OF PROJECTILES

2- That with the medium charges they are verynearly as follows ;

Nature of Guns.

Initial Velocities,

Feet.

Fn.

V2

|6

8

4

135 °

1416

*449

1467

3. That with the less charges (143) they will beabout ^ less than with the medium charge; for in-stance, a shot from a 32 pr. charged with 7^Ibs. of pow-der, will be impelled with an initial velocity of about1180 feet, and a Ihot from an 8 pr. with 2§lbs. ofpowder, with an initial velocity of about 1269 feet.

4. With the least charges (143, No. 3) the ini-tial velocities will be about T \ less than those with themedium charge ; for instance, a shot from an 8 pr.charged with ilb. 10 oz. of powder, will be impelledwith an initial velocity of iobj feet; and a shot froma 16 pr. with 2f'bs. of powder, with an initial velocityof 1028 feet. It should be recollected, that with smallcharges, the least difference in the mode of loading thethe gun, makes a great alteration in the initial velocities,while with large charges its effects would be scarcelyperceptible. The surest mode of keeping all circum-stances as nearly equal as possible, is always to ram thewads well.

151. In experiments with three or four guns of thefame calibre, but of different lengths, loaded as above (150,No- 2); the following rule will furnish an approximationsufficiently exact to draw from it conclusions applicable topractice. (PI. 5, Fig. 15,) E B F represents the bore of agun of any calibre ; the medium charge of powder D andthe wad 8 are so placed, that the shot A is distant from B

2 A F

three diameters of the bore FE: make FL—-and

3

from the point C as centre, with the radius C A, describethe arch A K P R, representing the scale of initial velocities,by lines drawn perpendicularly from AF to the arch. Todetermine the initial velocity of a shot fired, for instance,front a long gun B L (66) } loaded in the same manner (1 ,