue with hard soap, and over that with a layer of powdered sugar. By these means, the professor at Naples is enabled to walk over burning coals, to take into his mouth boiling oil, and to wash his hands in melted lead. The miracles of several saints, the numerous escapes from the fiery ordeal, and tricks now played by the Hindoo jugglers, are thus perfectly explained; and all these prodigies may be performed in a fortnight by any apothecary’s apprentice.”
Other instances of endurance are merely pretended. In country places, a conjurer sometimes appears in the streets, professing that he is able to eat fire; and yet he only rolls together a ball of flax or hemp, lights it, rolls round it some more of the same material, slips it cunningly into his mouth, and breathes through it to revive the flame; and so long as he inspires the air through the nostrils, and not through the mouth, he suffers no injury. A performer, named Richardson, in the seventeenth century, pretended to pour melted lead upon his tongue; but it is probable that he used the fusible metal formed of bismuth, tin, and lead, which melts at a low temperature, and which the writer has seen fused on a card, and poured into the hand with impunity by a person accustomed to handle hot substances.
Not many years ago, a man named Chaubert professed to be incombustible; but it has been proved that the human body is capable of bearing a very high degree of heat. Men ofunquestionable integrity have surpassed all his wonders. Sir Charles Blagden exposed himself in a heated room where the heat was one or two degrees above 260°, and remained eight minutes in this situation. Eggs and a beef-steak were placed on a tin frame, near the thermometer, and in the space of twenty minutes the eggs were roasted quite hard, and in forty-seven minutes the steak was not only dressed, but almost dry. Another beef-steak, similarly placed, was rather over-done in thirty-three minutes. Chantrey, the celebrated sculptor, accompanied by five or six friends, also entered a furnace, and, after remaining two minutes, brought out a thermometer which stood at 320°. Some pain was experienced in this experiment, but it placed beyond all doubt that the human body has a remarkable power of enduring heat. Chaubert excited much wonder by taking phosphorus into his mouth; but, as that substance, when deprived of air, will not burn, he always closed his lips, and retired to eject the phosphorus immediately afterwards.
We turn now from the resistance of heat by chemical means, to some striking examples of its power.
The name of the Giants’ Causeway arose, probably, from an idea of the supernatural power, entertained in times of ignorance and superstition. And yet it is demonstrated that vast masses of rock are to be traced to causes strictly natural. Basalt is of very frequentoccurrence on the surface of the globe, and is frequently detected in a variety of volcanoes, both extinct and active. The greatest mass of basalt hitherto observed is that in the Deccan, which constitutes the surface of many thousand square miles of that part of India. In other instances, it occurs in horizontal tabular masses, and is columnar. Sometimes, the basaltic columns are curved, and of this there is a beautiful example in the island of Staffa. Now basalt is not a crystalline substance, for as it is not capable, as all crystals are, of cleavage in the line of its planes, or at some angle with them, it is concretional. Its structure resembles an onion, or any bulbous root, for, in the centre, is a solid mass, about which are others just like the parts of the vegetable products already mentioned. These portions of basalt are at first of an oval form, and then they gradually become rudely hexagonal. Some non-columnar basalts show no trace of any particular arrangement of parts, while others have a globular structure, so that when the rock becomes much decomposed, it has the appearance of numerous bomb-shells and cannon-balls cemented together.
Here, then, we have an extraordinary effect of heat. Mr. Gregory Watt took seven hundred weight of the substance named rowley rag, kept it in fusion more than six hours, and cooled it so gradually, that eight days elapsed before it was taken from the furnace. The shape of the mass was uneven and while thethinner portion was, in consequence of more rapid cooling, vitreous, the thicker was stony; the one state passing into the other. Numerous spheroids were also formed, some being two inches in diameter. They were radiated with distinct fibres, the latter also forming concentric coats, when circumstances were favourable to such an arrangement. When the temperature had been sufficiently continued, the centres of the spheroids became compacted before they had attained the diameter of half-an-inch. When two spheroids came into contact, no penetration ensued; but the two bodies became mutually compressed and separated by a plane, well defined, and invested with a rusty colour. When several met, they formed prisms. In reasoning on these facts, Mr. G. Watt observes: “In a stratum composed of an indefinite number in superficial extent, but only one in height, of impenetrable spheroids, if their peripheries should come in contact in the same plane, it seems obvious that their mutual action would form them into hexagons; and if these were resisted below, and there was no opposing cause above them, it seems equally clear that they would extend their dimensions upwards, and thus form hexagonal prisms, whose length might be indefinitely greater than their diameters.”
That the great power in operation in the formation of basaltic columns is heat, appears to be indisputable. There is, for example, a bed of sandstone in furnaces for smeltingmetals, and, in the course of time, it requires to be repaired. Portions, taken out, on such occasions, have been found to have a columnar appearance: the heat of the furnace having changed the form of the substance, not by any fusion of its parts, but by a peculiar arrangement of them, thus giving them the specified figure.
Another astonishing result of this natural power is seen in the eruption of a volcano. The eye of a traveller, perhaps, as it is turned towards Vesuvius, discerns a dark red spot on the mountain’s side, issuing from an orifice near to the crater. But soon, that deep burning light apparently spreads out, or flows on into a long wide stream, descends the entire length of the great cone, and reaches to the plain below. But, as the first light was seen through and behind the mists which follow the departure of the sun, so now its extended influence is only rendered visible by the increasing gloom. But, as the eye is still attracted towards this remarkable eminence, a pillar of fire is seen rising up from the crater high into the air; while innumerable lights appear, like so many natural fire-works rushing upwards, and falling in a glowing shower, on the outer sides of the crater, which soon present the aspect of a heap of fire. Large and red-hot stones are flung forth from time to time, from the same troubled source, to fall, roll down the sides of the crater, and lose their brightness.
Mountains that are liable to volcanic action,before an eruption takes place, are generally the most fertile, and the most attractive of all eminences. Illustrations of this remark are found upon a magnificent scale in Mexico; and, among the rest, that of Jorullo, in the extensive intendency of Valladolid, lying on the west coast of America, between the intendencies of Mexico and Guadalaxara, (pronounced Quadalahàra.) Mechoacan, a part of it, is an expanse of table-land which enjoys a fine and temperate climate, and is intersected with hills and charming valleys, presenting an appearance unusual in the torrid zone, of extensive and well-watered meadows. On the twenty-ninth of September, 1759, from the centre of a thousand burning cones was thrown up the volcano of Jorullo; a mountain of scoriæ and ashes, seventeen hundred feet high, in an extensive plain, and covered with most luxuriant vegetation. When plains, hills, and valleys, are thus spoken of, the reader should remember, that all of them are reared upon the lofty chain of the Andes, for volcanic eruptions only, so far as we know, take place in mountainous regions.
But some of the most remarkable examples are to be met with in the Spice Islands, or Moluccas. The pointed and conical mountains, which characterize this group of islands, exhibit great fertility. Nothing can surpass the richness of vegetation with which their sides are covered, nor the balmy healthfulness of the breezes that encircle round them, to temper the heats of the sultry zone. But the nature ofthese mountains is closely connected with volcanic action; so that, in fearful apprehension, we might look at each one of these beautiful peaks, as if it were destined one day to be torn from its station and thrown into the sea.
“I will stretch out mine hand upon thee, and roll thee down from the rocks, and will make thee a burnt mountain,” was one of the Divine denunciations against Babylon, Jer. li. 25. Judgment has not thus fallen on Ternate, one of the most lovely of the cluster just adverted to; but the top of the highest rock has been torn off, and hurled from a height of five or six thousand feet, into the sea. A huge gap was left behind, which seemed to a traveller when standing on the edge, like a deep valley, or ravine, betwixt two mountains. As the portion rent away in this tremendous struggle was split into fragments of various sizes, there is, besides, a vast pile at the water’s edge, a road, or causeway, strewed with half-vitrified pieces of rock and cinders, from the margin of the rift to the declivity of the mountain; so that the island, so lovely under other aspects, presents on this side a fearful scene of desolation. What a striking comment on the words, “I will make thee a burnt mountain;”—I will tear off thy summit, shiver it into ten thousand pieces, and therewith overwhelm and destroy the natural verdure of thy sides, which once looked so goodly and so fair! Some time in March, 1839, another eruption took place at Ternate; so that, long before these ejectedmatters could yield to the decomposing action of the atmosphere, and afford a soil for vegetable growth, another layer, of equally forlorn and broken kind, was scattered over them.
In connexion with these astounding phenomena, it may be remarked that an apparatus has recently been contrived called the fire-annihilator, the origin of which is not a little curious. It is said that the inventor observed that the smoke hovering over a burning mountain diminished its fury, and that, on analysing it and combining similar elements, he discovered the means of extinguishing fires, and thus of arresting at the outset what might otherwise prove a tremendous calamity.
Many processes of art, like the operations of nature, are dependent on heat. By this agent, the most obdurate masses soften like wax, and yield to the forms which are demanded by our wants and our tastes; and compounds, knit together by stubborn affinities, are resolved by it into their original elements. The baron Von Tchivanhausen constructed a burning mirror in 1687, five feet three inches in breadth, and reflecting the solar rays with extraordinary power. When exposed to its force, wood took fire, and continued to burn, notwithstanding a most violent wind; and water, contained in an earthen vessel, quickly boiled, so that eggs were cooked, and the liquid soon after evaporated. Copper and silver were fused in a few minutes, and slate was transformed into a kind of black glass, which, when held by a pair ofpincers, could be drawn out into filaments. This mirror afterwards came into the possession of the king of France, and was kept in the Jardins du Roi. Other mirrors have been formed of different substances. At the Polytechnic Institution, some years ago, there were two metallic discs placed at the extreme ends of the great hall, and when a vessel of burning coals was held in the focus of one, and a piece of meat in the focus of the other, the latter was cooked with marvellous rapidity by a simple and apparently an unimportant instrument.
The blow-pipe has immense power. Two volumes of hydrogen, and one of oxygen gas, when pure, form a mixture which produces in this instrument intense heat, and most substances may be fused by the flame. In the experiments of Dr. E. Clarke, lime, strontion, and alumine, yielded to its powers. The alkalis were fused and volatilized almost the instant they came into contact with the flame: and rock crystal became a transparent glass full of bubbles. Opal changed into a pearly white enamel, and flint into one that was frothy. Blue sapphire was melted; and Peruvian enamel changed into a transparent and colourless glass. Lapis lazuli fused into transparent glass, with a slight tinge of green. Iceland spar, next in difficulty, as to fusion, to its native magnesia, melted at last into a limpid glass, giving out an amethyst-coloured flame. Diamond first became opaque, and was then gradually volatilized. Gold, mixed with borax as a flux, was fused; platinawire melted the instant it was brought into contact with the flame, and ran down in drops; brass wire burned with a green flame; and iron wire with brilliant sparks.
At a recent meeting of the British Association, Dr. Faraday exhibited some diamonds, which he had received from M. Dumas, which had, by the action of intense heat, been converted into coke. In one case, the heat of the flame of oxide of carbon and oxygen had been used; in another, the oxyhydrogen flame; and, in the third, the galvanic arc of flame from a Bunsen battery of one hundred pairs. In the last case, the diamond was perfectly converted into a piece of coke; and, in the others, the fusion and carbonaceous formation were evident. Specimens in which the character of graphite was taken by the diamond were also shown. The electrical characters of these diamonds were stated also to have been changed, the diamond being an insulator, while coke is a conductor.
A rope, nearly three miles long, was recently lying on the verge of the borough of Gateshead, which was shortly before a stone in the bowels of the earth. Smelted, the stone yielded iron. The iron was converted into wire. The wire was brought to the wire-rope manufactory of Messrs. R. S. Newall and Co., at the Teams, near Gateshead, and there twisted into a line 4,660 yards long. It was supposed to be the stoutest rope of the kind that was ever made. It weighs twenty tons, five hundredweights, andcost the purchasers upwards of £1,134. It was intended for the incline on the Edinburgh and Glasgow Railway, near the latter city. A rope of hemp of equal strength would weigh thirty-three tons and-a-half, and cost about three hundred pounds more. It would also entail greater expense while in operation, (owing to its greater weight,) and would sooner wear out.
“The process,” says thePharmaceutical Journal, “for purifying and agglomerating caoutchouc, preparatory to its being cut into sheets, and also for effecting the latter operation, are due to the ingenuity of M. Sievier. The general principle is this:—Pieces of caoutchouc, mixed, as they are in their native state, with various impurities, are put into a strong metallic drum, through which passes an axle, studded with chisel-shaped teeth. The interior of the drum is supplied with similar ones, but stationary. Therefore, when the axle is made to revolve, the caoutchouc becomes subjected to a most powerful rending and kneading motion, in the course of which sufficient heat is evolved, notwithstanding a current of cold water continually passes through the drum, to agglutinate the material into a compact mass. This mass is now subjected to the pressure of a powerful screw apparatus, and made to assume the form of a cuboid, from which sheets of caoutchouc may be eventually cut by the rapid vibratory action of a knife, kept moistened with water. As solvents forcaoutchouc, equal parts of coal naptha and turpentine are commonly used; and, of late, the bisulphuret of carbon has been much employed.”
Mr. J. Wishaw has lately shown the advantages arising from the application of currents of heated air to the following purposes: seasoning timber, generally; preserving timber, purifying feathers, blankets, clothing, etc.; drying coffee, roasting coffee, japanning leather for table-covers, and other purposes; drying silks, drying yarn, drying distillers’ tuns, drying papier-máché, and drying vulcanized india-rubber. The process has also been successfully tested for drying loaf-sugar, drying printing-paper, or setting the ink, to enable books to be bound more quickly than usual; drying starch, and converting it into dextine, or British gum; and preserving meat. It has been also stated, that sixty suits of clothes, which had belonged to persons who had died of the plague in Syria, had been subject to the process of purification, at a temperature of about 240°, and afterwards worn by sixty persons; not one of whom ever gave the slightest symptom of being affected by the malady. In describing these processes, the writer referred to the mode adopted by the North American Indians for preserving the meat of the buffalo—that of drying it in the sun; and stated that heated currents had been applied successfully. The discovery seems highly important for shipping; as, instead of sailorsconsuming salted provisions from one month’s end to another, they might thus have an occasional supply of fresh meat. Meat treated in this way occupies much less space, too, and is much lighter in weight. It is believed that the juices of the meat contain about seven-eighths of watery moisture: this, the current of heated air removes, leaving the albumen and all the flavour and nutrition behind.
That in the production of steam heat is of incalculable value, there needs no proof. We derive special advantage from it, in the results of that machinery which astonish us by their magnitude, as well as by their elegance. Steam wafts us, in a few hours, from one extremity of the land to the other, and renders America, once called the New World, accessible in a few days.
Another instance of its application, often overlooked, is thus stated in theQuarterly Review:—“That extraordinary line of steam communication between England and her eastern possessions, (somewhat oddly called theoverlandjourney,) of which Australia and New Zealand will hereafter form the extreme branches. The creation of the last twelve years, this communication has already acquired a sort of maturity of speed and exactness, notwithstanding the enormous distances traversed, and the changes necessary in transit from sea to sea. The Anglo-Indian mail in its two sections, and including passengers and correspondence, possesses a sort of individuality asthe greatest and most singular line of intercourse on the globe. Two of the first nations of Europe, France and Austria, struggle for the privilege of carrying this mail across their territories. Traversing the length of the Mediterranean, it is received on the waters of the ancient Nile—Cairo and the Pyramids are passed in its onward course—the desert is traversed with a speed which mocks the old cavalcades of camels and loitering Arabs—it is re-embarked on the Red Sea, near a spot sacred in scriptural history—the promontory projecting from the heights of Mount Sinai, the shores of Mecca and Medina are passed in its rapid course down this great gulf—it emerges through the straits of Babelmandel into the Indian seas—to be distributed thence by different lines to all the great centres of Indian government and commerce, as well as to our more remote dependencies in the straits of Malacca and the Chinese seas. There is a certain majesty in the simple outline of a route like this, traversing the most ancient seats of empire, and what we are taught to regard as among the earliest abodes of man—and now ministering to the connexion of England with that great sovereignty she has conquered, or created, in the east; more wonderful, with one exception, than any of the empires of antiquity; and, perchance, also, more important to the general destinies of mankind.”