142
NEW EXPERIMENTS
TRACT 34.
So that nothing has been lost by evaporation, owing pro-bably to the pendulum having been kept closely coveredup with the painted cloth.
186. Oct. 10, 1791.
Barometer 29 27; Thermometer 57.
The pendulum having been again repaired, and its facecovered with a new sheet of lead, the following rounds u f erefired from the long 6-pounder, mounted as before, at 285feet distance, with balls weighing each 6lb 1-foz, and diam.S’55. The pendulum weighed 186lib, and the medium ofits centre of gravity measured 77 inches, which I suspect iserroneous, as the pendulum is nearly the same weight as be-fore, when that centre was only at 76-6 ; I have thereforeassumed the medium 76 8 to begin with It vibrated 40 perminute.
Eprouvette.
2 oz 42^ chord.
2 42 *
N°
Pow-
der
Recoil
gun
Vibr.
pend
Point
struck
Plugs
wt
Values of
Velocity ofthe ball
V
e
n
oz
inches
c
inches
oz
lb
inches
feet
1
48
49
374
85-8
16
1861
76-8
40
1571d
2
48
63
432
92-9
15
1867
8
1674d
3
48
54
416
91-5
14
1864
8
1641
4
32
36
329
79-5
13
1869
8
1496
5
32
36
358
84-6
12
1845
8
1513d
6
24
277
74-7
1852
7
1329d
N° 1 is doubtful.—At N° 2 the ball came out at the sideof the pendulum, and struck an iron band, which it cracked,and then rebounded, also some splinters of wood flew out,both making the recoil too great.—At N® 5 some more splin-ters, and a piece of iron band burst off by the elasticity ofthe wood, weight 29lb, when the pendulum began its mo-tion, which again made the vibration too great.—N° 6 alsoburst another band, and ruined the pendulum. So that thereare only two or three indifferently good shots.