C H E M 
Authorities. 
Water . rcooo Crawford. 
Cows milk.. '9999 
Venous blood. *8928 
Azotic gas .. '7936 
Hide of an ox with the hair . . . *7870 
Lungs of a fheep. '7690 
Mufcular fielh of an ox' . . . . ’7400 
Alcohol. '6021 
Rice. '5060 
Horfe-beans. '5020 
Spermaceti oil. '5000 
Fruit of the pine-tree. ’5000 
Peafe.: . . . '4920 
Wheat.. "4770 
Barley. "4210 
Oats. ’4160 
Sulphuric acid. '4290 
Pitcoal. '2771 
Charcoal .. '2631 
Chalk. '2564 
Ruft of iron. ‘2500 
Walked diaphoretic antimony . . *2272 
Oxyd of copper nearly freed from air '2272 
Quicklime. "2229 
Cinders. ’1923 
Alhes of pitcoal. *1855 
Ruft of iron nearly freed from air ’i666 
Wafhed diaphoretic antimony do. -1666 
Alhes of elm wood. ’1402 
Oxyd of zink nearly freed from air ’1369 
Iron. ‘1269 
Brafs. "1123 
Copper. ‘i in 
White oxyd of tin almoft free of air '0990 
Zink. '0943 
Allies of charcoal. -0909 
Tin. . . . . '0704 
Yellow oxyd of lead almoft free of air -0680 
Antimony. ’0645 
Lead. '03 52 
Snow. '9000 Magellan. 
Ice. '9160 Humboldt. 
Bar-iron ......... ’1099 Lavoilier& 
Rock-cryftal. ’1929 La Place. 
Mercury. •0290 
Quicklime. . ’2168 
Mixture of 9 parts of water with 16 
of quicklime. '439 1 
Sulphuric acid,having the fp.gr. ofi'87 1 ’3345 
Mixture of 4 parts of this acid with 
3 parts of water. '6031 
Mixture of 4 parts of the fame acid 
with 5 of water. ‘6631 
Nitric acid, having the fp. gr. of i - 29895 -6613 
Mixture of 9! of this acid with 1 
of quicklime. '6189 
Mixture of 1 part of the nitrat of 
potalh with 8 parts of water . . -8167 
Sulphur. -1830 Kirwan. 
Lintfeed oil. -5280 
Cryftallized muriat of foda . . . -2260 Gadolin. 
Saturated folution of muriat of foda in 
water (containing 372 parts of the fait 
to 1000 parts of water) .... '793° 
Fourcroy feems to be of opinion, that caloric to feme 
fubftances imparts additional ponderofity. But fo far 
from caloric adding to the weight of bodies, it would 
appear, from an experiment very accurately related by 
Dr. Fordyce, that caloric ditninijbes the weight of the 
bodies into which it enters, as latent caloric. It was found 
in this experiment, that 1700 grains of water acquired 
by freezing the additional weight of very nearly i-i6th 
part of a grain. The water and ice were both weighed 
S T R Y. 187 
at the temperature of 32 0 . (Philofophical Tranfaflions, 
2d Part, for 1785.) This experiment has been confirm¬ 
ed, in a very fatisfadtory manner, by Sir Benjamin 
Thompfon. Water was counterpoifed with fpi.it of 
wine, and the apparatus was then placed in a low tempe¬ 
rature, where the water was frozen, while the fpirit of 
wine remained liquid. The water, as in Dr. Fordyce’s 
experiment, became heavier, in confequence of its con- 
verfion into ice. It is proper at the fame time to ftate, 
that, in a fimilar experiment, Lavoilier found no differ¬ 
ence between the weight of the ice and water. The 
quantity of water which he made ufe of in this experi¬ 
ment was one pound, and it weighed precifely as much 
before as it did after it was frozen. The balance he em¬ 
ployed was fenfible to the difference of i-iotb of a grain 
when loaded with eighteen or twenty ounces. (Me- 
moires de l’Academie de Sciences, 1783, page 419.) An 
attempt has been fince made by Dr. Higgins, to afeer- 
tain whether the caloric emitted during the flaking of 
lime produces any fenfible difference in the weight of 
the materials employed; but the experiment failed. 
Since latent caloric appears, from Dr. Fordyce’s ex¬ 
periment, to diminifh the gravity of bodies, there is 
reafon to enquire, whether f ree caloric has not a greater 
tendency to afeend than to defeend. M. Pictet has made 
feveral experiments to afeertain this point. A cylindri¬ 
cal bar of copper was placed vertically within a glafs 
tube, which was afterwards exhaufted of air, by means 
of the air-pump. The concentrated rays of the fun 
were thrown upon the middle of the cylinder, and the 
fucceffive dilatations of two mercurial thermometers, 
connected with its two extremities, were carefully ob¬ 
served. It was found, that, in the fame times the mer¬ 
cury in the upper thermometer rofe to a greater height 
than in the under one; and, after the light was with¬ 
drawn, the under thermometer funk fafter than the up¬ 
per one. EJfai fur le Feu, chap. 2d. 
M. Pidftec has publiflied feme experiments on the calo¬ 
ric produced by friction. He had imagined that the ca¬ 
loric evolved by friftion was obtained from a mechani¬ 
cal decompofiticn of the air between the rubbing furfa- 
ces; but he found that the fame degree of friftion railed 
the thermometer iomewhat higher in vacuo than in the 
open air. This difference wasno doubt occalioned by the 
greater conducing power and greater capacity of the air 
than of the vacuum ; but ftill the experiment lliowed 
that his firft conjecture had been unfounded. In hisfub- 
fequent experiments, it appeared that more caloric was 
evolved by the fridtion of foft bodies againft this fric¬ 
tion-machine than when hard bodies were employed ; 
and the fridtion of a fmall quantity of cotton upon the 
bulb of his thermometer, increases the effect molt re¬ 
markably. EJfai fur le Feu, cliapitre 9. 
Notwithftanding thele various refearches into the na¬ 
ture and principles of light and heat, and the very able 
difcuifions of the phlogiltic and antiphlogiftic writers on 
chemiltry, it is to be lamented that no abfolute decilion 
has yet been made on this long controverted fubjeft. 
After the ingenious Lavoifier had fuccefsfully combated 
and refuted the phlogiltic lyftem of former chemifts, 
M. Bucquet and Macquer endeavoured to rellore the. 
fame dodtrine under a different form. 
M. Bucquet, in his latter courles cf lectures, explains 
upon this principle the greater part of the phenomena of 
combuftion, calcination, and reduction .of metallic calces; 
but it does not afford adequate reafons for the flame 
which is produced by bodies in a ftate of ignition, nor 
the rapid motion and other changes that attend it. M. 
Macquer, though well aware of tne influence of the mo¬ 
dern diicoveries on chemical theory, advanced an opinion 
that they do not entirely overthrow the phlogiltic doc¬ 
trine of Stahl; and he has found means to unite the pneu¬ 
matic doctrine of the moderns, with that of phlogifton, 
by confidering this principle as light fixed in bodies. After 
having Ihown that pure light, luch as is emitted by the 
