TRACT 34.

IN GUNNERY.

371

At the 7th and 15th rounds the balls struck both in firmand solid wood, when their penetrations, to the hinder partof the ball, measured 10*- and 11 inches; so that the forepart penetrated 12£ inches in the first case, and 13 inches inthe latter.

Gun 1

Mean length of the charge - 11‘4Mean recoil with ball - - 36-35

Ditto without - - - - 23 - 63

Difference, or c = - - - 12 - 72

Hence velocity by the recoil 1399Mean ditto by the pendulum 1419Di fl’erence, the recoil less - 20

Or nearly the part ' - - - ^

Gun 211*3

40-03 omitting n®1426-4513-5814971676179*

58. N. B. In this day’s experiments, and those that lol-low, as long as the same block of wood is used, the theoremsfor correcting the place of the centre of gravity, and thenumber of oscillations per minute, as laid down at Art. 44,will be a little altered, when the weight of the pendulum isvaried at the centre of the block. The reason of which is,that now the distance to the centre is 88 7, which beforewas only 88-3. And by using 88-7 for 88"3 in the theoremsin that article, those theorems will become

G = 88 - 7 — ' 1 — for the new value of g, and

P

314

n = 39*646 -\ -— for the new value of ri.

p — 93

Had i been = 89'3, the new value of g and n would

have been

7920 ,

G = 89-3-, and

N = 39-51 +^lhi?

And these last are the proper theorems for this day’s expe-riments, the mean distance of the points struck being nearly

89-3'.