350 NEW EXPERIMENTS TRACT 34.

439

290

90-30

89-06

729 :

290 :

: 1 -24 :

>

0-49

90-30

- - TD

- - At

89-81

44-25

- - AD

- - A G

729

188

45-56

- - GD

917 :

729 :

: 45-56 :

36-22

44-25

- - G E

- - A G

80-47

- - A E

where d is the centre of gravity of the bodies at the pointsc and t, or of the gun and leads ; and e the centre of gra-vity of the two bodies placed at the points g and d, or ofall the three bodies at the points o, c, t ; that is, e is thecompound centre of gravity for both gun, iron, and leads,in one mass. And the same operation is to be repeated forthe other guns.

43. It may here be also remarked, that the mean num-ber of vibrations per minute, for every gun, weighing in all917 lb, taken among the actual vibrations of each day, isfor

n* 1 n* 2 n° 3 n° 4

40-1 40‘0 39-9 39-8

•which number must be used as the true value of n, in theformula for the velocity of the ball by means of the recoilof the gun. The number of the gun’s vibrations was com-monly tried every day, and they were found to vary butlittle, and among them all the numbers above-mentioned,are the arithmetical mediums.

44. Moreover, the mean numbers for the pendulum,among all the daily measurements of its weight, centre ofgravity, and oscillations per minute, are thus :

weight g > n

660 lb 77-3 40-2

Of the great number of these measures that were taken,the variations among them were sometimes in excess

A