360

NEW EXPERIMENTS

TEACT 34.

The Pendulum . Its weight at first round 664-7To the tape - - - 117-8

i

It had remained hanging since the last day’s experiments,with all the balls and plugs in it, which increased its weightby 10 lb, except an allowance for evaporation, and increasedthe distance of the centre of gravity by little more than -^-thof an inch It vibrated with great freedom ; for it had thisday been made to turn very freely on its axis, by placingthe upright pins, which confine it sideways, so as not quiteto touch the axis, like those of the gun yesterday ; and theeffect was very greatindeed, for itappearedas if it would havevibrated for a great length of time ; whereas on the formerdays it stopped motion in about 1 minute, or at least afterthat the arcs soon became too small to be counted,—By thisday’s firing the pendulum seemed not to be much injured,the back part not appearing to be altered, and the fore part9 nly a little swelled out, the piece of wood which had beenfitted in there, starting a little forward, and bulging out thefacing of lead.

Of the plugs every 10 inches in length weighed 11 oz.

4oz

8 oz

The mean recoil of gun with ball

18-23 -

- 28 45

without

6 23 -

- 13-75

the difference or c —

11-98 -

- 14 70

Hence the velocity by the recoil is

1321 -

- 1620

Mean ditto by the pendulum - -

1353 -

- 1766

Which exceeds that by recoil by

32 -

- 146

Or the

42d -

- 12 th part.

This appears to be a good set, being very uniform, ex-cept the 13th round, which has been omitted, as evidentlydefective in the arc described both by the gun and pen-dulum, from some undiscovered and unaccountable cause.