C l8 7 3 
To this Hygrometer I fixed a fmall Index, fuch 
as is common in Mr. Hauksbee's Barometers, to flip 
up and down on a Wire, as is reprefented at K. 
Fig . 4. reprefents another Method I employed to 
increafe the Power of the Deal Rod. This may be 
fixed in a much firraller Compafs, and yet is no lefs 
capable of ftiewing the minute Differences in the 
Moiflure or Drynefs of the Air than the other before 
defer ibed. 
The Deal Rod in this was managed and faflened 
in the fame manner as was fliewn before. I likewife 
applied a Lever A B 2 ) to the Top thereof, exactly 
of the fame Dimenfions as in the other 5 but, inftead 
of a feeond Lever, I placed a graduated Circle, with 
an Index thereto like that of the Minute-Hand of a 
Clock. 
* This I fixed to a fmall Axis , which was moved one 
Way by a filken Thread wrapped twice or thrice 
round it, whereof one End was tied to the longer End 
of the Lever at O, and the other Way by the Gra- 
vity of the Weight W. 
And here, if the Length of the Index R S be 15 
times as long as the Semi-diameter of the Axis which 
the Silk turns upon, it is evident that our Senfibility 
of the Rod's Alteration will be increafed 60 times, 
&c. 
The Deal Rod is ftrongly nailed down at N, both 
in the firfi: and feeond Draught ; bur, in all other 
Parts, they have' free Liberty of Contra&ion or Dila- 
tation. 
Unlefs I am too much prejudiced in Favour of this 
Hygrometer, it far exceeds all that 1 ever faw ; and 
I may take upon me thus far to affert, that, by a&ing 
ten. 
