12

NEW EXPERIMENTS

TRACT 34.

• there will remain only 6971b, which the pendulum ought toweigh, and which is 9lb less than it is actually found toweigh. I cannot imagine any cause to which this differenceof weight may be attributed, as it is contrary to the effectheretofore experienced, the pendulum having always beenfound to lose in weight by hanging up ; unless it arise fromthe moisture imbibed by the block in the 17 days it was up,and during all or the most part of which time it was veryrainy weather, and the pendulum hung uncovered. Nowthe probability of this will be heightened by considering thatthe block had lain by all the preceding winter, and till aftermidsummer this year, under cover, in the carpenter’s shop,a circumstance which would make it very dry, and so renderit apt to imbibe moisture from the continually foggy atmo-sphere and rain, which have taken place ever since it wasexposed. This increase of weight then, being 9lb in the 17days, or nearly halfa pound per day,I havethought it safest todivide equally among all the days, by adding half a poundfor each day it hung up, from the beginning of this year tothe end of this day’s experiments.

The Object of this course was again to search out themaximum of the gun’s charge; but it is not a good set ofexperiments, the velocities being not regular, perhaps ow'ingto the bad state of the pendulum, which was very much shat-tered. However it sufficiently appears that there was but lit-tle difference among the velocities due to 8, 10, 12, and 14ounces of pow'der.

Weight of Powder 6 oz

Mean height of charge 4 - 4

Mean recoil of gun - 201

Velocities by pendu-lum -

8 oz

10 oz

12 oz

14 oz

5-7

7-0

8-1

9-5

237

264

291

318

1499

1561

1566

15651

1505

1452

1546

1508 [•

1421

1466

1448

1510 \

1319

1388

1398

Mean ditto

1368

1493

1528