The rockets which rise into the air

with a prodigious velocity, are among the most common, but not least interesting fire-works. When employed profusely they form those rich volleys of fire which are the crowning ornaments of a public fête. The cartridge is similar to that of the other jets, except in regard to its length, and the nece ity of pasting it strongly, and planing it well; but it is charged in a different manner. As the sky-rockets must fly off with rapidity, their composition should be such as to kindle instantly throughout their length, and extricate a vast volume of elastic fluids. To effect this purpose, a small cylindric space is left vacant round the axis; that is, the central line is tubular. The fire-workers call this space the soul of the rocket ( ame de la fusée ). On account of its somewhat conical form, hollow rods, adjustable to different sizes of broaches or skewers, are required in packing the charge; which must be done while the cartridge is sustained by its outside mould, or copper cylinder. The composition of sky-rockets is as follows :— | When the bore is | 3⁄4 of an inch; | 3⁄4 to 11⁄4; | 12⁄3; | | Nitre | 16 | | 16 | | 16 | | Charcoal | 7 | | 8 | | 9 | | Sulphur | 4 | | 4 | | 4 | | Brilliant Fire. | | | | | Nitre | 16 | | 16 | | 16 | | Charcoal | 6 | | 7 | | 8 | | Sulphur | 4 | | 4 | | 4 | | Fine steel filings | 3 | | 4 | | 5 | | Chinese Fire. | | | | | Nitre | 16 | | 16 | | 16 | | Charcoal | 4 | | 5 | | 6 | | Sulphur | 3 | | 3 | | 4 | | Fine borings of cast iron | 3 | coarser | 4 | mixed | 5 | The cartridge being charged as above described, the pot must be adjusted to it, with the garniture ; that is, the serpents, the crackers, the stars, the showers of fire, . The pot is a tube of pasteboard wider than the body of the rocket, and about one third of its length. After being strangled at the bottom like the mouth of a phial, it is attached to the end of the fusee by means of twine and paste. These are afterwards covered with paper. The garniture is introduced by the neck, and a paper plug is laid over it. The whole is inclosed within a tube of pasteboard terminating in a cone, which is firmly pasted to the pot. The quick-match is now finally inserted into the soul of the rocket. The rod attached to the end of the sky-rockets to direct their flight, is made of willow or any other light wood. M. Ruggier i replaced the rod by conical wings containing explosive materials, and thereby made them fly further and straighter. The garnitures of the sky-rocket pots are the following :— 1. Stars are small, round, or cubic solids, made with one of the following compositions, and soaked in spirits. White stars , nitre, 16; sulphur, 8; gunpowder, 3. Others more vivid consist of nitre, 16; sulphur, 7; gunpowder, 4. Stars for golden showers , nitre, 16; sulphur, 10; charcoal, 4; gunpowder, 16; lamp-black, 2. Others yellower are made with nitre, 16; sulphur, 8; charcoal, 2; lamp-black, 2; gunpowder, 8. The serpents are small fusees made with one or two playing cards; their bore being le than half an inch. The lardons are a little larger, and have three cards; the vetilles are smaller. Their composition is, nitre, 16; charcoal, not too fine, 2; gunpowder, 4; sulphur, 4; fine steel filings, 6. The petards are cartridges filled with gunpowder and strangled. The saxons are cartridges clayed at each end, charged with the brilliant turning fire, and perforated with one or two holes at the extremity of the same diameter. The cracker is a round or square box of pasteboard, filled with granulated gunpowder, and hooped all round with twine.