C *57 3 
inflammable air, and which is reprefented in Fig. 3. 
The cylinder was weighed carefully before and after 
the air was forced through} whereby it was found to 
have increafed 1 grain in weight. The empty (pace in 
the cylinder was 248 grains, the differenceof weightof 
which quantity of common and inflammable air is 4 
of a grain. Therefore the real quantity of moifture 
condenfed in the pearl-afhes is 14 grain. The weight 
of 1 92 ounce meafures of inflammable airdeprived of its 
moifture appears from the former experiments to be 
104. grains; therefore its weight when faturated with 
moifture would be 1 14 grains. Therefore inflam- 
mable air, in that ftate in which it is in, when kept 
under the inverted bottles, contains near ± its weight 
of moifture; and its fpecific gravity in that ftate is 
7840 times lefs than that of water. 
I made an experiment with defign to fee, whether 
copper produced any inflammable air by folution in 
fpirit of fait. I could not procure any inflammable 
air thereby; but the phenomena attending it feem 
remarkable enough to deferve mentioning. The 
apparatus ufed for this experiment was of the fame 
kind as that reprefented in Fig. 1. The bottle A was 
filled almoft full of ftrong fpirit of fait, with fome 
fine copper wire in it. The w'ire feemed not at all 
adted on by the acid, while cold ; but, with the 
affiftance of a heat almoft fufficient to make the acid 
boil, it made a confiderable effervefcence, and the air 
pafied through the bent tube, into the bottle D, pretty 
taft, till the air forced into it by this means feemed 
almoft equal to the empty lpace in the bent tube and 
the bottle A : when, on a hidden, without any fenfible 
alteration of the heat, the water ruflied violently 
through 
1 
