TRACT 34;
IN GUNNERY.
331
plugs, the whole ball which came out behind, as well as thebroken pieces of the wood and balls which flew out in thelatter rounds, being collected and weighed with it; which isabout 154 lb less than it ought to be; so that about 15-tlbhas been lost by evaporation in the space of 30 hours, orabout half a pound an hour.
At n® 5 4, 8, 10 the tape of the pendulum entangled andbroke, which rendered those vibrations doubtful, as markedD. Some other rounds are marked doubtful, from someother cause, perhaps the badness of the wood in the pen-dulum, which split very much ; from which circumstancepart of the force of the ball might be lost by the lateralpressure.
The plugs weighed 14 oz to 15 inches.
The value of i, or the mean point struck, 89'5 inches.
The penetration at the 1st and 7th rounds, which weremade in fresh parts of the wood, were from 19 to 20 inches;so that the fore part of the ball penetrated about 21-|- inchesin this softwood.
Mean recoil and velocity by the pendulum.
Powder
Recoil
Veloc.
8
-
-
26*7 -
- 1569
10
-
-
30-0 -
- 1608
12
-
-
32-4 -
- 1615
14
-
-
33'4d-
- 1517 D
16
-
-
36-8 b -
- 1664D
18
-
-
37-1
20
-
-
39-8
22
-
-
41-5
24
-
-
42-6
28
-
-
44-2
32
•
52-8 D
But these mediums are not much to be depended on, asthe velocities are all very irregular. It is, in particular,highly probable that the velocity here found for 14 oz ofpowder is too small, and that for 16oz too great.