[ X 4 T ] 
Note , The pendulum being fo adjufted, as to make 
two vibrations in the time that the arm F G is in- 
tended to make one turn ; the pendulum being fet 
a vibrating, the experimenter pulls by the cord Z, 
with fufficient force to make each half revolution of 
the arm to correfpond with each vibration, as equal 
as poffible, during the number of vibrations that 
the experiment is intended to be continued. A 
little practice renders it eafy to give motion thereto 
with all the regularity that is neceffary. 
Specimen oj a Sett of Experiments. 
Radius of the fails 2 1 inches 
Length of ditto in the cloth — — 18 
Breadth of ditto j,6 
Angle at the extremity « 10 degrees 
(.Ditto at the greateft inclination — 25 
20 turns of the fails raifed the weight 11, 3 inches 
Velocity of the center of the fails, in the*} 
circumference of the great circle, in a VdF. o in. 
fecond — - — - J 
Continuance of the experiment 52 feconds. 
N*. 
Wt. in the fcale. 
Turns. 
Product. 
1 
O lb . 
108 — 
— O 
2 
6 
85 - 
5 IQ 
3 
6| 
8 r 
— 526 i 
4 
7 
78 - 
5+6 
5 
7 * 
n 
— maxim™ 
6 
8 
6 y - 
— 520 
7 
9 
- 0 — 
— 0 
* In all the following experiments the angle of the fails is ac- 
counted from the plain of their motion ; that is, when they ftand 
at right angles to the axis, their angle is denoted o°, this notation 
being agreeable to the language of practitioners, who call the angle 
fo denoted, the weather of the fail j which they denominate greater 
tar lefs, according to the quantity of this angle. 
N B . 
