NEW EXPERIMENTS

TRACT 34.

148

differences of 50 feet, and the column of corresponding re-sistances are reduced by a due proportion, to uniformity andregularity, which appears by the differences in the last co-lumn of that table. That is, the numbers in the 2d columnof table 2, show the true resistances sustained by a ball of3-55 inches diameter, when moving through the air with thevelocities in the preceding column, viz, a resistance of 1840oz, or 115lb, when moving with a velocity of near 1200 feetper second, &c. &c.

The curve constructed from these velocities and resistances,is the curve ai, plate 2, being similar to those before con-structed.

Obsei'vations on the preceding Experiments, in the year 1791,with the Ballistic Pendulum.

194. The experiments of this year were performed withthree 6-pounder guns, all of equal diameter in the bore, butof different lengths and weights.

The few 6-pound balls that were fired against the ballisticpendulum, towards the conclusion of the last year’s experi-ments, gave reason to hope that the pendulum might bearthat weight of balls; and, by enlarging the apparatus, thatit might even bear the shock of balls of a still larger size;the experiments of this year have therefore been prosecutedwith balls rather higher than those of 6lb weight.

For this purpose, some pendulum blocks of wood wereprepared, of a larger dimension than formerly, that theymight not be perforated quite through by these heavy balls ;with a proportionably strong apparatus of iron to bind themtogether, and to suspend them ; the whole amounting to al-most a ton weight.

The three 6-pounders with which these experiments wereperformed, were two short guns and a long one, the for-mer of equal lengths, but differing in their weights, asfollows.