PYROTECHNY.

447

Lights of another kind. —Saltpetre, 31b. brimstone, lib. meal-powder, lib. antimony, 10 and a half oz. All these must be mixedwith the oil of spike.

A Red Fire. —Meal-powder, 31b. charcoal, 12oz. and saw-dust,Soz.

A Common Fire. —Saltpetre, 31b. charcoal, 10 oz. and brim-stone, 2oz.

To make an artificial Earthquake.—M\\ sulphur, 41b. andsteel-dust, 41b. to a paste with water, and then bury it in theground, and in a few hours the earth will burst open in severalplaces.

Of Moulds, Cases, Mixture, Instruments , &c.

Rocket-moulds. As the performance of rockets depends muchon their moulds, it is requisite to give a definition of them, and theirproportions. They are made and proportioned by the diameterof their orifice, which is divided into equal parts. Hammers musthave a collar of brass at the bottom, to keep the wood from spread-ing or splitting, and the same proportion must be given to allmoulds, from one ounce to six pounds. As to the handles of therammers, if their diameter is equal to the bore of the mould, andtwo diameters long, it will be a very good proportion; but theshorter you can use them the better ; for the longer the drift, theless will be the pressure on the composition by the blow given withthe mallet.

Dimensions for Rocket-moulds, if the Rockf.ts areRammed solid.

Weight

Length of the

Interior dia-

Height

of

moulds with-

meter of the

of the

rockets.

out their feet.

moulds.

nipples.

lbs. oz.

Inches.

Inches.

Inches.

6 0

34,7

3,5

1,5

4 0

38,6

2,9

1,4

2 0

13,3:1

2,1

1,0

1 0

12,25

1,7

0,85

0 8

10,125

1,333, &c.

0,6

0 4

7,75

1,125

0,5

0 2

(i,2

0,9

0,45

0 1

4,9

0,7

0,35

0 i

3,9

' 0,55

0,25

6 drams

3,5

0,5

0,225

4 dram.

2,2

0,3

0,2

Moulds for H'hed-cases or Serpents .—This soil of moulds aremade ot any length or diameter, accord ng as the cases are re-quired ; but the diameter of the rollers must be equal to half thebore, and the rammers made quite solid.

To roll Rocket and other Casus. —Skyrocket-cases are to bemade 6J of their exterior diameter long; and all other cases thatare to be filled in moulds must be as long as the moulds, withinhalf its interior diameter. Rocket-cases, from the smallest to 4 or61b. are gem-rally made of the strongest sort of cartridge papei,and rolled dry; but the large sort are made of pasted pasteboard.As it is very difficult to roll the ends of the cases quite even, thebest way will be to keep a pattern of the paper for the differentSorts of cases; which pattern should be somewhat longer than thecase it is designed for, and on it marked the number of sheets re-quired, which will prevent any paper being cut to waste. Havingcut your papers of a proper size, and (he last sheet for each case"’itb a slope at one end, so that when the cases are rolled it mayform a spiral line round the outside, and that this slope may alwaysbe the same, let the pattern be so cut for a guide. Before you be-gin to roll, fold down one end of the first sheet, so far that the foldVdll go two or three times round the former ; then, on the doubleedge; lay the former with its handle off the table ; and when youhave rolled on the paper within two or three turns, lay the nextsheet on that part which is loose, and roll it all on. Having thusdone, you must have a smooth board, about 20 inches long, andequal in breadth to the length, of the case. In the middle of this

board must be a handle placed lengthwise. Under this board layyour case, and let one end of the board lie on the table; thenpress hard on it, and push it forwards, which will roll thepaper very tight: do this three or four times before you roll onany more paper. This must be repeated every other sheet ofpaper, till the case is thick enough; but if the rolling-board isdrawn backwards, it will loosen the paper: you are to observewlien you roll on the last sheet, that the point of the slope may beplaced at the small end of the roller. When thfc cases are hard tochoak, let each sheet of paper (except the first and last, in thatpart where the neck is formed,) be a little moistened with water ;immediately after you have struck the concave stroke, bind theneck of the case round with small twine, which inust not be tied ina knot, but fastened with two or three bitches. Having (buspinched and tied the case so as not to give way, put it into themould without its foot, and with a mallet drive the former hard onthe end-piece, which will force the neck close and smooth. Thisdone, cut the case to its proper length, allowing from the neck tothe edge of the mouth half a diameter, which is equal to the heightof the nipple; then take out the former, and drive the case overthe piercer with the long rammer, and the vent will be of a propersize. Wheel cases must be driven on a nipple with a point toclose the nock, and make the vent of the size required ; which, inmost cases is generally one-quarter of their interior diameter. As itis very often difficult, when the cases are rolled, to draw the rollerout, y ou may make a hole through the handle, and pul in it a smalliron-pin, by which you may easily turn the former round and pullit out.

To make Tourhillon-cases ■—This sort of cases are generallymade about eight diameters long; but if very large, seven will besufficient. Tourbillons will answer very well from 4oz. to 21b. butwhen larger there is no certainty. The cases are best rolled wetwith paste, and the last sheet must have a straight edge, so that thecase may be all of a thickness. When you have rolled your casesafter the manner of wheel-cases, pinch them at one end quite close ;then with the rammer drive the ends down fiat, and afterwards ramin about one-third of a diameter of dried clay. The diameterof the former for. these cases must be the same as for sky-rockets.

Balloon-eases, or Paper shells.— First, you must have an ovalformer turned of smooth wood; then paste a quantity of brown orcartridge-paper, and let it lie till the paste has quite soakedthrough : this done, rub the former with soap or grease, to preventthe paper from sticking to it; then lay the paper on in small slips,till you have made it one-third of the thickness of, the shell in-fended. Having thus done, set it to dry, and when dry, cut itround tlie middle, and the two'halves will easily come off; butobserve, when you cut to leave about one inch not cut, whichwill make the halves join much better than if quite separated.When you have some ready to join, place the halves even together,paste a slip of paper round the opening to hold them together, andlet that dry; then lay on paper all over as before, every whereequal, excepting that end which goes downwards in the mortar, .which may be a little thicker than the rest; for that part whichreceives the blow from the powder in the chamber of the mortarconsequently requires the greatest strength. When the shell isthoroughly "dry, burn a round vent at top, with an iron largeenough for the fuze: this method will do for balloons from 4 inches2-5ths, to 8 inches diameter ; but if they are larger, or required tobe thrown a great height, let the first shell be turned of elm, insteadof being made of paper. I 1 or a balloon of 4 inches 2 oths, let the ■former be 3 inches 1 -Sth diameter, and 5| inches long. For a bal-loon of 5-i inches, the diameter, of the former must'be 4 inches, andS inches long. I* or a balloon of 8 inches, let tire diameter of theformer be 5 inches and 13-1 fifths, and 11 inches 7-8ths long. Fora 10-inch balloon, let the former he 7 inches 3-l6lhs diameter, and14J inches long. The thickness of a shell for a balloon of fourinches 2-5ths must he half an inch. Fora balloon of 5-| inches,let the thickness of the paper he 5-8ths of an inch; for an Sunch .balloon, 7-8ths of an inch ; and for a 10-inch balloon, let the shell .be 1 inch l-8th thick. Shells designed for stars only, maybe-made quite round, and the thinner they are at the opening, thebetter; for if they are too strong, the stars are apt to break’at thebursting of the shell. When you are making the shell, make useof a pair of calibers, or a round gage, so that you may not lay the

paper.