Calculations proving the comparative Economy of the Rocket Ammunition, both as to its Application in Bombardment and in the Field. So much misapprehension having been entertained with regard to the expense of the Rocket system, it is very important, for the true understanding of the weapon, to prove, that it is by far the cheapest mode of applying artillery ammunition, both in bombardment and in the field. To begin with the expense of making the 32-pounder Rocket Carcass, which has hitherto been principally used in bombardments, compared with the 10-inch Carcass, which conveys even less combustible matter. £. _s._ _d._ {Case 0 5 0 Cost of a 32-pounder {Cone 0 2 11 Rocket Carcass, complete {Stick 0 2 6 for firing in the present {Rocket composition 0 3 9 mode of manufacture. {Carcass ditto 0 2 3 {Labour, paint, &c. 0 5 6 ------------ £1 1 11 ------------ If the construction were more systematic, and elementary force used instead of manual labour, the expense of driving the Rocket might be reduced four-fifths, which would lower the amount to about 18_s._ each Rocket, complete; and if bamboo were substituted, which I am endeavouring to accomplish, for the stick, the whole expense of each 32-pounder Carcass Rocket would be about 16_s._ each. Now as the calculation of the expense of the Rocket includes that of the projectile force, which conveys it 3,000 yards; to equalize the comparison, to the cost of the spherical carcass must be added that of the charge of powder required to convey it the same distance. £. _s._ _d._ Cost of a 10-inch { Value of a 10-inch spherical Spherical Carcass, { carcass 0 15 7 with a proportionate { Ditto of charge of powder, 0 6 0 charge of powder, &c. { to range it 3,000 yards { Cartridge tube, &c. 0 1 0 ------------ £l 2 7 ------------