The Pyrotechnist's Treasury Part 5

Roll the case like a roman candle case, but gauge it to the thickness of a rocket case. Let the inner diameter be 6/8; the outer 9/8; the length of the case 7-1/4 inches, fig. 43. To charge the case, have a mould, as directed for port-fires; and let the tenon rise exactly 3/8 of an inch up the case. Put in a little composition at a time, and mallet it as firmly as possible, till within exactly 3/8 of an inch of the top of the case; so that there will be a vacancy of 3/8 of an inch, at each end.

Fill each of these ends flush with plaster of paris. It is, better, too, if you can manage to fill the middle half-inch of the case with plaster of paris. It can be effected with care, and will hold the screw, hereafter to be described, more firmly.

Construct a wooden box, fig. 44, consisting of a bottom and two sides only, firmly screwed together. Each of the pieces of wood is to be 7-1/4 inches long, and 1/2 an inch thick. The internal breadth of the box is to be exactly 9/8 of an inch; and its internal depth exactly (4-1/2)/8 or 9/16, so that when the tourbillion is laid evenly in it, and pressed down to the bottom, half of the case will be in it, and half out of it.

At a point b, fig. 44, on the top of the side, half an inch from a, make an ink mark: and, at a point d, half an inch from c, make another ink mark. Fig. 45 is the bottom of the box. At a point w, 5/8 of an inch from the end; and, at a point z, 5/8 of an inch from the other end, make holes with a fine bradawl, truly, in a line down the middle of the wood, as between side and side. The distance w z is 6 inches; divide it into 3 equal parts, in the points x and y, two inches asunder. Bisect x y in the point s. Procure 5 carpet pins, fig. 47: they will, probably, be 3/4 of an inch long. Drive them through the holes w, x, s, y, z, inverting the box for the purpose, so that they shall stand bolt upright in the box. Now screw, or nail a piece of wood over the bottom of the box, entirely to cover it, to prevent the carpet pins from getting displaced. It will be seen, that, if the tourbillion be now laid evenly in the box, and pressed down till it rests on the bottom, the projecting pins will make 5 holes, in the under part of the case. While it is thus lying, with a stiletto, such as used by sempstresses, for making eyelet holes, p.r.i.c.k the side of the case over the line b, of fig. 44; and, also, over the point d. There will now be 7 holes; 5 underneath, 1 to the right, and 1 to the left: the latter are the places for the whirlers, or holes of rotation: 4 underneath, for the lifters, or holes of ascension; the centre one, s, receives a nail or screw. Take a bradawl, fig. 49, 3/16 of an inch diameter; and slip over it a s.h.i.+eld, consisting of a piece of wood with a central hole up it, like a pop-gun, of such a length, that, when it is slipped on, only 1/4 of an inch of the bradawl protrudes; or, instead of a bradawl, fix in a handle, a wire of equal length, namely 1/4 of an inch, and file it to a point.

Push this into all the holes, except s, making 4 holes underneath, and 2 horizontal holes, one left, one right: all these holes will be exactly of the same depth, on account of the s.h.i.+eld: see that they are bored perfectly true, the horizontals exactly 90 degrees above the others, or 1/4 of the circ.u.mference.

The next thing required, is a piece of hooping, or curved stick, about 6/8 of an inch broad, and as long as the case, 7-1/4 inches. In the centre of this, bore a hole, and countersink it; then, with a screw, an inch and a quarter long, screw the hooping, at right angles, on the bottom of the case, through the point s of fig. 45, which must be enlarged to receive the screw. A touch of glue may still farther hold the wood in position. It will now a.s.sume the shape of a cross, like figs. 50 and 51. Fig. 50 shows the under side of the case; fig. 51 the upper. From w to x lead a bit of naked match; push the ends into both holes, and secure with a little wetted meal, pressed in with a knife. Do the same with y and z. Paste a piece of double-crown, 3/4 of an inch broad, and of sufficient length, and cover each of the two pieces of match, with two layers of the paper. Turn it over, like to fig. 51; connect the holes a and b with a bit of naked match; and, under the centre of it, slip another piece of naked match, having a piece of touch-paper round the protruding end: cover the match with two thicknesses of pasted paper, in the same manner as the under holes. The tourbillion is now complete. See that it will balance, and swing round easily, when laid upon a level surface. The proper way to fire it, is from a flat sheet of iron, or a flagstone. Light the touch paper; the fire will communicate to the side holes, and set it in rotation. As soon as 1/8 of an inch of fuse has burnt from each end, and the piece has got well into action, the 4 under holes will catch, and cause it to ascend.

Instead of this mode of making a tourbillion, some charge it with an inch of solidly rammed clay, in the middle; fasten the stick, by crossing it with binding-wire; bore a hole through the middle of it, and of the clay, and slip it over a tapering-wire, standing upright in a block, like the spindle of a rocket. Four holes only are then used; two of rotation, and two of ascension; and the whole are fired at once, the match starting from one of the under holes, going to the side hole; over, across, to the other side hole, and on to the other under hole.

Instead of making them with clay in the middle, there is yet a better method of having two cases, each about 4 inches long; and gluing, or fastening them with tin-tacks on a centre-piece, turned with a tenon at each end, fig. 52; two balancing arms, one on each side, must then be fixed to the centre-piece.

In a windmill, as is well known, the vanes, or sails, are set at an angle. There is a toy, made of two slips of tin, forming a cross, and set at an angle, sloping upwards, called the flying dutchman; this, when spun with a string, from a handle like a humming-top, flies up into the air, on escaping from the string. Steel Fliers, with two vanes, are used by sportsmen to practise shooting flying. Small balloons, some years ago, in a room in the Polytechnic Inst.i.tution, free from a current of air, were guided or driven by a similar contrivance, moved by clockwork. The screw-propeller of a s.h.i.+p acts on the same principle. I think it possible that, if two vanes were fixed in the central piece of wood, set at an upward angle of 10, 15, or 20 degrees from the horizontal, they might a.s.sist the ascension, and so cause the tourbillion to reach a greater height; or, the vanes alone might cause it to rise, upon 4 side holes, two to the left, and two to the right, causing it to rotate. The design is shown at fig. 54, the shape of the vane at fig. 53. I have not yet tried it, so offer it only as a suggestion.

FOOTNOTES:

[A] Tourbillion, from _tourbillon_, like postillion, from _postillon_, the i being inserted to approximate the p.r.o.nunciation of the French. In pavilion, from _pavillon_, and vermilion, from _vermillon_, one l is dropped; so in battalion, from _bataillon_; while medallion, from _medaillon_, retains the ll.

_SAXONS._

These are unchoked cases, charged like a tourbillion, but pierced only with holes of rotation, for the purpose of turning a coloured fire.

Drive them in a mould, as directed before. A good size is, 5/8 internal, 7/8 external, 6 or 7 inches long. Let the tenon enter the case 3/8 of an inch: charge the composition firm till within 1/2 an inch of the top, which leave vacant. Remove it, and fill the 3/8 occupied by the tenon, with plaster of paris. Have a centre-piece, turned like fig. 55, with a tenon, 5/8 diameter at each end, 1/2 an inch long. Glue a case on each tenon. Let the centre-piece be 6 inches long, exclusive of the tenons; so, if the saxon cases are 7 inches long, each, the entire length, as fig. 56, will be 20 inches. Make a hole at a, and another at c, with a s.h.i.+elded bradawl, 3/16 of an inch diameter. Put a bit of naked match in the hole a, carry it round x and y, along to c and on to z. It must be pushed into c with a blunt wire. Cover it with two thicknesses of pasted paper, like the tourbillion. Leave the match exposed at x, y, and at z, and brush it over with meal paste. If the central piece of wood were now put on a horizontal spindle, and fire communicated to the match z, the holes a and c would cause it to rotate, and produce a white circle of fire. This, however, would be hardly worth making; but, by fixing at b, a little case of coloured fire, a splendid effect is produced. This case of colour is usually tied to a nail, driven in at b; but a little tenon of wood may be glued there instead, and the case of colour must be then charged, with a vacancy at the bottom, to fit on the tenon. The case of colour must be timed to burn as long as the saxon; rather more than an inch will be sufficient.

Saxons are sometimes made by charging a roman candle case with an inch of clay in the middle, and boring a hole through the clay, to receive a spindle. Only one half of the case burns at a time; a leader, placed at the bottom, near the central clay, conveys the fire to the other end; and continues the rotation. For distinction, they are called Chinese fliers.

_FIVE-POINTED STARS._

These are cases about 2-1/2 inches long, and 1 inch diameter. Make a bottom to the case with 1/4 inch thickness of plaster of paris, so that it looks like a large pill box. Charge it solid, and at 3/8 of an inch from the extremity, that is, 1/8 of an inch beyond the plaster bottom, round the circ.u.mference make five holes, as for saxons; run a bit of match round, connecting the holes. These, when fired, stand out at right angles, the plaster towards the spectator, so that the fire resembles a gas star, with 5 points, as in fig. 130.

_SQUIBS._

Take a sheet of 60-lb. imperial brown, and a sheet of 12-lb. white demy.

The imperial, as said before, is 29 by 22-1/2. Cut it into 24 equal parts (2, 4, 3), that is, first into two equal parts, down the natural fold of the paper; then each into four equal parts, at right angles to the first fold; and each of these into three equal parts, at right angles to the second fold. Each piece will then be 5-5/8 by 4-5/8. The demy is 22-1/2 by 17-1/2. Cut the sheet into sixteen equal parts (2, 4, 2), each piece will be 5-5/8 by 4-3/8. A piece of brown and a piece of white will make a case 5-5/8 inches long. For a former, procure a piece of bra.s.s wire, or stair-rod, about a foot long, and 1/4 inch diameter.

Lay eight pieces of the demy evenly on each other; draw the thumbnail of the right hand from the farther edge of the paper straight over the middle towards you, a few times. If properly performed, this will draw piece behind piece; proceed till about 1/8 of an inch of each is left exposed, in the same manner as a pack of cards would arrange themselves, if set upright, and allowed to fall forwards; something after the manner of the laths of a venetian blind, or slates upon a roof, imbricated. If you cannot acquire the knack of doing this, you must so lay them, one by one. Paste the edges of all the eight pieces thus lying. Place one of the pieces of brown paper before you; lay the former, or stair-rod, across it, nearly in the middle; bend the paper over it, and press it in with the fingers of both hands; roll for an inch, or so; lay it on the middle of a white piece; bend the white over; infold the brown in it, and roll forward, till it catches the pasted part, and sticks. After a number have been prepared, and are dry, choke them, as directed for rockets. The wire of the choker, fig. 24, should be about 1/16 of an inch thick. Now take a piece of square steel, or iron wire, 12 inches long, the thickness of the wire being about 3/5 the diameter of the stair-rod, that is, 1/4 x 3/5 = 3/20 of an inch; if it be found difficult to procure square wire, file a round piece. Bore a hole down a bradawl or chisel handle, 2 inches in depth, and 1/4 diameter; fix the square wire in it, with melted lead, like fig. 4; the lead is for the purpose of giving weight to the blows in charging. Black the wire all over with ink, and allow it to dry. The next requisite is a tin funnel, without a neck, of the size and shape of fig. 65. Any tinman will readily make one to order; but if the learner procure a soldering-tool, he can construct one himself. For this purpose, dissolve a piece of zinc in a little hydrochloric or muriatic acid, till the acid is saturated: heat the tool, and dip the tip end, momently, into it; the acid combines with the oxide of copper formed by heating, and the zinc adheres to the clear surface of copper produced; it will now easily take up the solder: the joint to be soldered must be clean, and also touched with a feather dipped into the acid. It is best to make a funnel with a piece of writing-paper, first, for a pattern; when this is got correct, the tin can be cut according to it. By describing a circle with a 3-inch radius, and cutting out a sector of 100, the correct size is obtained at once; 1/8 of an inch breadth, outside the radius, is to be allowed to lap over. The bore of the squib is 5/20 of an inch; the size of the ramming wire 3/20; the hole at the bottom of the funnel may be half way between, 4/20 or 1/5 of an inch diameter. Push the wire rammer through the funnel, till it protrudes 2 inches beyond the bottom; observe the part of the wire which is now level with the top of the funnel; withdraw it, and file a bright mark round the part: it will be about 4-1/2 inches from the end. The wire, having been inked, shows the bright mark more plainly.

Make a deal box, 3 inches square, and 4 inches deep, and nail a bottom to it. Also have a little nipple, fig. 73, with a wire, as drawn; it can be secured to a flat board.

To charge the cases. Set the choked end of one on the nipple, insert the funnel in the other end, put the wire rammer down through the funnel, and let it fall to the bottom of the case: put in some fuse, and jolt the rammer up and down, till the case gets so far filled, that the bright, filed notch, before described, is on a level with the top of the funnel. It is necessary to sit at a table to charge the cases; the eye is, then, on a proper level to see the mark. As the cases are thus charged, set them in the square box, choked end downwards, till a number are filled. Now take out a handful, invert them over a sheet of paper, and give them a few taps with the rammer; this will shake out a great deal of loose composition, that has got puffed up, in the case. Return them to the deal box.

The next operation is to bounce, or bang them. For this purpose take a long slip of paper, 7 inches broad. Stretch it lengthwise before you.

Lay a number of the cases upon it, so that all the choke ends lie flush with the left edge of the paper; then roll them up in the paper; turn and set them upright on the choke ends; the paper will now stand up more than an inch above the cases, as a tumbler, three parts full of water, stands up with an empty s.p.a.ce above the water. Rest them on a sheet of paper, and pour in a quant.i.ty of F grain powder; this will fill every case; loosen the paper wrapper, and allow the superfluous grain powder to fall on the paper. Set the cases, choke downwards, in the square box.

As they are all full, it is necessary to get a little out of each. For this purpose, lay the square box, containing them, horizontally on a sheet of paper, on one of its sides; turn it gently over, and lay it on the next side; a little of the gunpowder will spill out; turn it gently over again, and lay it on the next side; and so proceed, till every case has about 3/8 of an inch empty. The ends of the cases are now to be closed. Take a case, in the left hand, as in fig. 63, and wind a piece of string, or whipcord, three or four times round it, holding the end of the string, a, firmly with the thumb; then, with the right hand, bring the end, b, back over all the folds, as in fig. 64; pull the end, B, tight, and the case will be closed.

Melt some common bottle sealing-wax in a pipkin; carry it to a distance from the fire, and dip the ends of the squibs into it. Next, prime them, by pressing the choked ends into very slightly damped meal powder, as directed for wheel cases. Take a piece of touch-paper, 15 inches by 10.

Divide it into 48 pieces (2, 2, 3, 4); each piece will be 2-1/2 by 1-1/4. Roll a piece round the primed end, twist to a point, and fasten it with a bit of carpet thread, hitched three times round it.

_SERPENTS._

These are simply squibs, made short, in order to burn out quickly, as they are intended to be thrown from mines, and would otherwise lie too long on the ground. They are best made entirely of brown paper, pasted all over, exactly like wheel cases, and choked in the same manner. Cut the paper 6 inches by 2-1/2, and roll them on the squib former, so that they shall be 2-1/2 inches long. Ram them with the funnel and wire, but continue the ramming till the guide-mark stands a little higher than the level of the funnel; until, in fact, the cases get half full. Bounce, close, and dip them in melted wax, like squibs. The best way to prime them is to paint them with the sash-tool, slightly, then plunge them into dry meal, so that they may be, as nearly as possible, like quickmatch. If they were pressed into wet meal powder, of the consistency of mortar, and then rubbed smooth on a Dutch tile, or slate, or plate, they would dry hard and glazed. In this case, if they were fired from a mine, in all probability three-fourths of them would miss. In brus.h.i.+ng them with the sash-tool, with meal paste, turn the brush well round, to leave little in; so that, after being pressed into the dry meal, they may not be choked up, but the cup shape still be left. They are not to be touch-papered, being intended only for mines, rockets, or sh.e.l.ls.

_PINWHEELS._

Procure some 16-lb. double-crown white paper.

A sheet is 30 20 inches.

Cut off a strip 30 3 ------- Leaves a piece 30 17

The small strip may be used for odd purposes. Divide the 30 by 17 into 10 strips, each 3 by 17, for penny pinwheels. If the paper were cut the other way of the sheet, it would not wind smoothly, but crumple up. The fibres, from some cause or other, appear to arrange themselves in one direction, like the grain in wood. For halfpenny wheels, divide the sheet into two pieces, each 10 by 30; then cut each of these into 12, each 10 by 2-1/2. For a former, have a straight piece of iron, or steel, wire, 1/8 of an inch thick, and 24 inches long. One end of this must have a basil, or sloping enlargement upon it, which is thus made. Take a piece of double-crown 4 inches square; lay it straight before you, and cut it diagonally, from the right top corner to the left bottom corner; remove the left half; paste the right; lay the wire upon it, so that the rectangular corner is 5 inches from the right end of the wire; roll it up, and press it smooth; the sloping edge will now form a spiral, commencing at 9 inches from the right end of the wire, and being enlarged at 5 inches from the end. Paste a thin strip of paper over the whole, to protect the spiral edges. It will now be something of the shape of fig. 27, only turned the reverse way. The 5 inches at the end are for a handle. To roll the pinwheel pipes, lay the strips of paper evenly upon each other, and work them back with the thumbnail, as before. Paste the edges; lay half-a-quire of double-crown, or of blotting-paper, flat upon the table, to roll on. Place one of the strips of pasted paper upon it; lay the wire upon it, the basil end being towards the right hand; the wire is to be laid, not quite parallel with the near edge of the paper, but slightly sloping, about an inch and a quarter distant from it on the left, and not quite an inch on the right, or basil end. So much of the basil must lie on the paper as will make the mouth of the pipe large enough for the nozzle of the funnel to enter half-an-inch. The basil, of course, gathers up the paper more quickly than the wire, and brings the edge straight, on the completion of the pipe. Now to roll, bend the paper over the left end of the wire, press it in with the fingers, and begin immediately to move it forward; at the same time draw the fingers of the right hand rapidly along, pressing in the paper, and rolling forward, keeping the right, or basil, end of the wire tight, and slightly pulled towards you: the paper round the left end of the wire will have thus become rolled half round the circ.u.mference of the wire, before the basil end has begun. There is very great difficulty, at first, in rolling so long a pipe as 17 inches; it is advisable to begin with the halfpenny pipes, which are much shorter; the same wire-former will serve for both. If you cannot succeed, get a person to help you; sixteen fingers can manage the matter easily; but it is best to master the difficulty yourself. Have a funnel as nearly the size and shape of fig. 66 as possible. It is best with a lid soldered on the top, with a circular hole in the middle, about the size of a s.h.i.+lling, to prevent the composition from getting spilt. A slightly tapering neck is also to be soldered on at the bottom. Take especial care that the mouth of the funnel dips into the neck, and not have the neck sticking up in the funnel. The joint inside must be perfectly smooth. A charging wire will now be required; this should be a square steel wire, as large as the neck of the funnel will admit, to move easily up and down; let it also have a piece of lead at the end, to give it weight. Take a piece of bra.s.s tube, about 3/8 of an inch diameter, and an inch long. Hold the wire in it, with a piece of flannel, or woollen cloth, and pour in melted lead. To charge the cases, first bend a quarter of an inch of the small end of the pipe, over the edge of a knife, into a hook, to prevent the composition running out; insert the nozzle of the funnel in the enlarged end; hold the part of the pipe now round it, with the thumb and forefinger of the left hand, slip the wire, through the funnel, down to the bottom of the pipe, which must rest, for a moment, on the table; pour in the composition, jolt the wire up and down; lift the pipe from the table, keep jolting the wire, at the same time turning it round, and let the pipe swing slightly to and fro, till filled. A guide-mark must be filed round the wire, as for squibs, at such a distance as that, when it is level with the top of the funnel, the bottom may protrude about 3/8 of an inch. When a number of pipes are charged, close the large, or basilled, end, which is the one to be lit, by means of a piece of whipcord, or thin twine, wound round it, as directed in figs. 63 and 64.

Soak a towel in water; wring it as dry as possible; spread it out flat; lay the pipes in a row, side by side, upon it, like rushes in a chair bottom; roll them up in it, and leave them for 10 or 15 minutes. Then wind them upon the usual circular blocks, and fasten the end with sealing-wax. Be careful that the wax is not in a flame at the moment of touching the case; if necessary, blow it out. Accidents will arise, both from the wax and from the candle, if care is not used. Measure, with a tape, round the wheel, now wound; suppose 4 inches; cut a piece of blue double-crown, 4 inches broad, and any length: cut this into strips about 3/16 of an inch broad, and 4 inches long; paste a slate all over; lay these strips, 7 or 8 of them, side by side, flat upon it; paste their upper surface; lay one across each pinwheel, and bend it over to make the ends meet in the centre on the other side. If you wish the pinwheel to be of double or triple size, after you have charged one pipe, paste the small end of a second pipe, outside, and stick it in the other. Let it dry; then charge the additional pipe. Observe, the pipes must not lie too long in the towel; if the nitre gets dissolved, it soaks into the paper, which becomes, virtually, touchpaper, and one pipe ignites the other. The wire formers must not be allowed to get rusty; therefore, before laying them aside smear them with tallow, or olive oil. The wire is much facilitated, too, in delivering, if, just before using it, it is slightly oiled, and then wiped, apparently, perfectly dry. After the wheels are finished, they should be spread out to dry, as soon as possible. It is not usual to prime them; and, as sold, they are very difficult and troublesome to light; for private use, they may have a short piece of match inserted in the mouth, and a small bit of touch-paper wound round it. French nails are now made, of wire, very thin; those, about an inch long, are much better than pins, for firing the wheel upon, as they have larger heads, and prevent its falling off.

Pinwheel blocks may be obtained of Merrick, Shuttle Maker, 155, Bethnal Green Road; the same person sells triangular and vertical wheels; caprice, furilona and pigeon frames; rocket sticks; mine bottoms; saxon centres, &c.; also, plait mills, made to order.

_CRACKERS._

A good tough paper for these is 24 mill, 19-lb. double-small hand.

A sheet is 30 20 inches.

Cut off a strip 30 4 ------- Leaves a piece 30 16

The strip 30 by 4 may be used for squibs, or any odd purpose. For penny crackers cut the 30 by 16 into 8 strips, each 3-3/4 by 16. For halfpenny crackers divide the sheet into 2 pieces, each 10 by 30. Cut each of these into 10, each 10 by 3. For a former have a straight piece of iron, or steel, wire, 3/20 of an inch diameter, and 24 inches long. This will not require a basil. Have, also, another wire, of half the thickness, for an opening wire. Lay the strips on blotting-paper, as before; and place the wire parallel with the edge of the strip, as there is now no basil. When a number of pipes are rolled and dry, hold one flat on a table; and, with the handle of a knife, or tooth-brush, rub the pipe flat along, all except the first half-inch, held in the left hand, to form a little cup. Now push the opening wire through it, to partially open it. Bend the bottom, over a knife, into a little hook, as before directed, for pinwheels. Take up a quant.i.ty; wind a strip of paper round them, as in banging squibs, and pour in a quant.i.ty of FFF, or canister powder. Unless the powder is very fine it will not run down. Pipes may be filled with F grain powder, one at a time, by putting a funnel into the cup part, and tapping the pipe with a wire. You can hear the powder run down, and easily judge when the pipe is full. The powder is now to be crushed into meal, by rolling the pipes through a plait mill, fig.

71. This is furnished with a wooden screw, at top; the screw presses upon a cross-bit, which bears upon two movable collars: these rest on the axis of the top cylinder, by which means the pressure can be adjusted as desired. The cylinders of plait mills are of beech, or boxwood; the latter are, of course, the best; but for making great numbers of crackers, it is necessary to have the frames of iron, and the cylinders of steel. If a mill cannot be procured, the pipes may be rolled with a bra.s.s tube, or rolling-pin, or pa.s.sed through an American mangle; but a very good, and far less expensive plan, is to lay them on an anvil, or flat-iron turned upside down, and beat them with a smooth-faced hammer; this is a tedious process, but it makes good crackers. The cup end, having served its purpose, is to be flattened, and bent into a hook. Now lay the pipes in a damp towel, like the pinwheels. Take two pieces of deal, each about 6 inches long and 1-1/2 inch broad: let the one for the halfpenny crackers be 3/4 of an inch thick; the other, for the penny, 1 inch thick. Saw and chisel a piece out of each, about 4 inches long and 1/2 an inch broad, as drawn, fig.

67, so that it looks like the first and third fingers of the hand held straight up, with the second finger, between them, shut. Next procure 20 pieces of wire, each 2 inches long, and about 1/16 of an inch thick.

Support the cracker-frame in a vice: lay the cracker across the opening; place a wire upon it, as at a, fig. 68; bend the pipe over it; lay on it another wire, on the other side, as b; bend back, and lay on it the wire c; and so on, alternately, till the cracker is bent up. Lift it out of the frame, and let the wires drop. The distance between the wires, in the halfpenny crackers, will be 3/4 of an inch; in the penny, 1 inch; if made according to the directions given. The outside of the frame should be very slightly tapered, or it will be difficult to lift the cracker up out of it. The penny size will probably take 14 wires; the halfpenny 10 wires. Cut the end flush, to expose the crushed powder; wind round it a piece of touch-paper, about 1-3/4 inch long, 1-1/4 broad; it need not be pasted; fold up the cracker; pa.s.s a piece of flax or thread twice round it; twist the thread in and out, backwards and forwards, among the folds; and the cracker is complete. If the paper does not appear sufficiently thick to make a good report, cut the strips broader, and fewer to the sheet; but always cut them up the short way of the paper, or they will not bend properly. The paper for pinwheels and crackers is 30 inches by 20; the longest pipe that can be cut is 20 inches: as an experiment, try a pinwheel and cracker the other way of the paper. If the cracker is intended to be put into a jack-in-the-box, sh.e.l.l, or rocket head, push a bradawl up the mouth, insert a bit of quickmatch, to project a quarter of an inch, and secure it with a little wetted meal, pressed in with a knife. The way of bending it is shown at fig.

69. It is not necessary that a cracker should contain very much powder; the loudness of the bang depends more upon the thickness of the paper than upon the quant.i.ty of the powder. So with maroons; more string and less powder, are better than more powder and less string. A very good paper for crackers is 30-lb. royal cartridge; cut the strips 3 inches broad; 16-lb. double-crown may also be used, the strips 5 inches broad.

Crackers for mines may be made with brown paper.