[ + 5 8 ] 
fcer) 17 degrees lefs than it was in the months of 
Augu ft and September. 
108. I hope this paradox will be explained, and 
that the principles which may clear it up will draw 
ufeful confequences along with them. Thofe phi- 
lofophers who look upon evaporation as a diffoluticn 
of water by air in the manner of menftrua, that 
is, by affinity, will ealily apply their principle to the 
folution of part of thefe phenomena. The diffo- 
kition is greater when the menftruum is warmer, and 
confequently the air mud keep a greater quantity of 
water in diftolution, and fuffer a lefs part of it to 
be precipitated, in fummer than in winter. I can- 
not but allow that this fyftem is extremely fpecious, 
and that many phenomena are very happily ex- 
plained by means of it. This is what Mr. le Roy 
has ffiewn us in the memoir 1 have already quoted ; 
"in which, without contending that air really adts as 
a menftruum with refpedtto water, he demonftrates, 
by a parallel very well kept up, that all the chemi- 
cal expreffions concerning diffolutions may with 
propriety be applied to defcribe the feveral phe- 
nomena he examines, relative to the elevation and 
lufpenfion of water in air, as well as to its precipi- 
tation under different forms. 
109. If it was not too common a pradtice, to 
conclude things from words, I ffiould in fadt think 
thefe chemical expreffions very conveniently adapted 
to explain a number of thefe phenomena. But I 
have rejedted them here, on account of this conft- 
deration ; that when I took in a greater number 
of phenomena, I found them no longer accurate, 
any more than the general idea of the diffoiu- 
