If σ denotes the density of the metal, and if the shell has a cavity homothetic with the external ellipsoidal shape, a fraction f of the linear scale; then the volume of a round shot being 1⁄6 π d3, and 1⁄6 π d3 x of a shot x calibres long
W = 1⁄6 πd3 x (i − ƒ3) σ,
(20)
| Wk12 = 1⁄6 πd3 x | d2 | (1 − ƒ5) σ, |
| 10 |
(21)
| Wk22 = 1⁄6 πd3 x | l2 + d2 | (1 − ƒ5) σ. |
| 20 |
(22)
If ρ denotes the density of the air or medium
W′ = 1⁄6 πd3 xρ,
(23)