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tion of water by air.. I have given tjhe deafens (for 
this in my work, -upon the modification of the at- 
mosphere j andfiuil only repeat here, that thefe mo- 
difications of the humor appear it© me almaft intirdy 
to be prod need by the igneous fluid ; and that if the 
air has any fbare in them, it is only as heing an 
elafiic fluid. l he particles of thefe fiuids, each ac- 
cording to its degree of power, ftrike, feparate, and 
draw along with them thofe of the humor, and com- 
municate to them the elaflicity they poflefs ; in the 
lame manner as they do to the particles of all volatile, 
and like wife of all fixt fubftances which they cor- 
rode and decompofe. 
i io. This fyltem will not only furnifh a folution 
of the paradox which engages our attention, but will, f 
believe, carry us much farther. The heat of the 
fummer keeps the humor in very great agitation; 
and though there is more of the humor at this fea- 
fon than in winter, yet this heat will not allow it to 
continue either as long a time, or in as great a quantity, 
Upon the bodies or in their pores. That is the 
reafon why the hygrometer falls lefs. But we fee at 
the fame time, that the portion of the humor which 
does fojourn, and which I call the adtive part, has 
more power to dilatate the bodies, from the greater 
degree of motion imprefied upon it by a greater 
heat. Confequently the dilatation of the bodies, from 
this caufe, will be in a compound ratio of the quan- 
tity of humor, and of its adtive force, or of the heat. 
And if, for infiance, we compare any fummer’s day, 
in which the hygrometer in open air is at the fame 
degree as on anys winter’s day, the air on the fum- 
mer’s day will contain more humor than on the 
Vol. LXIII. O o o winter’s 
