feme Experiments made with an Air-pump. 629 
Subfiances put into die receiver. 
Weight 
when put 
into the 
receiver. 
Degrees of exhauf- 
tion according to 
Variation in 
weight 
during the 
experiments. 
f 
Barom. 
gage- 
Pear- 
gage. 
100 grains 
i ‘34 
100,000 
left 2 grains. 
80 grains 
26 8 
280 
gained 2 grs* 
1O0 grains 
H 7 
100,000 
loft 2 grains* 
exp. xii. A piece of white lea--* 
ther, frefh from the leather- > 
fellers, — — J 
exp. xiii. The fame piece of *1 
leather, dried by the fire till 
it would lofe no more of its 
weight,. - — - — 
exp. XiV. The lame piece of 
leather held in che fteam of 
hot water till it had regained 
the 20 grains it had been de- 
privedof, • — •- — 
In this laft experiment it was full three quarters of an 
hour before the leather regained the twenty grains of 
weight, although it was held very near the furface of 
the hot water. 
Whenever I have allerted, that the degree of exhaus- 
tion, according to the pear-gage, was fo great as 1 00,000, 
I only gueffed it to be thereabouts, for my gage is not 
graduated to more than 4000; but, that it may be feen 
what reafon I had to fuppofe it at 100,000, I have 
brought my pear-gage filled in this laft experiment, for 
the infpedlion of the gentlemen prefent. 
EXPERIMENT XV.. 
The fame piece of leather ufed in the eleventh expe- 
riment was put into a damp cellar, where it was left till 
the 
