Science, whose aim and end is to prove the harmony and “eternal fitness
of things,” also proves that we live in a world of paradoxes; and that
existence itself, is a whirl of contradictions. Light and darkness,
truth and falsehood, virtue and vice, the negative and positive poles of
galvanic or magnetic mysteries, are evidences of all-pervading
antitheses, which acting like the good and evil genii of Persian
Mythology, neutralise each other’s powers when they come into collision.
It is the office of science to solve these mysteries. The appropriate
symbol of the lecture-room is a Sphinx; for a scientific lecturer is but
a better sort of unraveller of riddles.
Who would suppose, for instance, that water—which everybody knows,
extinguishes fire—may, under certain circumstances, add fuel to flame,
so that the “coming man” who is to “set the Thames on fire,” may not be
far off. If we take some mystical grey-looking globules of potassium
(which is the metallic basis of common pearl-ash) and lay them upon
water, the water will instantly appear to ignite. The globules will swim
about in flames, reminding us of the “death-fires” described by the
Ancient Mariner, burning “like witches’ oil” on the surface of the
stagnant sea. Sometimes even, without any chemical ingredient being
added, Fire will appear to spring spontaneously from water; which is not
a simple element, as Thales imagined, when he speculated upon the origin
of the Creation, but two invisible gases—oxygen and hydrogen, chemically
combined. During the electrical changes of the atmosphere in a
thunder-storm, these gases frequently combine with explosive violence,
and it is this combination which takes place when “the big rain comes
dancing to the earth.” These fire-and-water phenomena are thus accounted
for; certain substances have peculiar affinities or attractions for one
another; the potassium has so inordinate a desire for oxygen, that the
moment it touches, it decomposes the water, abstracts all the oxygen,
and sets free the hydrogen or inflammable gas. The potassium, when
combined with the oxygen, forms that corrosive substance known as
caustic potash, and the heat disengaged during this process, ignites the
hydrogen. Here the mystery ends; and the contradictions are
solved;—Oxygen and hydrogen when combined, become water; when separated
the hydrogen gas burns with a pale lambent flame. Many of Nature’s most
delicate deceptions are accounted for by a knowledge of these laws.
Your analytical chemist sadly annihilates, with his scientific
machinations, all poetry. He bottles up at pleasure the Nine Muses, and
proves them—as the fisherman in the Arabian Nights did the Afrite—to be
all smoke. Even the Will o’ the Wisp cannot flit across its own morass
without being pursued, overtaken, and burnt out by this scientific
detective policeman. He claps an extinguisher upon Jack o’ Lanthorn
thus:—He says that a certain combination of phosphorus and hydrogen,
which rises from watery marshes, produces a gas called phosphuretted
hydrogen, which ignites spontaneously the moment it bubbles up to the
surface of the water and meets with atmospheric air. Here again, the
Ithuriel wand of science dispels all delusion, pointing out to us, that
in such places animal and vegetable substances are undergoing constant
decomposition; and as phosphorus exists under a variety of forms in
these bodies, as phosphate of lime, phosphate of soda, phosphate of
magnesia, &c., and as furthermore the decomposition of water itself is
the initiatory process in these changes, so we find that phosphorus and
hydrogen are supplied from these sources; and we may therefore easily
conceive the consequent formation of phosphuretted hydrogen. This gas
rises in a thin stream from its watery bed, and the moment it comes in
contact with the oxygen of the atmosphere, it bursts into a flame so
buoyant, that it flickers with every breath of air, and realises the
description of Goëthe’s Mephistopheles, that the course of
Jack-o’-lantern is generally “zig-zag.”
Who would suppose that absolute darkness may be derived from two rays of
light! Yet such is the fact. If two rays proceed from two luminous
points very close to each other, and are so directed as to cross at a
given point on a sheet of white paper in a dark room, their united light
will be twice as bright as either ray singly would produce. But if the
difference in the distance of the two points be diminished only one
half, the one light will extinguish the other, and produce absolute
darkness. The same curious result may be produced by viewing the flame
of a candle through two very fine slits near to each other in a card.
So, likewise, strange as it may appear, if two musical strings be so
made to vibrate, in a certain succession of degrees, as for the one to
gain half a vibration on the other, the two resulting sounds will
antagonise each other and produce an interval of perfect silence. How
are these mysteries to be explained? The Delphic Oracle of science must
again be consulted, and among the high priests who officiate at the
shrine, no one possesses more recondite knowledge, or can recal it more
instructively, than Sir David Brewster. “The explanation which
philosophers have given,” he observes, “of these remarkable phenomena,
is very satisfactory, and may easily be understood. When a wave is made
on the surface of a still pool of water by plunging a stone into it, the
wave advances along the surface, while the water itself is never carried
forward, but merely rises into a height and falls into a hollow, each
portion of the surface experiencing an elevation and a depression in its
turn. If we suppose two waves equal and similar, to be produced by two
separate stones, and if they reach the same spot at the same time, that
is, if the two elevations should exactly coincide, they would unite
their effects, and produce a wave twice the size of either; but if the
one wave should be put so far before the other, that the hollow of the
one coincided with the elevation of the other, and the elevation of the
one with the hollow of the other, the two waves would obliterate or
destroy one another; the elevation as it were of the one filling up half
the hollow of the other, and the hollow of the one taking away half the
elevation of the other, so as to reduce the surface to a level. These
effects may be exhibited by throwing two equal stones into a pool of
water; and also may be observed in the Port of Batsha, where the two
waves arriving by channels of different lengths actually obliterate each
other. Now, as light is supposed to be produced by waves or undulations
of an ethereal medium filling all nature, and occupying the pores of the
transparent bodies; and as sound is produced by undulations or waves in
the air: so the successive production of light and darkness by two
bright lights, and the production of sound and silence by two loud
sounds, may be explained in the very same manner as we have explained
the increase and obliteration of waves formed on the surface of water.”
The apparent contradictions in chemistry are, indeed, best exhibited in
the lecture-room, where they may be rendered visible and tangible, and
brought home to the general comprehension. The Professor of Analytical
Chemistry, J. H. Pepper, who demonstrates these things in the Royal
Polytechnic Institution, is an expert manipulator in such mysteries;
and, taking a leaf out of his own magic-book, we shall conjure him up
before us, standing behind his own laboratory, surrounded with all the
implements of his art. At our recent visit to this exhibition we
witnessed him perform, with much address, the following experiments:—He
placed before us a pair of tall glass vessels, each filled, apparently,
with water;—he then took two hen’s eggs, one of these he dropped into
one of the glass vessels, and, as might have been expected, it
immediately sank to the bottom. He then took the other egg, and dropped
it into the other vessel of water, but, instead of sinking as the other
had done, it descended only half way, and there remained suspended in
the midst of the transparent fluid. This, indeed, looked like magic—one
of Houdin’s sleight-of-hand performances—for what could interrupt its
progress? The water surrounding it appeared as pure below as around and
above the egg, yet there it still hung like Mahomet’s coffin, between
heaven and earth, contrary to all the well established laws of gravity.
The problem, however, was easily solved. Our modern Cagliostro had
dissolved in one half of the water in this vessel as much common salt as
it would take up, whereby the density of the fluid was so much augmented
that it opposed a resistance to the descent of the egg after it had
passed through the unadulterated water, which he had carefully poured
upon the briny solution, the transparency of which, remaining
unimpaired, did not for a moment suggest the suspicion of any such
impregnation. The good housewife, upon the same principle, uses an egg
to test the strength of her brine for pickling.
Every one has heard of the power which bleaching gas (chlorine)
possesses in taking away colour, so that a red rose held over its fumes
will become white. The lecturer, referring to this fact, exhibited two
pieces of paper; upon one was inscribed, in large letters, the word
“PROTEUS;” upon the other no writing was visible; although he assured us
the same word was there inscribed. He now dipped both pieces of paper in
a solution of bleaching-powder, when the word “Proteus” disappeared from
the paper upon which it was before visible; whilst the same word
instantly came out, sharp and distinct, upon the paper which was
previously a blank. Here there appeared another contradiction: the
chlorine in the one case obliterating, and in the other reviving the
written word; and how was this mystery explained? Easily enough! Our
ingenious philosopher, it seems, had used indigo in penning the one word
which had disappeared; and had inscribed the other with a solution of a
chemical substance, iodide of potassium and starch; and the action which
took place was simply this: the chlorine of the bleaching solution set
free the iodine from the potassium, which immediately combined with the
starch, and gave colour to the letters which were before invisible.
Again—a sheet of white paper was exhibited, which displayed a broad and
brilliant stripe of scarlet—(produced by a compound called the
bin-iodide of mercury)—when exposed to a slight heat the colour changed
immediately to a bright yellow, and, when this yellow stripe was crushed
by smartly rubbing the paper, the scarlet colour was restored, with all
its former brilliancy. This change of colour was effected entirely by
the alteration which the heat, in the one case, and the friction, in the
other, produced in the particles which reflected these different
colours;—and, upon the same principle, we may understand the change of
the colour in the lobster-shell, which burns from black to red in
boiling; because the action of the heat produces a new arrangement in
the particles which compose the shell.
With the assistance of water and fire, which have befriended the
magicians of every age, contradictions of a more marvellous character
may be exhibited, and even the secret art revealed of handling red hot
metals, and passing through the fiery ordeal. If we take a platinum
ladle, and hold it over a furnace until it becomes of a bright red heat,
and then project cold water into its bowl, we shall find that the water
will remain quiescent and give no sign of ebullition—not so much as a
single “fizz;” but, the moment the ladle begins to cool, it will boil up
and quickly evaporate. So also, if a mass of metal, heated to whiteness,
be plunged in a vessel of cold water, the surrounding fluid will remain
tranquil so long as the glowing white heat continues; but, the moment
the temperature falls, the water will boil briskly. Again—if water be
poured upon an iron sieve, the wires of which are made red hot, it will
not run through; but, on the sieve cooling, it will run through rapidly.
These contradictory effects are easily accounted for. The repelling
power of intense heat keeps the water from immediate contact with the
heated metal, and the particles of the water, collectively, retain their
globular form; but, when the vessel cools, the repulsive power
diminishes, and the water coming into closer contact with the heated
surface its particles can no longer retain their globular form, and
eventually expand into a state of vapour. This globular condition of the
particles of water will account for many very important phenomena;
perhaps it is best exhibited in the dew-drop, and so long as these
globules retain their form, water will retain its fluid properties. An
agglomeration of these globules will carry with them, under certain
circumstances, so much force that it is hardly a contradiction to call
water itself a solid. The water-hammer, as it is termed, illustrates
this apparent contradiction. If we introduce a certain quantity of water
into a long glass tube, when it is shaken, we shall hear the ordinary
splashing noise as in a bottle; but, if we exhaust the air, and again
shake the tube, we shall hear a loud ringing sound, as if the bottom of
the tube were struck by some hard substance—like metal or wood—which may
fearfully remind us of the blows which a ship’s side will receive from
the waves during a storm at sea, which will often carry away her
bulwarks.
It is now time to turn to something stronger than water for more
instances of chemical contradictions. The chemical action of certain
poisons (the most powerful of all agents,) upon the human frame, has
plunged the faculty into a maze of paradoxes; indeed there is actually a
system of medicine, advancing in reputation, which is founded on the
principle of contraries. The famous Doctor Hahnemann, who was born at
Massieu in Saxony, was the founder of it, and, strange to say, medical
men, who are notorious for entertaining contrary opinions, have not yet
agreed among themselves whether he was a very great quack or a very
great philosopher. Be this as it may, the founder of this system, which
is called HOMŒOPATHY, when translating an article upon bark in Dr.
Cullen’s Materia Medica, took some of this medicine, which had for many
years been justly celebrated for the cure of ague. He had not long taken
it, when he found himself attacked with agueish symptoms, and a light
now dawned upon his mind, and led him to the inference that medicines
which give rise to the symptoms of a disease, are those which will
specifically cure it, and however curious it may appear, several
illustrations in confirmation of this principle were speedily found. If
a limb be frost-bitten, we are directed to rub it with snow; if the
constitution of a man be impaired by the abuse of spirituous liquors,
and he be reduced to that miserable state of enervation when the limbs
tremble and totter, and the mind itself sinks into a state of low
muttering delirium, the physician to cure him must go again to the
bottle and administer stimulants and opiates.
It was an old Hippocratic aphorism that two diseases cannot co-exist in
the same body; wherefore, gout has actually been cured by the afflicted
person going into a fenny country and catching the ague. The fatality of
consumption is also said to be retarded by a common catarrh; and upon
this very principle depends the truth of the old saying, that ricketty
doors hang long on rusty hinges. In other words, the strength of the
constitution being impaired by one disease has less power to support the
morbid action of another.
We thus live in a world of apparent contradictions; they abound in every
department of science, and beset us even in the sanctuary of domestic
life. The progress of discovery has reconciled and explained the nature
of some of them; but many baffle our ingenuity, and still remain
involved in mystery. This much, however, is certain, that the most
opposed and conflicting elements so combine together as to produce
results, which are strictly in unison with the order and harmony of the
universe.