433-4 
long enough to keep a good part of 
it above the furface cf the water in 
the time the brim of it is fliding 
under water over the fkin. In this 
way one may fee an immenfe num- 
ber of very minute bubbles» rife 
continually to the top of the water 
in the inverted glafs, and gather 
in larger bubbles at the top. By 
this method I colleéted, in a little 
time, from my arms, a meafure of 
this air, which feemed to be partly 
fixes air, "as dt was-fomewhat ab- 
farbed by thé water; at leaft, I 
thotight to find the mafs of ital- 
ways lefs than it was before. This 
air put to the nitrous teit’was found 
far from being good reipirable air; 
for one ieafare? of it, with one of 
nitrous aif occupied, 1.46. 
I took a quantity of air in 
pie manner from. the arms: ofa 
K3 S healthy 
