PYROTECHNY. 



aeatnefs, and ingenuity of contrivance. One piece of ma- 

 chinery I greatly admired ; a cheft. five feet (qiiare was 

 hoiftcd up by a pulley to the height of fifty or fixty feet 

 from the ground : the bottom was fo conllrufted as then 

 fuddenly to fall out, and make way for twenty or thirty 

 firings of lanterns enclofed in a box to dcfcend from it, 

 unfolding themfelves from one another by degrees, fo as at 

 lall to form a colle£tion of full 500, each having a light 

 of a beautifully coloured flame burning brightly within it. 

 This devolution and developement of lanterns were feveral 

 times repeated, and, at every time, exhibited a difference 

 of colour and figure. On each fide wns a correfpondcnce 

 of fnialler boxes, which opened in like manner as the others, 

 and let down an immenfe net-work of fire, with divifioiis 

 and compartments of various forms and dimenfions, round 

 and fquare, hexagons, oftagons, Sec. which fhone like the 

 brighteit. burnifiied copper, and flafhed like prifmatic light- 

 ning with every impulfe of the wind. The diverfity^of 

 colours with vv-hich the Chinefe have the fecret of clothing 

 fire feems one of the chief merits of their pyrotechny. 

 The whole concluded with a volcano, or general explofion 

 and difcharge of funs and flars, fquibs, crackers, rockets, 

 and granadoes, which involved the gardens tor above an 

 iiour in a cloud of intolerable fmoke." 



The apparatus ufed in making fire -works confifts of 

 folid wooden cylinders, called formers, for rolling the cafes 

 on ; fimilar cylinders, either of wood or metal, for ramming 

 dov/B the compofition ; moukls for holding the cafes while 

 filling ; a machine for contradting the cavity of the cafes ; 

 another for grinding the matt rials ; and a particular ap- 

 paratus for boring fome cafes after they are rilled. 



ConflruHion of the Cartridges for Rockets. - -A rocket is a 

 cartridge, or cafe made of ftiff paper, which, being filled 

 in part vt'ith gunpowder, faltpetre, and charcoal, r.fes of 

 itfelf into the air when fire is applied to it. There are 

 feveral kinds and fizes of rockets, but the three following 

 are the principal : -viz. 1. Small ones, the calibre cf which 

 is not larger than that of a bullet of a pound weig^'t. 

 2. Rockets, the calibre of which is equal to the fi/.e of 

 a ball of from one to three pounds weight. 3. Ljrge 

 rockets, equal to a ball of from three pounds to a hundred 

 weight. 



To give the cartridges the fame length and thickncf<!, 

 they are put into a hollow cylinder of metal, or ftiung wood. 

 This mould is not to be confounded with another piece of 

 wood, called the former or roller, around which is rolled the 

 thick paper employed to make the cartridge. The rule for 

 the fize of the mould and rolic-r is this : if the calibre of 

 the mould be divided into eight equal parts, the diameter 

 of the roller mufl. be equal to five of thefe parts ; of courfe 

 the vacuity between the roller and the interior furface of 

 the mould is equal to Jths of the calibre of the mould, 

 which will be exaftly filled by the cartridge. 



The fize of the mould is meafured by its calibre ; but 

 the length of the moulds for different rockets does not 

 always bear the fame proportion to the calibre, the length 

 being diminifhed as the cahbre is increafed. In fmall 

 rockets, the length of the mould ought to be fix times the 

 diameter of the calibre ; but in the larger fized rockets, It 

 need not be more than between four and five times the 

 calibre of the mould. 



Large ftiff paper of a peculiar kind is employed in 

 making cartridges, and hence it has obtained the name of 

 cartridge-paper. This paper is wrapped round the roller, 

 and then cemented by means of common patte. When the 

 cartridge is formed, the roller is drawn almoft out, by 

 turning it round, until it is diftant from the edge of the 

 5 



cartridge the length of its diameter. A piece of cord i* 

 then made to pafs twice round the cartridge at the ex- 

 tremity of the roller ; and into the vacuity left in the car- 

 tridge another roller is introduced, fo as to leave a fpace 

 between the two. By means of the cord, the cartridge 

 mull be pinched till there remains only an aperture capable 

 of admitting an inftrument called a piercer : then the 

 cord is removed, and its place is fupplied by a piece of 

 packthread. 



Befides the roller, a rod is employed to load the car- 

 tridge, which muft be fomcwhat fmaller than the roller, that 

 it may be eafily introduced into the cartridge. This rod 

 is pierced lengthwife to a fufficient depth to receive the 

 piercer, which mull enter into the mould, and unite with it 

 exaftly at the lower part. The piercer, which decreafes 

 in fize, is introduced into the cartridge through the part 

 wliere it has been choaked, and ferves to preferve a cavity 

 within it. 



After the cartridge is placed in the mould, the pre- 

 pared compofition is to be poured gradually in, and rammed 

 down with great accuracy. When the cartridge is about 

 half filled, feparate, with a bodkin, half of the folds of the 

 paper which remains, and having turned tiiem back on the 

 compofition, prefs them down, and pitrce three or four 

 holes in the folded paper, by means of a piercer, which 

 muft be made to penetrate to the compofition of the rocket. 

 Thefe holts ferve to form a communication between the 

 body of the rocket and the vacuity at the extremity of the 

 carriage, as it is called, or that part which has been left 

 empty. In fmall rockets this vacuity is filled with granu- 

 lated powder, and covered over, whicli ferves to let them off: 

 in thofe that are larger, the pot, containing ilars, fcrpents, 

 and running rockets, is adapted to it. 



It now remains to affix the rocket to its rod, which ig 

 thus done. When it has been conilrudted, in the way jult 

 defcribed, it is to be faftened to a rod of light fmooth 

 wood. Its length and weight mull be proportioned to the 

 fizc of the rocket ; that is, it ought to be as long as to 

 re-'ia'u in equdibrium with it, when iufpended on the finger, 

 or other fulcrum, within an inch, or an inch and a half 

 cf the neck. Betore it is fired, place it with the neck 

 downwards, and let it reft on two nails, in a diredlion per- 

 pendicular to the horizon : and to make it afcend to a 

 greater height, adapt to its fummit a pointed cap made of 

 ftiff paper, which will ferve to facilitate its paffage through 

 the air. To thefe rockets may be added feveral other 

 things, as a petard, which is a box of tin plate filled with 

 fine gunpowder, placed on the fummit. The petard is 

 placed on the compofition, at the end where it has been 

 filled, and the remaining paper of the cartridge is folded 

 down over it, to keep it firm. The petard produces its 

 effeft when the rocket is in the air, and the compofition is 

 confumed. A reprelentation of a rocket completely fitted 

 up is given in Plate Pyrotechny, Jig. 2. 



Stars, ferpents, &c. may be added to them, which is 

 done by ndjufting to the head of the rocket an empty pot 

 or cartridge, larger than the rocket, in order that it may 

 contain the things intended to render the exhibition the 

 more beautiiul. The following tables are neceffary to 

 thofe who would manufadlure rockets for themfelves. 

 The firft fhcws the fize of the calibre of the mould for 

 rockets of a pound weight and below ; and the fecdnd 

 points out the fize required for the calibre of moulds of 

 from lib. to 5c!bs. It muft be obferved, that a pound 

 rocket is that which is jutt capable of admitting a leaden 

 bullet of a pound weight, aed fo of the rell. 



TABI.S 



