C 7 3 
referved this for my Study ; where, or in any inclofed 
Place, it does well enough, and may be very ufeful 
ki the following Refpeds ; as, 
1. To examine, in Cafes of Sicknefs, the c Damp- 
nefs of Rooms. 
2. To examine Damps in fabterraneous Cavities , 
being let down with a Weight , where a Light would 
fometimes fet the Place on Fire. 
3. Toobferve the proper State of Dry nefs in Ware' 
houfesy Wine-vaults , Studies , where Damps would 
be detrimental and pernicious. 
4. To examine the Strength of fudden Fogs , and 
the comparative Dampnefs of particular Situations. 
As a Succedaneum to this, I thought upon a ftati- 
cal one; it recurring to my Mind, That the Weight 
and Moifture of the Air being but two Properties of 
one and the fame Body, a ft at ical Hygrometer (ce- 
teris paribus) promifed the beft Afhftance towards a 
more complete Knowledge of the Barometer , which 
ads upon ftatical Principles ; and that thefe two Ma- 
chines mull: have a reciprocal Correfpondence with 
each other. I then remember’d, that the great Mr. 
Boyle had mentioned fomething of this Nature; after 
confulting whom, I made the following Machine y 
ading upon his Principles, but formed in a Manner 
differing from his. 
I cauled a Balance to be made to turn with half 
a Grain , ordering that the Axis of the Balance fhould, 
on one Side, be drawn out to the Length of one Inch, 
and its End to be furnifhed with a Male Screw , to 
which a light Index with a Female Screw might be 
fixed. I had t\\\s Balance fa&znzd in a JVainfcot Box, 
twelve Indies in Length, nine in Diameter, and four 
