The daily dispatch. [volume] (Richmond [Va.]) 1850-1884, 1872-11-25

THE CONTRADICTIONS OF sC1ESCE.-Pro-
fessor Pepper, of London, recently made
his first appearance In public in the United
States before the Polytechnic Section Of the
American Institute. The Contradictions
of Sccnce' formed the subject OF pleasant
lecture, which tue Professor illustrated by
few well-chosen though simple experiments.
Some of the contradictions explained
were the sinking Of an egg In pure water
and its floating in brine the bleaching ac-
ton of chloride Of lime on a solution OF
indigo, causing letters written in the latter
to disappear, while it rendered visible some
characters painted in colorless mix
ture of iodide Of potassium aud starch
the boiling Of water by certain chem
icals and its freezing by others; the re-
action Of a solution of iodide Of potassium
on II solution Of corrosive sublimate, both
clear liquids, which, when combined in GER
tain proportions, throw down q scarlet pre-
cpitate of biniodidc Of mercury, which is
caused to disappear and the mixture again
made limpid by the addition OF I'm excess Of
the lodide of potassium, and the well-known
conjuring trick Of the magic bottle, which is
filled with weak sulphuric acid and water.
The mixture being poured into wine-glasses
previously rinsed out with solutions of salts
Of iron, lead, etc., changes its color SO as to
resemble different wines, milk, ink, etc.
In connection with the corrosive subli-
mate experiment the Professor animadvelted
quite strongly on the insecurity of modern
chemical testimony in courts of law. He
spoke of the extreme care and accuracy re-
qlired in the tests on which q mans life
might depend, and instanced how chemist
might be led, in applying the iodide of potas-
SUM test for the deadly corrosive sublimate,
to declare that the latter was not present in
his analysis, by simply adding drop of the
reagent in excess. The testimony of neither
one nor of two men, however expert, should
be regarded as convincing. A public officer
should be appointed whose duty it should
be to select three Well.known chemists, and
require each to make separate analyses.
This done, they should meet and prepare
Judges report, which should be received in
evidence, and the experts themselves should
be subjected to severe examination and cross
examination apart from each other. Such
testimony should be in favor of neither side
of the case, but simple, calm exposition
Of the truth.
The Professor gave quite an entertaining
account Of the so-called fire-eaters. Fire,
he said, might be handled with impunity it
various conditions be complied with, and,
as he repeatedly remarked, elf you know
how" Sometimes the skin is naturally hard,
thick, and callous, so that highly-heated sub
stances may he held for some time without
danger; or non-conductors might he inter-
posed-a fact which he illustrated by cover
ing his hand with charcoal and placing
thereon lump of red-hot iron. Certain
chemical substances being applied to the
skin, will, when in contact with other SUBJ
stances of high temperature. yaporize, form
ing a cushion of vapor which protects the
part from injury. To prove the fact the
speaker, first dipping his hand into turpen-
tine TO cleanse the skin, and then into ether,
cody plunged it into a tank Of boiling water
and removed an egg. Then, rs concluding
experiment, he moistened his hand with
strong ammonia and dipped his fingers into
molten lead, hot enough TO inflame paper,
and finally poured the molten metal on bis
palm, scattering it about as if it were quick
silver. G i J.