The carcass-rockets are armed with strong iron conical heads, containing a composition as hard and solid as iron itself, and which, when once inflamed, cannot be extinguished. A 32 pounder carcass rocket will penetrate 9 feet in common ground. They have been known to pierce through several floors, and through the sides of houses. For field service, the 24, 18, 12, and 6 pounders are commonly used. The ranges of the eight-inch, seven-inch, and six-inch rockets, are from 2000 to 2500 yards, and the quantity of combustible matter, or bursting powder, from 25 lbs. to 50 lbs. These sized rockets are equally efficient for the destruction of bomb proofs, or the demolition of strong buildings. The largest rocket that has yet been constructed has not exceeded 300 weight. It is proposed, however, to make them from half a ton to a ton in weight.
The 42 and 32 pounders, which are used in bombardment, will convey from 7 lbs. to 10 lbs. of combustible matter each, and have a range of upwards of 3000 yards. The 24 pounder is equal to the propelling of the coehorn shell, or 12 pounder shot. It is, from the saving in weight, generally preferred to the 32 pounder. The eighteen-pounder, which is the first of the light nature of rockets, is armed with a nine pound shot or shell; the twelve-pounder, with a six do.; the nine-pounder, with a grenade; and the six-pounder, with a 3 lb. shot or shell.
The following table presents a general view of the ranges, elevations, and other particulars of several of the most useful descriptions of Congreve rockets.
From the preceding table, it will be seen, that the 32 pounder carcass rocket will range 3000 yards, with the same quantity of combustible matter as that contained in a ten-inch spherical case, and 2500 yards, with the same quantity as that of the thirteen-inch spherical carcass. The twelve pounder case-shot rocket, which is so portable that it may be used with the facility of musquetry, has a range nearly double that of field artillery, carrying as many bullets as the six pounder spherical case: add to which, that, from the nature of the combination of the rocket, these bullets are projected from it in any part of its track, with an increase of velocity, by which its operation becomes frequently more destructive at that point, where any different species of ammunition ceases to be effective. Of this description of rocket-case-shot, one hundred soldiers will carry into action, in any situation where musquetry can act, 300 rounds, and 10 frames for discharging them; from each of which, four rounds may be fired in a minute. Of the same description of case-shot, four horses will carry 72 rounds, and four frames; from which may be fired 16 rounds in a minute. The rockets used by cavalry are twelve pounders, armed with a 6 pounder shell or case shot; each horse carrying four of these rockets. To detail the arrangement of the rocket corps, the weight of ammunition carried by the troop horse, and other particulars, would require more space than we can conveniently appropriate to these subjects.
We may remark, however, that the heavier species of rockets, as the 32 pounder or 24 pounder, as also the 18 and 12 pounders, are sometimes carried in cars of a peculiar description; which not only convey the ammunition, but are contrived also to discharge each two rockets in a volley, from a double iron-plate trough. This trough is of the same length as the boxes for the sticks, and travels between them; but being moveable, may, when the car is unlimbered, be shifted into its fighting position, at any angle from the ground ranges, or point blank, up to 45°, without being detached from the carriage. The limbers are always in the rear. The rockets are fired with a port-fire and long stick.
When used by infantry, one man in ten, carries a frame of a very simple construction, standing on three legs like a theodolite, when spread. It is mounted at top with an open cradle, from which the rockets are discharged, either for ground ranges, or at any required elevation.
When they are used for bombardment, they are discharged from frames of a different, though simple, construction; and, in many cases, the frames are dispensed with, as they are thrown from a battery, erected for the purpose.
For the defence of a pass, or for covering the retreat of an army, the rockets are laid in batteries of 100 or 500 in a row, according to the extent of the ground to be protected. One man may fire the whole.
With regard to their use in the naval service, some additional remarks may be interesting.