f ras j 
air, Winds blowing from difteretit 
quarters, and conveying airs of dif+ 
ferent qualities, from diftant coun- 
tries, and many other operations of 
nature, unnoticed as yet? . 
Water itfelf, one of the fimpleft 
and the moft unalterable fubitances 
porns ess to be changeable 
o contair foie atin gs which may 
fe transformed into” this air by 
the influence of the day-light; for 
the green vegetable fubftance, which 
ferves as a kind of laboratory, in 
which this falubrious air is produced, 
is formed from the water#itfelf. 
Abbe Fontana made a great many 
experiments tending to examine the 
air extracted from different waters 
by heat. I was prefent at thefe 
experiments in the fummer of 17773 
being then at Paris. He extracted 
s — from 
