[ 201 ] 
pear likely that this inftrument will ever be made- 
capable of fo accurate an agreement, as mercurial 
thermometers are made to be 5 yet, if we can re* 
duce all the difagreements of an hygrometer within 
-^",,th part of the wdiole fcale, it will probably be of 
ufe in fome philofophical enquiries, in lieu of in- 
flriiments which have not as yet been reduced to 
any common fcale at all. 
Dejertption of the Hygrometer, 
Fig. 1 and 2, ABC is an orthographick delinea* 
tion of the whole inftrument feen in front in its 
true proportion. 
D E is that of the profile, or the infirument feen 
edgeways. 
F G, in both, reprefents a flaxen Cord, about 35 
inches long, fufpended by a turning peg F, and at- 
tached to a loop of brafs wire at A, which goes 
down into the box cover H, which defends the in- 
dex, 6cc. from injur}% and by a glafs expofes the fcale 
to view. 
Fig. 3. {hews the inftrument to a larger fcale, the 
upright part being fhortened, and the box cover re- 
moved j in which the fame letters reprefent the fame 
parts as in the preceeding figures ; G I are two 
loops or long links of brafs wire, which lay hold of 
the index K L, moveable upon a fmall fludd or 
center K. The cord F G is kept moderately {train- 
ed by a weight M, of about half a pound avoir- 
dupoize. 
It is obvious, that as the cord lengthens and fhortens, 
the extreme end of the index rifes and falls, and 
fucceflively pafles over 
VoL. LXr. J) d N 2 
