recoil; or even by stopping the recoil entirely, no sensible change is produced in the Velocity of the ball.

8. The Velocity increases with the Charge to a certain point peculiar to each Gun; but by farther increasing the Charge, the Velocity gradually diminishes; yet the recoil is always increased by an increase of Charge. Vide 3

9. The Velocities of Balls fired with equal Charges increase to a certain point, when the Gun is longer, in a proportion which is nearly the middle ratio between the square and cube roots of the length of the bore.

10.-When Shot of different Weights are fired with the same Charges of Powder, the Velocities communicated to them are nearly in the inverse ratio of the square roots of their Weights. Therefore Shot which are of different weights, and impelled by the firing of different charges of powder, acquire velocities which are directly as the square roots of the charges of powder, and inversely as the square roots of the weight of the shot. By making use of shot of a heavier metal than iron (lead for instance) the momentum of the shot, discharged with the same charge of powder, would be increased in the ratio of the square root of the shot's weight, which would both augment the force of the blow with which it would strike, and also the extent of the range. Compound shot, or shells filled with lead, fired with charges increased th will increase the power of Range considerably.

11. With common Shells at 45° Elevation, the Time of Flight is nearly equal to the square root of the range in feet divided by 4; or more nearly, equal to the square root of the quotient of the range in feet divided by 16.

12.-The Range at 45° Elevation, is nearly equal to the square of the time of flight in seconds multiplied by 16,1⁄2 feet. The range at 15° will be about half that at 45°.

13. Upon Inclined Planes at any Elevation, there are always two elevations with which any range may be obtained.

The Elevation, which gives the Greatest Range on a given Ascent, is equal to half the sum of 90° added to the

ascent.

The Elevations, which give Equal Ranges on a given Ascent, are the compleme nts of each other added to the

ascent.

The Elevation, which gives the Greatest Range on a Descent, is equal to half the complement of the descent.

14-The Depths penetrated by Balls of the same size into Wood, with different Velocities, or Charges, are nearly as the squares of the velocities. Balls of different sizes will penetrate to depths proportionate to their diameters: therefore a greater ball will not only make a larger hole, but will also penetrate farther than a small one with the same velocity.

15.-By Experiments at a mean Range, it has been ascertained that in common Earth, dug up and well rammed; a Musket Ball buries itself nearly ....... a6 Pr. from 31 ft. to 4ft. 9 Pr. from 6 ft. to

11⁄2 ft.

7 ft.

12 Pr. from 8 ft. to 10 ft. 18 & 24 Prs. from 11 ft. to 13 ft.

F F

NAVAL GUNNERY.

In firing into masses of Timber, or any solid substance, that Velocity which can but just penetrate, will occasion the greatest shake, and tear off the greatest number of, and largest splinters: consequently in close Actions, Shot discharged with the full quantity of powder, tear off fewer splinters than Balls fired from the same nature of Guns with reduced charges.

In Naval Actions, Shot intended to take effect upon the hull of an Enemy, should rather be discharged with a falling than with a rising side; but such pieces, as may be appointed specially to act against the masts and rigging, should be fired, on the contrary, with the rising motion, the aim being taken low.

In all close Actions, the great object should be to strike as often as possible the Enemy's hull. One or two 24lb. Shot taking effect below the water line, and perhaps perforating both sides of a small Vessel, will in general either force her to surrender, or send her to the bottom; and such an injury is much more likely to be occasioned by firing with a falling than with a rising side.

To estimate the Distance between Vessels.

Measure with a Sextant, or Quadrant, the angular height of the Enemy's mast, and by referring to Table B, the corresponding Distance may be taken out.

In Table A, the Height of the Masts to the head of the main top gallant rigging, and likewise to the main top mast cross trees above the surface of the water at low water mark, are given for every Rate, and Class of Vessel.

The Distances in English yards and feet, corresponding to the angles subtended by the Masts, are given in the first column of Table B.

Thus, if an Enemy's Vessel is ascertained to be a 1st Class, or 44 gun Frigate, and that the measured angle subtended by the main mast to the top mast cross trees is 52', the corresponding Distance is 746 yards.

Table B may also be applied to the important purpose of determining Distances, making use of the Ship's own mast as the given height, or side of the triangle, by marking upon it any of the heights expressed in the Table, and placing an Observer there when required to measure the angle A B C (Vide Fig.) formed by the Mast when most perpendicular, and the line of sight B C.

B

A

The Tangent Practice Tables C and D will frequently be found useful in pointing Ordnance, when the Distance is known; for by referring to that distance in the 1st column of the Table belonging to the corresponding nature of Gun, the part, that should be aimed at, will be ascertained.

or 2d do.

Line of Battle Ships, of Guns,

12 9 12

9

12

9

12

6

Cap of the mizen top mast