[tot] 
the 0^1 of Vitriol is fatiated, in the moijiefi weather ; 
it afterward retains or loofe^ its acquired weight as 
the Air proves more -or lefs moiji. 
Thus the one grain above meiition'd after its full 
Increafe of ten varid it'j equilibrium^ vi^. m 'dry wea- 
ther, the n^eights , in moift ^ the liquor did cooftantly 
preponderate, and that fo fenfihly that the tongue of 
the Ballance of i i Inch long defcrib d an Arch of 
Variation to ^ of an Inch compafs ; { which Arch would 
have been 2 ^ Inches ( had the tongue been but ont 
foot in length ) even with that little quantity of Li- 
quor, fo that if more Liquor expanded under a large 
Surface be us'd, the minutejl alteration of nheather muft 
needs very much more affed: it, and a bare^ pair of 
Scales will afford an Hygrefope as nice perhaps as any 
yet known. 
This Ballance mzj ho, contrived tjvo ways, either ftich 
whofe pin fliould be in the middle of the Beam, with a 
vtxj fender tap. ring tongue of a foot or one foot and 
a halt long, pointing to the divifions on a broad Arch d 
plate fix t ahovi in the handle according to figure the 
third in the Table-, or elle the Scale with the Liquor 
may be hung to a point of the Beam very near the 
pin, and the other extream made fo long as to mark 
a large Arch on a board plac'd conveniently for that 
purpofe, as the fourth figure r pre/ents sThQ Scale in ei- 
ther may be a concave Glafs of fur or five Inch.s Di- 
ameter, 
Laftly, on the divifion of the /^ rches fliould be in- 
ferib'd the different temperature of the Air ihewn by the 
Liquor. The fifth Figure gives the lineament of ano- 
\ ther Hygrofcope made of a Viol-ilring running 
\upon pullies, and fufpending a bullet fixt to the fliorter 
end of an Index, whofe other extremity is fo long as 
Vo defcribe a long Arch by the falling and rif^ng of 
^e Bulks: u^ontht Sr etching sind Shrin.l(i?/g of the String 
K2 ' which 
