[ 688 ] 
upon the Top at A . The Lever has 4 Inches from 
E to A , if Inch from A to G, and 12 Inches from 
G to Fs the Diftance of G above c is T~ Inch, the 
brafs Pulley H is ~ Inch Diameter ; all the other 
Parts of the Machine are of Oak. The main Sup- 
port or Pillar w ?6Hs 1 Inch fquare, 2~ Feet high, 
and at Bottom is let thro’ a Groove at ^ made in a 
great heavy Block or Pedeftal of Wood RS. In 
' this Groove the Pillar may be raifed higher or lower, 
in order to adjuft the Height of the Pillar to the Si- 
tuation, which the Bottom of the Rod may re 
quire in different Experiments 5 and it is to be fixed 
in that Place by a Screw at T, which goes thro’ the 
Front of the Block, and preffes againft the Bottom 
of the Pillar. 
Fig. 3 . reprefents th z c Dial- c Plate> or Front of the 
Plate mark’d MNO : In Fig • 2. it is a Plate of 
Brafs, with ftrong Paper glued upon it, and may 
be of what Size you pleafe 5 mine is 11 Inches 
over. 
AB is the Hand or Index > which flips on very 
ftiff upon the Axis C, that carries the Pulley H in 
Fig. 2. The outer Circle is to be left wide enough 
to contain the chemical Characters or Marks which 
are to be made upon ir, the Arch 2 XE contains the 
Divifions of Fahrenheit’s Mercurial Thermometer, 
the Arc FG thofe of Reaumur , or the Spirit of 
Wine Thermometer. 
In order to adjuft this Tnftrument for Ufe I place 
the Bottom of the Rod B in Fig . 2. immerfed up 
to the Mark p in cold River or Rain Water, in a 
Vefiel proper to be fet over the Firej and when it 
has 
