393 
C H E M 1 
The crucible was {hut by its iron ftopper, which was for¬ 
cibly thruft home, that as little air as poffible might re¬ 
main in the inhde. 
Grammes. 
The crucible and ftopper weighed together - 55^ 
The iron filings which covered the diamond 2 
Total weight of the iron furrounding the diamond 57-8 
After having cut off the excofs of the ftopper, the cru¬ 
cible was placed alone, and without the addition of any 
iurrounding matter, in a very Imall Heffian crucible, and 
the latter in a fecond crucible of the fame earth ; but the 
fpace between the two latter crucibles was filled with lili- 
ceous fand free from all ferruginous particles. In the laft 
place, the large crucible was luted with earth arifing from 
pounded crucibles and unbaked clay, and the whole was 
expofed about an hour to a three-blaft forge fire. The 
whole being cooled, we found, in the interior Heffian 
crucible, the iron converted into an ingot of call fteel, as 
Ihewn at fig. 6. It formed, with the ftopper and filings, 
but one round mafs well terminated, fome few globules 
excepted, which were detached, and which weighed only 
884. milligrammes. 
Grammes. 
The ingot of caft fteel weighed - - 55- 500 
The detached globules ... °-SS4 
Total weight of the fteel obtained - - 56- . -4 
The iron and the diamond weighed, before the opera¬ 
tion, 58 707 grammes 5 from which it follows that there 
was a lofs of iron about 2-425 grammes. This iron had 
given to the Heffian crucible the colour of plumbago. 
The fufion of the iron being fo far perfedt as to fhew 
on its furface the rudiments of the moft beautiful cryftal- 
lization, it is not poffible to think that any part of the 
diamond could have remained in the infide untouched, 
or that it was not in the moft intimate ftate of combina¬ 
tion. The difference of the fpecific gravity oppofes fuch 
an idea. 
Some perfons having expreffed a defire to fee the in¬ 
fide of the ingot, it was broken on the anvil, which was 
not effected without feveral blows from a very large ham¬ 
mer. It divided itfelf into two fragments, which were 
exhibited at the next fitting. The fradture appeared per¬ 
fectly uniform, and of the moft beautiful grain. 
Thus the diamond difappeared by the affinity which 
iron exercifed on it by the help of the high temperature 
to which they were both expofed, in the fame manner as 
a metal difappears in the alloy of another metal. The 
diamond, therefore, has furnifhed here the fame principle 
as carbon, fince the produdt of the union has the fame 
properties. 
The whole of the apparatus for this experiment, which 
is very fimple, is ffiewn in the plate, as follows : A, fig. 4, 
is the plan of the iron crucible. B, a fedlionof this cru¬ 
cible. C, fig. 5, the ftopper of the crucibles D, E, fig. 6, 
ingobof caft fteel feen in perfpe&ive. The fpot formed 
by the nitric acid on the poliffied part is reprefented at a>. 
Thofe who have never turned their attention to the 
phyfical fciences, to eftimate at leaft their influence on 
public felicity, are difpofed to treat as vain curiofity la¬ 
bours which are not immediately diredted towards a near 
objedt of new enjoyment. What would have been their 
aftonifhment had they been told, that refearches on the 
nature of the diamond would one day produce truths, 
which might give rife to happy changes in the pradtice 
of the moft familiar arts ; in the preparation, and in the 
employment of the coarfeft combultibles! Such, how¬ 
ever, are the confequences that may arife from the belt 
known properties of the effential principle carbon in its 
different ftates. For an account of the new meafures and 
weights lately adopted in France, and occafionally men¬ 
tioned in the foregoing treatife, fee the article Mea¬ 
sure. 
Vos.. IV. No. 205. 
S T R Y. 
The CALORIMETER op LAVOISIER and La 
PLACE. 
-Caloric, or the matter of heat, confidered as accumu¬ 
lating in a greater or lefs quantity in fubftances of diffe¬ 
rent natures, but of equal mailes, and in which it ac¬ 
quires the fame expanfive force, is often termed fpecific 
caloric : it is the relation of the quantities of heat necef- 
fary to raife different fubftances of equal maffes to the 
fame temperature. 
To difcover the quantity of caloric contained in diffe¬ 
rent bodies, Meffrs. Lavoifier and La Place have invented! 
a fimple but admirable inltrument, to which they gave 
the name of calorimeter, or apparatus for meafuring the 
relative quantities of caloric, contained in bodies, or 
what they term latent beat, as ampiy deferibed under the 
head Caloric, p. 181, See. of this treatife. The inftru- 
ment is founded upon the following principles: I. That 
if any body be cooled to the freezing- point, and then, 
expoled to an atmofphere of 88-25, it will be heated gradu¬ 
ally from the turface inwards, till at laft it acquires the 
fame temperature with the furrounding- air. 2. That, it 
a piece of ice be placed in the fame fituation, thecircum- 
ftances are quite different; it does not approach in the 1 
fmalleft degree towards the temperature of the circumam¬ 
bient air, but remains conftantly at 32 0 , or the tempera¬ 
ture of melting ice, tilt the laft portion of ice be conv- 
pletely melted : in other words, that ice abforbs all the 
heat communicated to it, without communicating it to 
otherbodies,until the whole be melted; and, confequently, 
that we may calculate the degrees of heat communicated* 
by the quantity of ice which is melted.. 
This phenomenon is thus explained: To melt ice, or 
reduce it into water, it mult be combined with a cer¬ 
tain portion of caloric : the whole quantity firft commu¬ 
nicated, is fixed at the furface of the external layer of 
ice ; this it diffolves, combining with it to form water j 
the next quantity combines with the fecond layer, and 
forms it into water; and fo on fucceffively, till the whole 
is diflolved and converted into water'by being combined 
with heat; the laft atom ftiil remaining at its former tem¬ 
perature, becaufe the heat never penetrates fo far, as long 
as any intermediate ice remains to be melted. 
Upon theft: principles, if you imagine a hollow fphere 
of ice at 32 0 , priced in an atmofphere of 54 or 5 5 0 , and 
containing a fubftance at any degree of temperature above 
freezing, it will follow, 1. That the heat of the external 
atmofpnere cannot penetrate into the internal cavity of 
the fphere of ice. 2. That the heat of the fubftance 
placed cannot penetrate outwards beyond it, but will be 
flopped at the internal furface, and continually employed 
in melting fuccefiive layers of ice, until its temperature 
is reduced to 32 0 , by having all the heat above that tem¬ 
perature carried off by the ice. 3. If the quantity of 
water within the fphere of ice during the experiment be 
carefully collefted, the weight of the water will be exa£Hy 
propoitional to the quantity of caloric loft by the body 
in paffing from its original temperature to that of melting 
ice ; it being evident, that a double quantity of caloric 
wouid have meited a double quantity of ice ; and that 
the quantity of ice meited is an exadl meafur'e of the 
quantity of caloric employed to produce the etteft; and 
of the quantity loft by the only fubftance from which it 
could be obtained. The foregoing fuppofition is only 
made to explain more readily the nature of the experi¬ 
ments to be made with the above-mentioned apparatus, 
which is fo contrived, 1. That the ice abforbs all the ca¬ 
loric difengaged from the bodies under examination. 
2. That the ice is lecured from the aftion of every other 
fubftance which might facilitate its fufion; and, 3dly, To 
coheift with care the water produced by the fufion. 
The apparatus confifls of three circular veffels, nearly 
inferibed in each other, as reprefented in the Chemical 
Elate XI. fig. 1, and 2 ; by which means three vacancies 
5 H. are 
