Smaller vessels, such as gun brigs, schooners, and cutters, may be fitted to fire Rockets by frames, similar to the boat frames, described in Plate 11, from their spar deck, and either over the broadside or the stern; their frames being arranged to travel up and down, on a small upright spar or boat’s mast, fixed perpendicularly to the outside of the bulwark of the vessel. As a temporary expedient, or in small vessels, this mode answers very well; but it has the objection of not carrying the sparks so far from the rigging, as when fired from below: it interferes also with the fighting the guns at the same time, and can therefore only be applied exclusively in the case of bombardment. All the gun brigs, however, on the Boulogne station, during Commodore OWEN’s command there, were fitted in this manner, some with two and some with three frames on a broadside. [Illustration: _Plate 12_  Fig. 1  Fig. 2  Fig. 3  Fig. 4] ROCKET AMMUNITION. Plate 13 represents all the different natures of Rocket Ammunition which have hitherto been made, from the eight-inch carcass or explosion Rocket, weighing nearly three hundred weight, to the six-pounder shell Rocket, and shews the comparative dimensions of the whole. This Ammunition may be divided into three parts--the heavy, medium, and light natures. The _heavy natures_ are those denominated by the number of inches in their diameter; the _medium_ from the 42-pounder to the 24-pounder inclusive; and the _light natures_ from the 18-pounder to the 6-pounder inclusive. The ranges of the eight-inch, seven-inch, and six-inch Rockets, are from 2,000 to 2,500 yards; and the quantities of combustible matter, or bursting powder, from 25lbs. and upwards to 50lbs. Their sticks are divided into four parts, secured with ferules, and carried in the angles of the packing case, containing the Rocket, one Rocket in each case, so that notwithstanding the length of the stick, the whole of this heavy part of the system possesses, in proportion, the same facility as the medium and light parts. These Rockets are fired from bombarding frames, similar to those of the 42 and 32-pounder carcasses; or they may be fired from a slope of earth in the same way. They may also be fired along the ground, as explained in Plate 9, for the purposes of explosion.