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NEW EXPERIMENTS

TRACT 84.

fresh part of the wood, both to obtain the force of the blowthe more accurately, and to take the penetration of theball in the solid wood, which we did every time by pushingin a wire to touch the hinder part of the ball : these penetra-tions are various, according as the part struck was more orless compact, and they are rather larger than was expected,the medium of all being 18,%, though the block of elm, asthe carpenters assured us, was sound, dry, and well-sea-soned wood. The penetrations are set down in the lastcolumn, and are for the fore part of the balls, the diameterhaving been always added to the length of the wire.

The Powder was not of the same parcel as the twoformer years ; but it was from the same maker, and madeas nearly similar to the former as might be. The chargeswere gently set home, and all circumstances made alike.The mean length of the charge of 8 oz was 4-84.

The Pendulum had been kept close covered with apainted canvas cloth since the first day that it was weighedand measured, to preserve it from the weather. The plugsweighed 9 ounces to every 11 inches in length ; the wholeweight of all the plugs, together with that of the 8 balls,make up 13 lb, wanting only an ounce and a half; andwhen the pendulum was taken down and weighed this after-noon, its weight was found to be 808 lb, which is just 13 lbmore than its weight at first. So that it has neither lostw-eight by evaporation, nor gained by imbibing moisture:owing, probably, to the circumstance of being covered bythe painted canvas. All the apparatus was in good order,and the experiments all very accurately made.

At the beginning of these experiments, the values ofp, g, n, being p = 795, g = 78-^-, n = 40-07; if these valuesbe substituted in the two theorems

° = * + h#’

n = n —

bin(inn — 140850 )

281700 pg + bi{inn + 140850 )*

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