.Mzc2.NzUwNA

[ 55 ] ber) 17 degrees less than it was in the months of August and September. 108. I hope this paradox will be explained, and that the principles which may clear it up will draw useful consequences along with them. Those phi≠ losphers who look upon exaporation as a dissolution of water by air in the manner of menstrua, that is, by affinity, will easily apply their princple to the solution of part of these phaenomena The disso≠ lution is greater when the menstruum is warmer, and consequently the air must keep a greater quantity of water in dissolution, and suffere a less part of it to beprecipitated, in fummcr than in winter. I can≠ not but allow that this system is extremely specious, and that many phznomena are very happily ex- plained by means of it. This is what Mr le Roy has shewn us in the memoir I have already quoted ; in which, without contending that ai r really acts as a menstruum with respect to water, he demonstrates, by a parallel very well kept up, that all the chemi≠ cal expressions concerning dissolutions may with propriety be applied to describe the several phae≠ nomena be examines, relative to the elevation and suspension of water in air, as well as to its precipi≠ tation under different forms 109. If it was not too common a practice, to conclude things from words, 1 should in fact think these chemical expressions very conveniently adapted to explain a number of these phaenomena. But I have rejected them here, on account of this consi≠ deration; that when I took in a greater number of phaenomena, I found them no longer accurate, any more than the general idea of the dissolu≠ tion