[ 436 ] 
nature clofely ; and know that the regularity of her 
proceedings is conne&ed with a forefight whch is 
limited to us, by nothing but the limits of our abi- 
lities in tracing it ; and confequently, when art at- 
tempts to imitate nature, it can only fucceed in as 
much as it is attentive to imitate her care. 
72. I believe that the hygrometer may farther 
acquire a perfection of the fame kind as that which, 
in conformity to an idea of my worthy friend Mr. 
Le Sage, I have given to the thermometer ; that is, 
that we may make its degrees correfpond with equal 
differences in the humor; as I have made thofe of 
the thermometer correfpond with equal degrees of 
heat. The way in which I think this might be done, 
would be to fufpend near one of the hygrometers, in 
a proper veffel which fhould be placed in one of the 
fcales of a balance that turns very eafily, fome fub- 
ftance remarkably greedy of the humor ; the aug- 
mentations or diminutions of weight in which fub- 
Itance, might be compared with the going of the 
hygrometer, firfl in the fame, and afterwards in dif- 
ferent degrees of heat. I hope too, that by a fre- 
quent repetition of thefe obfervations, at times when 
the variations of the humor are more or lefs fudden, 
we fliall at laft fucceed in correcting the errors that 
may attend them, from the lofs of its own matter 
the fubftance made ufe of may probably fuffer by 
evaporation.' 
73. Thefe are not the only remarks I have made 
upon my inftrument, but I did not care to mention 
any but fuch as have appeared to me moft certain. 
The others are uncertain, and require longer obfer- 
vations. I fliall only add therefore, that it will hill 
