A New Method.

Put into a gallipot, or basin, some hot starch, made as before directed, or some cold gum-water, or cold dextrine solution; and with a small stencil-brush, or a 3⁄8 sash-tool, cut across the middle to make the bristles short and stubby, stir in some meal-powder, till it is well mixed and looks like black paint. To avoid repetition, it will be convenient to refer to this under the name of Meal-paste. Take two towel-horses, fig. 14, and set them parallel 5, 10, or 20 feet apart. In the top rail of each, drive four nails 1⁄2 an inch asunder. Fix the dry cotton to the nail a, carry it across to the opposite nail b, pass it round the second nail c, bring it to the opposite second nail, and so on, till the cotton lies in four parallel lines, like the strings of a harp placed horizontally. Hitch the cotton, without cutting it, to the hook of the weight, fig. 15. This weight is made by taking a piece of brass tube, 1 inch diameter, and 4 inches long. Stop one end with a bung, fill it with melted lead; and before it sets push in a lucifer match, having previously cut off the priming. As soon as the lead is cold, pull out the match, which having been partially burnt smaller, will come out easily, and in the hole left by it screw a cup-hook, as drawn. Invert the weight, pick out the bung, and fill its place with more melted lead. Now procure two pieces of planed deal board; one 4 inches square, the other 6 inches square. With the left hand hold the smaller piece close underneath the cotton; and with the sash-tool or stencil-brush, work the meal-paste well into the fibres of the threads, pressing the cotton on the board till it is thoroughly soaked, and rolling it over, laterally, to make it as round and smooth as possible. It is best to begin on the left, and work towards the right. If the wetting slackens the threads, pull them tight. Now brush some meal-powder through a fine sieve, to free it from lumps; put a tablespoonful or two upon the larger board; hold it close under the four threads, as the other, with the left hand, and move it laterally forwards and backwards, and down the whole length, at the same time brushing the meal over the threads, with a soft, dry, sash-tool, till they are smothered, and giving them an occasional jar to shake off the superfluous meal. By a little practice they may be made as smooth and as round as a piece of wire. Leave the weight hanging to them till they are dry. Instead of four nails on each rail, a dozen may be put; and if the towel-horses are set 12 yards apart, 144 yards may be soon made. In this case, three or four heavier weights would be required. These contrivances, however, are by no means necessary for an amateur; four hooks or nails opposite four others, anyhow supported, will be sufficient; and six or eight feet apart is a good distance. A small quantity may thus be made one day, and a small quantity another; and for this purpose it is best to use gum-water, as it is always ready, and a little can be added to the dry left the day before, and a little fresh meal stirred in. Three or four threads of white darning-cotton, which is of two twists, make very good match; knitting or crochet cotton, which is of three twists, produces, alone, excellent match; two or three pieces of the first, or two of the latter, put into a leader pipe, side by side, blow through with a violent report. Match may also be made of the very narrowest white tape, 3⁄16 of an inch broad; this, from its flatness, is peculiarly suited for enveloped stars. For general purposes, however, lamp cotton is decidedly the best, as it is most loosely twisted, and therefore the most absorbent. If match is liable to be exposed to damp, it should be cased in thick leaders, and be prepared with starch; in other respects, nothing can surpass gum-water. Of course iron pound-weights, with a ring in them, will answer the purpose, or an iron pestle tied to the cotton, or anything heavy; but the kind I have advised are most convenient. They will weigh about a pound and a quarter each. The weight may hang over a chair-back.

Match, to be perfect, ought, when cut across, to look black throughout; it should, also, be stiff, straight, and round; but, to test it, cut off about 10 inches; put one end of this into a leader pipe, so that 5 inches will be in the pipe, and 5 out. Hold the end of the leader with a pair of tongs, or lay it on the ground; light the naked end. If the match is good it will burn gradually, though swiftly, till it gets to the pipe; it will then blow through with a bang. The nearer the leader pipe fits the match the better, only it ought to be large enough to allow it to go easily in, without force: if laid in a roman candle case it would hardly puff: the smaller and smaller the tube becomes the louder and louder the report: the increase of power being in the inverse ratio of the diminution of space. A train of gunpowder laid in the open air, or confined in a tube, comports itself in the same way, as is well known. Match, when dry, should be kept straight; for, if it gets broken, it acts like a cracker, snapping at every break.

A piece of zinc rainwater pipe, of suitable length, furnished with a bottom and lid, or a couple of bungs, is convenient for keeping it in; but a far better contrivance is a deal box, 5 feet long, 3 inches deep, and 3 broad, made of 1⁄2-inch pine. The lid of this box can be readily furnished with three or five hinges, like a piano, only made with string instead of brass. Take two pieces of string, fig. 57, and tie them in a knot near the end, as at k. At x, fig. 58, make a bradawl hole through the back of the box, near the top, and push the strings through it; make another hole through the lid, put the string through it, and tie in a knot on the top, as at z: and so with the other four. This will render the explanation easier to understand; but, practically, a single piece of thicker string is best, if you can manage to tie the second knot in the exact spot you wish. The knots must not be too close to each other, as the lid requires a little play. For safety, the box ought to be furnished with a lock.

[ROCKETS.]

Rockets are charged in choked cases, on a spindle, to leave a hollow up the middle, through which the fire may be communicated to nearly the whole of the composition at once: this causes the sudden generation of an enormous quantity of elastic vapour, which, being unable to escape instantly through the contracted aperture left for its exit, exerts its pressure in the contrary direction, and hurries the rocket forward. A stick, attached to it, guides it, like the rudder of a vessel, or tail of a bird, or fish; while its weight and leverage keep the centre of gravity a little below the case, and prevent the rocket from pitching over. Its manufacture, therefore, from the commencement of cutting the paper for the case, to its finish of fitting on the stick, requires an accurate adjustment of all its parts. Disregarding the trade names of pound, ounce, &c., which, now that moulds are dispensed with, are useful only for enabling the makers, from tradition, to understand each other; the internal diameter, instead of the external, as formerly, may be selected, from which to compute the relative measures. Taking the bore of the case as unity, the proportions will be as follow:—

1Internal diameter of case.
11⁄2External diameter.
8Length of case.
6Length of spindle.
3⁄5Bottom diameter of spindle.
64Length of stick.
1⁄2 by 1⁄2 Thickness and breadth of stick.

These proportions are most readily calculated by taking the diameter in eighths of an inch. Selecting, for instance, a 6⁄8 rocket, we have, 6⁄8, inner diameter; half as much again, 9⁄8, outer diameter.

Taking the numerator as inches: 6 inches, length of case; 3⁄4 of this, or, which is the same, 1⁄2 the outer diameter, as inches, 41⁄2 inches, length of spindle; putting 20 for the denominator, instead of 8 (8 being 2⁄5 of 20), 6⁄20 of an inch, bottom diameter of spindle; 6 × 8, (numerator multiplied by denominator) = 48 inches, length of stick; 3⁄8 by 3⁄8, size of stick.

The following table exhibits the usual sizes in inches.

Name of
Rocket.		Inner
Diameter.		Outer
Diameter. 		Length
of Case.		Length of
Spindle.		Bottom
Diam. of
Spindle.		Length of Stick.Size of Stick.
10/810/815/81071⁄210/2010 times 8=805/8 by 5/8
9/89/8131⁄2/8963⁄49/209 times 8=7241⁄2/8 by 41⁄2/8
8/88/812/8868/208 times 8=644/8 by 4/8
7/87/8101⁄2/8751⁄47/207 times 8=5631⁄2/8 by 31⁄2/8
6/86/89/8641⁄26/206 times 8=483/8 by 3/8
5/85/871⁄2/8533⁄45/205 times 8=4021⁄2/8 by 21⁄2/8
41⁄2/841⁄2/863⁄4/841⁄233⁄841⁄2/2041⁄2 times 8=3621⁄4/8 by 21⁄4/8
4/84/86/8434/204 times 8=322/8 by 2/8
3/83/841⁄2/8321⁄43/203 times 8=2411⁄2/8 by 11⁄2/8

To Make a 6⁄8 Rocket.

Have the former, fig. 7, a brass tube 6⁄8 of an inch external diameter; the gauge, fig. 8, with a 9⁄8 aperture; procure some imperial brown paper, 70 lb. or 84 lb., the thicker and heavier the better. The best kind is made of old ropes, is air-dried, and rough. This is not easily obtained now. The smooth machine-made, cylinder-dried answers very well. The sort used for laying under carpets, and which is 5 feet broad, is almost equal to the original rough imperial, and should be procured, if possible, in preference to the smooth. Cut it into strips 6 inches wide. Paste the pieces well, and roll the cases as hard as possible, with the rolling board fig. 6, till they fit the gauge. Lay them by for a few hours to get partially dry. They must, then, be choked or strangled, about half a diameter from one end of the case, that end that lay nearest to the left hand in rolling, till they assume the shape of the neck of a vial. For this purpose have a cylindrical piece of deal, alder, or any kind of wood, fig. 24, about 9 or 10 inches long, made to fit easily into the case; cut it into 2 pieces, a and b; b may be an inch and a half long; round off the ends, just cut. In a, fasten a screw, the solid wire, or uncut part of which, is 1⁄4 of an inch thick; saw, or file off the head, and slightly taper the part projecting; in the piece b bore a hole to just fit the wire of a. Slip b upon a, and push them into the case, so that the interval between the two reaches within about 1⁄2 an inch of one end of the case; slightly draw out b, to leave a neck, or hollow, round which to form the choke; fix a staple, or screw-eye in a post: tie to it one end of a piece of cord, about a yard long, and 1⁄10 of an inch thick; fasten the other end round the middle of a stick, for a handle; take hold of the stick with the right hand; hold the case in the left; pass the cord round the space left vacant and gradually tighten it, turning the case round and round, so as to pinch it in equally on all sides, till it assumes the shape of fig. 23. Hitch a piece of string, about 1⁄16 of an inch thick, a few times round the neck, until it is filled up flush with the other part of the case, remove the choker, and hang the case up to dry. A hitch is made by simply bending the string backwards into a loop, like fig. 22; passing it round the choke; pulling it tight; looping it again, again passing it round the choke, and so on. The first loop is called a half hitch, and will not hold of itself; the second loop completes the hitch, and makes it hold: the remaining hitches are for filling up the choke, and restoring the cylindrical shape. Practise, by hitching the string upon your thumb, 4 or 5 times: it will hold after the second loop; but push it off at the end, and it will all fall loose again.

A case must not be choked when wet, or it will tear; nor must it be too dry, or it will be difficult to choke it at all. The drier, however, it can be choked, the better. Experience is the only guide. If properly dry, the wrinkles of the choke will be small, and perfectly regular. Should the string stick to the case, chalk it; but this is not likely to occur unless the paper is too wet. Have a foot, fig. 16, turned of ash, or beech, or box, with a hemispherical nipple, 6⁄8 of an inch diameter, as drawn. Bore it with a twist drill, or nosebit, to the depth of an inch and a half. Procure a brass, iron, or steel wire, but preferably brass, 6 inches long, and 3⁄10 of an inch diameter, and perfectly straight. Cut, on one end of it, a screw, 11⁄2 inch long, fix it in a vice, wet the screw with glue, and screw the foot on. File the 41⁄2 inches gradually tapering. The object of tapering it is simply to make it deliver. A cylindrical hollow up the rocket would answer as well, but the spindle could not be got out. The more conically true it is tapered, of course, the better. Finish it off with a very fine file, and smooth it with glass paper. The block into which it is screwed may be larger than drawn; the bottom should be turned slightly concave, to make it stand firm, on the same principle as the bottoms of plates, cups, &c., are made with a rim. The block and spindle are better if cast in gun-metal, in one solid piece: the pattern to give to the caster should be in one solid piece of wood. After casting, the rough parts must be filed smooth; not many turners will be found willing to undertake to turn it.

The next articles required are a setting-down piece, fig. 17; three hollow rammers, or drifts, figs. 18, 19, and 20; and one solid rammer, fig. 21. They are simply cylindrical pieces of wood, turned with a head, to bear the blows of the mallet. Beech, or box free from knots, will answer. The lengths of figs. 18, 19, 20, and 21, are to be 8, 6, 4, and 2 diameters, respectively, exclusive of the head; that is, 6, 41⁄2, 3, and 11⁄2 inches. The hollow drifts are to have a cylindrical, not conical, hole, bored up them, with a nosebit, or twist drill, to within one inch of the handle, so as to clear the spindle by 1⁄2 an inch, to allow of any dust being driven up it. The hollow in figs. 17 and 18 must be large enough to fit the spindle loosely at a; in fig. 19, a trifle smaller, to fit loosely at b; and in fig. 20, a trifle smaller still, to fit loosely at c.

The next requisite is a mallet, fig. 25, which may be of ash, or beech. It may be a cylinder, 5 inches long, and 3 inches diameter, with a handle about 5 inches long, and 1 inch diameter. Let it be turned at the end slightly concave, like the bottom of fig. 16, that it may be set to stand upright, like a wine bottle. Or the head may be made 3 inches square, like fig. 26; or, a small carpenter's mallet, about a pound and a quarter weight, will answer.