i; r i Sir Benjamin Thompson’s Experiments 
11 ate thofe bodies of water, and to caufe them to yield the great 
abundance of air which they produced. 
It was full more difficult to account for the purification of 
the air in the experiments with wool and fur, and human hair ; 
efpecially, as in fome of thefe experiments the water had not 
fenfibly changed colour, nor did it -appear to have loft any 
< thing of its tranfparency. lit is true, in thefe cafes, the quan- 
tities of air produced were very final! ; but yet its quality was 
. better than, that of common air, and confiderably fuperior to 
that of the air exifting in the water, previous to its being ex- 
poled to the aCtion of the fun’s light, iln ffiort, it wasdephlo- 
giflicated in the experiment ; but the manner in which tlm 
was done is very difficult to afeeftain. 
With a view to throwing fome new light -upon this- intricate 
fubject, I made the following experiments. 
; Experiment N° 26. 
Concluding that if filk and other bodies, ufed in the fore- 
going experiments, actually did not. contribute any thing, con- 
iidered as chymicai fubitances, .< in the. procefs of the production 
of pure air yielded by water.; but if, on the contrary, they 
aCted merely as .a. mechanical aid in the Jeparation of the air 
from the water, by affording a convenient furface for the air 
to attach itfelf to ; 1 in this cafe, any other body, having a 
large furface, and attracting air in water, might be made ufe of 
inftead of filk ini the experiment, and pure air would be 
furniffied, though the body fo made ufe of ffiould be totally 
incapable of communicating any thing whatever to the water. 
To afeertain this ■ faCt, walking the great globe (containing 
.296 cubic inches) perfectly clean, and filling it with frelh 
fpring water, I introduced into it a quantity of the fine flexible 
a thread 
