[ 68 7 ] 
may be compared uniformly in different Experi- 
ments, the, Bottom of the Rod muft always be im ’ 
merfed to the fame Height in the Matter to be exa- 
mined j and therefore 1 make a Mark, a fmall Fur- 
row f quite round the Rod, i~ Inch from the'Bot- 
tom B. For the deeper the Rod is immerfed into 
any Matter, it will be lengthen’d the more by the 
fame Degree of Heat. 
FF, the Lever, which turns upon an Axis G. 
At F is fattened a String, which, patting twice round 
the fmall Pulley //, has a Weight I hanging to the 
other End of ir, of about half a Pound, being enough 
to keep the String always ftretch'd. At the other 
End E of the Lever is hung another Weight L 7 
which muft be heavy enough not only to counter- 
balance the longer Arm GF, but prefs down upon the 
Point A with a Weight fufficient to keep its fteady. 
MNO , is the back Part of the Plate, like the 
Dial-Plate of a Clock made of Brafs. See the Front 
of it at Fig. 3. 
The Pulley //turns upon an Axis C in Fig. 3. 
which goes thro* the Plate, and on the other Side 
or Front of the Dial-Plate carries a Hand or Index 
AB in Fig. 3. 
N. B. G being the Fulcrum of the Lever, the 
Diftance GA being very fmall, and the Diftance 
GF being very great, the fmalleft Motion at A 
will produce a very great one at F, and therefore 
the Index will turn very fenfibly upon the Plate. 
The Proportions of the Rod and Lever are dif- 
crctionary,- my Rods both of Steel and Brafs are 3 
Feet long in one folid Piece, but they have each a 
Point or Cone of Steel 1 Inch high, that fcrews 
U u u u upon 
