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