Firework Making

1878 Scientific American  
its lead screw was too short by rto of a revolution in a length of 2 feet, the pitch of its thread being 6 to an inch. Now in 2 feet of the screw there would be 144 threads, and since Ito (the part of a revolution the thread was too short) x! (the pitch of the thread) = lido (which was called 6\)' the error amounted to ir; inch in 144 turns of the screw The construction of the device employed to cor rect this error is as follows: In Figs. 1 and 2, A represents the bearing of the feed screw of
more » ... the feed screw of the lathe, and B b a sleeve, a sliding fit upon A, prevented from revolving by the pin, h, while still having liberty to move endways. C represents a casing affording journal bear ing to B b, having a fixed gear wheel tJ,t its end, e ' , and an external thread upon a hub at that end. D is the flange of C to fasten the de vice to the shears of the latter, being held by screws. E represents an arm fast upon the collar of the feed screw, and carrying the pinion, F, the latter being in gear with the pinion, C', and also with G, which is a pinion containing two internal threads, one fitting to Ba t b, Fig. 2 , and the other fitting to C at e ' , Fig. 2, the former having a pitch of 27 threads to an inch, the latter a pitch of 25 to an inch. FIREWORK MAKINU. This art is, if not really a secret one, very littie known to the general public, owing to the danger attending the manu facture, which prevents casual visitors inquiring, and to the nature of the product, which offers no inducements to the analyst. In caIling special attention to pyrotechny as an art well worth cultivating, even although apparently an expensive luxury, we desire to laud the wondrous alsthetic effects of light and color, rather than the mere detonations calculated to impress the savage or the uncultured. 373 strips rolled ' around a �o ' oden mandrel. These cases are filled with" compositions" made 'of "meal powder" (that is, ungrained gunpowder) mixed with various ingredients. In some" pieces" there is required "force {' in others, color. In the rocket force is mos.t needed; in the Bengal light, color. Roman candles need force and color alter nately. For all, the cases need to be light and strong, and it is desirable to have the powder burn as long as possible. The meal powder is made of sulphur, niter, and charcoal. With this are mixed, according to the result desired, filings of cast and wrought iron, steel, copper, and zinc; dust of camphor, rosin, or lycopodium. To get the brightest red and white sparks, long iron filings free from rust are needed; for briHtant fire with radiations or coruscations, steel filings and cast iron borings. Green flames are given by copper; pale green, by verdigris; palm green, by blue vitriol (sulphate of copper) and by sal ammoniac. Blue is given by zinc; better blue, but with more smoke, by sulphu ret of antimony. Yellow comes from amber or rosin, or dry salt. Lampblack makes gun powder flame red, which an excess of niter tones down to pink. Camphor is used to give an intense white flame; also to give aro matic odors, as do benzoin and storax. Lyco podium gives magnificent rose-colored flames. Hundreds of formulas are given in Spon's " Workshop Recipes" and other works. The operation is as follows: The ordinary change wheels are connected to the feed screw, or lead screw, as it is sometimes termed, at J in the usual manner. The arm, E, be- DEVICE FOR CORRECTING A LEADING SCREW. The simplest element in pyrotechny is the small paper case called a "lance," used by hundreds in "set pieces." . Lance are quills or thin tubes (say 5 inches lo ng) of about M inch bore, and tightly rammed with a color composition. These are closely fixed perpen dicularly to frames of desired outl ine, and their outer ends connected by a quick match ing fast to the feed screw will revolve with it, and cause It is a matter of great regret that the results of the pyro· the pinion, F, to revolve around the stationary gear wheel, technist's art are so evanescent, not even ephemeral, but al O. F also gears with G. Now F is of 12 diametrical pitch most instantly vanishing. The stately rocket and its comet and contains 26 teeth, C' is of 12 diametrical pitch and conlike tail of soft fire, the fiercely hissing gerb, the detonating tains 37 teeth, and G is of 12 diametrical pitch and contains bomb, and the fountains and myriad devices delighting with 36 teeth. It follows that the pinion, F, while moving around swift surprises in coruscation, steady glow, flashing, gleam the fixed gear, C', will revolve the pinion, G (which acts as ing, and waning-all minister to our sense of the beautiful, a nut), to an amount depending upon the difference in the and are well calculated to arouse and to maintain enthusiasm number of its teeth and those of fixed gear, C' (in this case . as in the cause in which they are offered in honor. 36 is to 37), and upon the difference in the pitches of the two I It is our purpose to approach within the precincts, and threads, so that at each revolution G will move the feed screw analyze the modes by which all these effects are produced.
doi:10.1038/scientificamerican06151878-373a fatcat:dolb66dgwjerzjqgnsmvulmffu