[ I + I 3 
adion of the diaphragm and abdominal mufcles, and 
of the fotus of their generally neighbouring parts : 
requifites, as has been imagined, towards the carrying 
on their feveral fundions, for the benefit of the ani- 
mal oeconomy. 
George Carlifle. 
Received May 12, 1766. 
XIX. Three Papers , containing Experiments 
on faEUtious Air , by the Hon . Henry 
Cavendifh, F. R. S. 
Read May 29, Nov. 6.T^ Y faditious air, I mean in general 
and Nov. i 1 7 . any kind 0 p a j r which is contained 
in other bodies in an unelaftic ftate, and is produced 
from thence by art. 
By fixed air, I mean that particular fpecies of fac- 
titious air, which is feparated from alcaline fubftances 
by folution in acids or by calcination; and to which 
Dr. Black has given that name in his treatife on 
quicklime. 
As fixed air makes a confiderable part of the fubjed 
of the following papers ; and as the name might in- 
cline one to think, that it fignified any fort of air which 
is contained in other bodies in an unelaftic form ; I 
thought it beft to give this explanation before I went 
any farther. 
Before. 
