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 is 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. The Peruvians 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
obedience you 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 “the _miracle_” 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 the _Mercure 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 hard soap, 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 of unquestionable 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 frequent occurrence
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 the thinner 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 smelting metals, 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 of
these 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 ejected matters 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
of pincers, 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;
platina wire 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, and cost 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 the _Pharmaceutical 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 for caoutchouc, 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 sailors
consuming 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 the _Quarterly Review_:--“That extraordinary line of steam
communication between England and her eastern possessions, (somewhat
oddly called the _overland_ journey,) 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 as the 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.”