28 On Respiration and Animal Heat. 
expired ; Dr. Menzies found 6 oz.; Mr. Aber- 
nethy, 90z.. Lavoisier, partly by experiment, 
and partly by theory, in one of his memoirs, 
estimates the water exhaled from the lungs 
daily at 28 0z.; but im some instances, he 
estimates more, in others, less. 
This diversity of results amongst the earlier 
physiologists was not to be wondered at; but 
it is somewhat surprizing, that after the re- 
cent discoveries on the nature of steam or 
aqueous vapour, any material uncertainty 
should still remain respecting the quantity of 
water exhaled from the lungs in a given time. 
Nothing is more obvious and easy than to eal- 
culate, @ priori, the precise quantity of aque- 
ous vapour in a given quantity of air expelled 
from the lungs. At the temperature of 98°, 
the utmost force of aqueous vapour is nearly 
equal to 14 inches of mercury, as appears from 
Tables of various authors.* The force of 
aqueous vapour existing in the atmosphere is 
various; but the medium quantity in this cli- 
mate may be estimated at 30 of an inch of 
mercury, due to the temperature of 44°. (See 
Memoirs, vol. 1. second series, page 243.) 
New it is certain that the air in the small 
* See Memoirs, vol. 5, page 560, Bettancourt’s Exe 
periments in-Encycl. Brit. or Hutton’s Math, Dic. &c., 
