, 1877-05-04
The Analysis of a Diamond.

The great French chemist, Lavoisier,
undertook the examination of the dia-
mond, and it is worth while noticing
how carefully he went to work, how he
proceeded slowly from one step to an
other, in logical sequence, until he ar
rived at the true solution of the ques-
ton he had undertaken to investigate
that is, until he was able to tell us ex-
actly what happened when the diamond
evaporated in the free fire, and why it
did not do so when surrounded by
charcoal. In the first place he evapora-
ted the diamond by means of the burn
ing glass, and he observed that no visi-
bic vapor or smoke was given off, but
that the diamond disappeared. He
thought that perhaps the solid diamond
had In some way been dissolved by the
water, and that by evaporating the wa
ter, which was in the lower part of the
bell jar in which he burnt his diamond,
he might obtain the constituents of the
diamond in solid form; but he found
that no solid residue was left on evapo-
ration, and thus no trace of the dia-
mond could be found.
His next experiment was that of plac-
ing a diamond in the focus of a less
powerful lens than the one he had form
erly used, so that the diamond was not
heated to so high temperature as be-
fore, again placing it, however, in a bell
jar over water. He then found that the
diamond, when not heated quite 50
strongly, lost only about one quarter of
its weight; it did not disappear alto
gether, but the remarkable fact was no.
ticed that it became covered with a
black substance which Lavoisier de-
scribes as being, exactly like lampblack
or SCOT, so that it dirtied the fingers
when touched, and made black mark
upon paper.
Hence Lavoisier concluded that the
diamond is susceptible of being
brought, under certain circumstances,
into the condition of charcoal, SO that it
really belongs to the class of combusti-
BILE bodies. He was, however, yet far
from having proved this point, and he
went on experimenting. He next
measured the volume Of air in which
he was going to burn the diamond, and
found it to be eight cubic inches. Then
he burned the diamond in this volume
of air by means of lens, and found
that the air had diminished to a volume
Of six cubic inches, thus showing that
tho air had undergone some change by
the combustion of the diamond, and
that two out of the eight volumes of air
had disappeared.
The next experiment he made was to
examine the condition of the air in which
the diamond had been evaporated.
What changes had gone on in the air
in consequence of the evaporation Of
the diamond? After allowing the glass
in which he had burned the diamond to
stand for four days, he poured clear
lime water into the jar in which the dia-
mond had been evaporated, and he says
this lime water was at once precipitated
in the same manner as if it had been
brought into contact with the gas
evolved in effervescence and fermenta-
ton, or that given off in cases Of metal
lie reduction. Here, then, he had got
on the track of what he wanted.
Hitherto, the diamond had apparently
disappeared, and nothing was found to
account for its disappearance; but now
he had found that there was something
contained in the air in which the dia-
mond was burned which was not con-
tanned in the air before.
The next step he took was to examine
the white precipitate or powder which
was formed, and he found that the SUBJ
stance thus precipitated from lime wa
ter, by the air in which the diamond
had been evaporated, efervesced on
treatment with acid, and evolved what
was then known as fred air, but which
we now know as carbonic acid gas.
Here, then, he completes his proof,
showing that exactly the same effects
are observed when charcoal is expert
mented upon, instead of diamond.
Lavoisier had now run his quarry to
earth; he had determined exactly what
it is that is formed when a diamond is
burned. He has shown that diamond
when burned produces exactly the same
substance that is produced when COM
mon charcoal is burned, and he, there
fore, legitimately concludes that the
diamond is only another form of the
element carbon. The reason that the
diamond did not burn in the furnace
when surrounded by a mass of charcoal
was that the air, or rather the oxygen of
the air, could not get to the diamond,
because. it was kept off by the charcoal,
which burned instead of the diamond
Professor Roscoe.
A FISH CATCHING SPIDER. Just be-
fore the late war 1 was at Col. Oakley