Dimensions of Rockets.

TABLE I.

	Length of the
Weight of	moulds without	Interior diameter	Heights of the
Rockets.	their feet.	of the moulds.	nipples.
6 lbs.	34.7 inches.	3.5 inches.	1.5 inches.
4 do.	31.6 do.	2.9 do.	1.4 do.
2 do.	13.3 do.	2.1 do.	1.0 do.
1 do.	12.2 do.	1.7 do.	0.85 do.
8 ozs.	10.12 do.	1.3 do.	0.6 do.
4 do.	7.75 do.	1.12 do.	0.5 do.
2 do.	6.2 do.	0.9 do.	0.45 do.
1 do.	4.9 do.	0.7 do.	0.33 do.
½ do.	3.7 do.	0.55 do.	0.25 do.
6 drs.	3.5 do.	0.5 do.	0.22 do.
4 do.	2.2 do.	0.3 do.	0.2 do.

By this table we find that a six-pound Rocket rammed solid, must be thirty-four inches, seven-tenths in length; its external diameter three inches five-tenths or three and half inches, and the height of the nipple one inch and a-half. The diameter of the nipple in this and all other cases must be equal to that of the former, and in regard to its height I have never found it to answer better than when the cavity which it formed at the mouth of the Rocket was hemispherical, or equal in height to half its diameter.

We shall now, by the following table, shew the method of finding the calibre of Rockets according to their weight, which is computed by the principles already given; that is, a pound Rocket is such that its aperture will just admit a bullet of a pound weight, and so of the rest.