Part 6
Pounds. Calibre. Pounds. Calibre. Pounds. Calibre. 1 100 20 271 39 339 2 126 21 275 40 341 3 144 22 282 41 344 4 158 23 284 42 347 5 171 24 288 43 350 6 181 25 292 44 353 7 191 26 296 45 355 8 200 27 300 46 358 9 208 28 304 47 361 10 215 29 307 48 363 11 222 30 310 49 366 12 228 31 214 50 368 13 235 32 317 51 371 14 241 33 320 52 373 15 247 34 323 53 376 16 252 35 326 54 378 17 257 36 330 55 380 18 262 37 333 56 382 19 267 38 336 57 385
By this Table, the weight of the ball being given, the size of the mould may be found after the following manner: suppose it be 18 pounds; opposite to it, in the column of calibres, is 262; then say by the rule of proportion, as 100 is to 19 and a half, so is 262 to a fourth term, viz. 51.09 which is the number of lines of the calibre required; therefore, the Calibre of a Rocket of 18 pounds, will be 52 lines nearly, or 4 inches and 4 lines. The calibre may be also found by multiplying the number answering to the pounds by 19½, and cutting off from the product the two last figures; thus suppose the number be 252, which multiply by 19½, the product 4914 separated by the decimal point will give 49.14, or four inches a line and one-eighth.
Now suppose the calibre to be given in lines, the weight of the ball may be found with equal ease, e. g. if the calibre given be 36 lines, then as 19½ : 100 :: 36 : 184; the nearest number in the table to this is 181, which shews that the weight of the ball will be rather more than six pounds; therefore a Rocket, the calibre of which is 36 lines, is a Rocket of a six pound ball.
REMARKS ON THE FOREGOING TABLES.
TABLE I gives the dimensions of Rocket moulds when the Rockets are rammed solid; it was calculated, as its Author informs us, from repeated experiments; we insert it for the information of our readers, but we would advise none to practise the method of solid ramming.
TABLE II.--This table may be perfectly understood by the explanation given of its use, and from considering that a lead bullet of a pound weight, is just 19½ lines in diameter, as may be proved by experiment; the inferior numbers are likewise the diameters of the inferior weight.
TABLE III.--This table is only an extension of the latter, although its arrangement is somewhat different; for if 19½, the diameter of a ball weighing one pound, be assumed as unity with any number of cyphers, answering to the number of parts which the same diameter is divided into, (which may be done by means of the diagonal scale,) let this number be 100, which answers to one in the column of pounds:--that is to say, if you assume 100 for the first number, and it be rose to the third power,[11] your first cube will be 1,000,000, the cube root of which (being 100) must be placed in your table as the first root, and answering to unity in the column of pounds: then for the second number, which is two pounds, we must extract the cube root of double that number, viz. 2,000,000, which will be 126 nearly, (or continued to more places 1,259,921) and this will be the second number in your Table; and in the same manner will the third number be found, that is, by trebling the first cube and extracting the root as before, which will be 144, and so of the fifth, sixth, &c. to the end of the table. These tables are indispensable in the making of Rockets, in order to preserve an uniformity in Rockets of the same kind, and to render more certain their effects, as has been corroborated by repeated experiments.
_Preparing the Cartridges._--For this purpose large stiff paper of a particular kind is to be used; namely, that which from being principally used for this purpose, is known by the name of _Cartridge paper_. For cases from the smallest size, up to five or six pounds, this is the best material we can employ; it must be wrapped round the former, (whose proportion to the mould we have already given) till it fits tight into the cylinder, and the last fold secured by means of common paste. If some thin paste is used throughout the rolling, the cases will be much improved.
For Rockets of a larger size, the cases must be made of some stronger material, such as pasteboard, of the thin and inferior kind, the folds of which must be well secured with some strong paste or glue. In making the cases a pattern of the outer fold, with one end sloped off, should be preserved for each size, and on it marked the number of sheets or folds requisite to make that size cartridge. This method will help to ensure a regularity in the make and formation of the cases.
The paper being prepared of the proper size, one part of the first sheet must be folded down so far, that the double thickness will go two or three times round the _former_; the _former_ is then to be laid on this double edge, and the handle projecting over the table, the paper is to be wrapt round within two or three turns; when a second sheet is to be laid on the loose part of the first, and then roll the whole of it tight and evenly on the former; these two sheets should be of lengths sufficient for the size of the case, but if they are not, a third must be added in the same manner as the second.
For the purpose of rolling the cases tight and even, they are passed two or three times under the _rolling-board_, (which is a smooth piece of deal about eighteen inches long, and in breadth equal to the length of the Rocket, with a handle at the top, when complete something similar to a plaisterer’s float;) taking care to roll them the same way as in rolling them on the former.
The cartridge being formed to the proper size, and the last fold being secured by paste, &c. it is now to receive the contraction, or, as it is generally termed, the choak; which is effected by the simple apparatus represented by Fig. 7. Let the former and small end-piece be now joined by means of their connecting wire, and let the short piece be thrust into the case as far as the line B, marked round it for the purpose; then pass the cord once round the case, exactly over the juncture of the formers, and at first press gently with the foot on the treadle, and keep rolling the case on the line, which will cause the choak to be free from wrinkles and other inequalities.
Cases of small dimensions may be easily contracted after the above manner, but when of larger size, they will present more resistance to the choaking cord than it will be able to overcome; but this difficulty may be obviated, by moistening with water the end of the case, and choaking it previous to the envelope of the last sheet; which may then be put on, and again choaked, and the contraction well secured by twine, or strong waxed thread, which must be passed several times round the cartridge, and afterwards secured by two or three running knots made one above another.
The case (still remaining on the former,) is now to be inserted into the cylindrical mould without its foot, and set upon some solid block, and the former driven hard upon its end-piece, so as to make the contraction smooth and close; after which the case is to be cut to its proper length, so as to rise a little above the mould, and allowing half a diameter from the choak to the edge of the mouth: the cutting the case to its proper length will be best effected while on the former, which when done, the former is to be pulled out, and the case being put again into the mould, having the foot and piercer properly fixed to it, must be driven down upon the piercer with the long perforated rammer, so as to make the contraction of the proper size.
_Filling and ramming the cases._--In this part of the operation, we must be as careful as in any of the past; for if any inequality exist in the density of the composition, produced by inattention to the ramming, the Rockets will not rise with an uniform motion, nor ascend to their proper height; but on the contrary, will observe a very erratic motion, and be deflected by every renitent particle they may meet with in their course.
To avoid this disappointment, and to render more certain the ascent of the Rockets, the following directions must be attended to:--
1. Your composition must not be too dry, or it will be liable to disperse, and fly about in a kind of subtile meal or dust, while you are driving it; but if you moisten it a little just to destroy its dusty nature with some of the liquid mentioned in the early part of our MANUAL, it will cause it to collect, and be more solidly compressed in the case of the Rocket.
2. No more of the composition should be put into the case at each ramming, than will cause it to rise one half of its interior diameter; and the filling must be thus gradually continued, till the charge rises exactly one diameter above the piercer.
3. Much has been said by writers on Pyrotechny respecting the number of blows proper to be given to the rammer, to each ladle full of composition, (a piece of copper made into the form of a scoop, and holding the proper quantity answers best for a ladle;) some have assigned to Rockets of four ounces sixteen strokes with the mallet, to those of one pound twenty-eight strokes, and so increasing the number of strokes by six, to every pound; but in our opinion these rules are more ridiculous than useful; for the same mallet, by possessing a different momentum, might produce an effect, at one time _double_, _treble_, or perhaps _less_, than at another. It is therefore impossible to assign any determinate number of strokes, to be given at each ramming; the only certain rule is, that the composition ought to be driven till it becomes quite firm and compact, and that its density (as near as possible) be the same throughout the whole of the charge. If the rules for the number of strokes assist in any way to impart this property to the charge, we have not the least wish to depreciate them.
4. In ramming, it is best to keep the rammer constantly turning round in the case, and in using the perforated rammer, be sure to knock out the composition from the hollow every ramming, or it will be liable to be split by the piercer.
5. Invert the cartridge at the close of each ramming, in order that the loose particles of the composition which are not compressed may escape, for if suffered to remain in they would prove injurious to the article.
6. Rockets should always be rammed on a solid block, or on a post set fast into the earth; their ramming cannot be properly effected on any table whatever.
7. Rockets must be rammed with mallets somewhat proportionate to their magnitude; that is, if a Rocket of one pound can be properly rammed with a mallet weighing two pounds, a Rocket of two pounds should be rammed with a mallet of four pounds, or nearly in that proportion. Rockets above eight pounds cannot well be rammed by hand; but when wanted of such magnitude they must be rammed by means of a machine similar to that used for driving piles into the earth; Rockets of large dimensions, whose cases are made of a strong material, properly prepared, may be conveniently rammed without being placed in a cylinder, which will be an advantage, as so many moulds will not be required. But for this method of ramming we must be prepared with some _brass_ or _iron_ nipples, of the size proportionate to the Rocket, which should be made to screw into one part of the driving block; and for the purpose of making the case more firm upon it while ramming, a stake or upright piece must be made firm to the block, standing up the height of the case, and at a suitable distance from the nipple; the side of this stake next the case must be fluted out so that the case will fit closely into it; on the opposite side of the case must be applied a loose piece fluted in a similar manner; then with a cord tie the case and two half moulds (which these two pieces will nearly form) together, and the case will be ready for filling. The cartridges being filled to the proper height, i. e. one diameter above the piercer, if the Rocket is to be without furniture, separate with a wire of any kind, half the folds of the paper which remains above, and having turned them back on the composition, press them down with the rod and mallet in order to make them smooth and even. Then pierce three or four holes in the folded paper by means of a piercer, which must be made to penetrate to the composition of the Rocket. These holes are for the purpose of forming 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 small Rockets this vacuity is filled with granulated powder, (which serves to let them off when their charge is consumed;) they are then covered with paper, and either pinched quite close by means of the choaking apparatus, or crowned with a little conical cap, which will cause it to ascend to a greater height. If one hole only is made in the centre of the folded paper, it will answer the purpose of three or four, taking care that it be as straight as possible, and about one-fourth the diameter of the calibre of the case; in this hole a little of the composition of the rocket should be put that the fire may not fail to be communicated:--a Rocket finished after this manner is represented in fig. 23. In Rockets of larger dimensions, instead of granulated powder, the coffins, or pot containing the stars, serpents, petards, &c. are adapted to the top of the case: the petard is a small round box of tin-plate united to the diameter of the case, and filled with fine gunpowder; it is deposited on the composition after the ramming, and the remaining paper folded down over it to keep it secure; the petard produces its effect when the Rocket is in the air and the composition is consumed. The other furniture is attached to the Rocket by adjusting to its head an empty pot or cartridge of larger dimensions than itself, in order that it may contain the various appendages, which are to render it so superior to the others, in the beauty and splendour of its emication.
_Preparing and fixing the pots to the head of Rockets._--Rockets which have furniture attached to them, are rammed somewhat different to those which are without any appendages, but the difference is only in this particular; when rammed one diameter above the piercer, instead of turning down upon the composition the inner folds of the paper, ram on to the composition one-third diameter of pure dry clay, and through the centre of it bore a hole (about one fourth diameter) and put into it a little of the composition, in order that the charge may communicate with the powder, &c. in the head.
The head of a Rocket must be about two diameters high, and one diameter one-sixth wide. The case must be rolled upon a former, having at the end opposite the handle a square indent, corresponding to the thickness and width of the collar, as is represented in fig. 9. Fig. 10 is the collar, turned out of lime-tree, poplar, or any light wood; its exterior diameter must be equal to the interior diameter of the case, or the same as the former, and its interior diameter, not quite so wide as the interior diameter of the Rocket case; in thickness it should be equal to one-sixth diameter, and round its edge should be a groove, so that the case for the head may be firmly fixed to it. To form the case, three or four rounds of paper or pasteboard must be rolled round the former, with the collar on, and well secured by paste; the end over the collar is to be pinched by means of the cord and choaking apparatus into the groove in its edge, and afterwards secured by some twine tied closely round it. The purpose of the collar is to keep the head in a proper form, to make a bottom for the filling of it, and to make it more firm and better connected to the case. When the head is thus made, being properly fixed to its collar, it is to be made fast (by means of ordinary glue) to the top end of the Rocket, in which operation the reason and use of making the interior diameter of the collar less than the exterior of the cartridge will plainly appear; it will be evident that the cartridge of the Rocket will be too large for the former, without some alteration, which alteration must be made in the following manner:--mark round the diameter of the Rocket the proper distance from the top, or so that the collar is about its thickness above the ramming of the cartridge, and take off about three rounds of paper, which will leave a shoulder to the case, on which the collar may rest, and be made quite secure by pasting paper round their joinings beneath.
In the manner of charging the pot above described we must almost leave the Tyro to himself, it depending chiefly on his taste and wishes, as he may either fill it with Serpents, Crackers, Saucissons, Marroons, Stars, Sparks, Showers of Fire, or any thing to which its capacity is adapted; it will be best however to unite several of the different articles in one head that the beauty of the exhibition may be increased.
In the filling of the head, the following directions must be observed:--
The paper over the charge of the Rocket must be pierced, and a little of the same composition shook into the holes; then arrange in the head the different articles with which it is to be charged, but take particular care that the quantity introduced is not heavier than the body of the Rocket. When the head is loaded, a few balls of paper should be put round the different articles so as to keep them properly in their places. At the top part of each head put a ladle full of meal powder, (the ladle you use in filling the cases is meant,) which will be enough to burst the head and disperse the stars or whatever it contains.
In loading the head with cases of any kind be sure to place their mouths downward without any touch-paper; the head may be nearly filled, with the articles they are loaded with, after which paste on the top of them a piece of ordinary paper; and over this must be placed a cone of the same material, made upon the conical former, fig. 8. To make the caps, describe (with a pair of compasses opened to the length of the former) a circle, which being divided into two equal parts, will make two caps; over which must be pasted another similar cap, but of larger dimensions, so that it extend below the bottom of the inner one; so that being just clipped a little and applied to the head, it may be pasted to it, which will be a sufficient fastening.
The last business in the manufacturing of a Rocket is that of fixing it to its rod, which we shall now describe, as much nicety being required in it as in any of the past operations.
The rod should be made of a clean piece of fir, perfectly straight, and its dimensions regulated by the size of the Rocket, in such manner, that when suspended on the edge of a knife or wire, about an inch from the choak, the rod and Rocket shall be in equilibrium. The following Table has been computed for the lengths and proportions of the rod, and may be relied on:--
Weight |[12]Length of | Thickness and | Square of the | the Rods. | Width at top. | at Rockets. | | | Bottom. ---------+--------------+---------------+-------- lb. oz. | Feet. Inches.| Inches. | Inches. ---------+--------------+---------------+-------- 6 0 | 14 2 | 1½ by 1⅞ | 0 ¾ 5 0 | 13 8 | 1¼ -- 1¾ | 0 ⅜ 4 0 | 12 9 | 1¼ -- 1½ | 0 ⅝ 3 0 | 10 8 | 1-1/7 -- 1⅛ | 0 ½ 2 0 | 9 3 | 1⅛ -- 1 | 0 ½ 1 0 | 7 10 | ¾ -- ⅞ | 0 ⅜ 0 8 | 6 6 | ½ -- ¾ | 0 ¼ 0 4 | 5 2 | ⅜ -- ⅝ | 0 ¼ 0 2 | 4 1 | 3/10 -- ½ | 0 3/16 0 1 | 3 5 | ¼ -- ⅜ | 0 3/16 0 ½ | 2 3 | 3/16 -- ¼ | 0 ⅛ 0 ¼ | 1 10 | ⅛ -- 3/16 | 0 ⅛
By the above Table we find that a Rocket of six pounds will require a rod 14 feet 2 inches long, which being properly planed to the other dimensions, is to be hollowed out on the side next the Rocket; and on the side opposite, two notches must be made, one about an inch from the end, (the rod going up to the under side of the head,) and the other opposite the choak of the Rocket, in order to admit the string with which it is tied, and that it may be more firmly attached to the rod. Although the foregoing Table has been carefully computed, and that from experiment, yet it will not be well to depend entirely upon it, but rather to produce an equilibrium between the rod and Rocket, (by means of a lighter or heavier rod,) when suspended as before. It is of consequence that this is attended to; for without a proper equilibrium, the Rocket will ascend in an oblique direction, and fall to the ground long before its composition is consumed.
In firing these Rockets, two fixed rings must be screwed fast into an upright post, and exactly opposite to each other, the upper one near the top of the post, and the other about two-thirds the length of the rod downwards; the rod must be passed down them, and the mouth resting lightly on the upper one, the Rocket must be quite free from the post. When thus fixed and a lighted port-fire is applied to its mouth, it will (if properly made,) immediately ascend with a prodigious velocity, and having attained its greatest height will there burst and discharge its luminous beauties in the atmosphere. A Rocket with its head and rod complete is represented at fig. 22.
THE COMPOSITION FOR ROCKETS.
As we wish to complete the article Rockets in this section, we shall here give the composition proper for filling them, which must vary in the proportion of its ingredients according to the size of the Rocket; this variation in the strength of the composition, is positively necessary; for that which is proper for small Rockets, would be much too strong for large ones, therefore its strength should increase nearly as the dimensions of the Rockets decrease.
1. For one and two ounce Rockets, the ingredients for a proper composition should be--
One pound of gunpowder, two ounces of soft charcoal, and one ounce and a-half of salt-petre.
2. Two to three ounce Rockets:--
To four ounces of gunpowder, add one ounce of charcoal, or to nine ounces of powder, add two ounces of salt-petre.
3. Four ounce Rockets:--
To one pound of gunpowder, add four ounces of salt-petre, and one ounce of charcoal. The composition will be much stronger if in this proportion:--To ten ounces of powder, add three ounces and a-half of salt-petre, and three ounces of charcoal.
4. Five or six ounce Rockets:--
Gunpowder two pound five ounces, salt-petre half-a-pound, sulphur two ounces, charcoal six ounces, and iron-filings two ounces.
5. Seven or eight ounce Rockets:--
Gunpowder seventeen ounces, salt-petre four ounces, sulphur three ounces.
6. Eight to ten ounce Rockets:--
Gunpowder two pounds five ounces, salt-petre eight ounces, sulphur two ounces, charcoal seven ounces, iron-filings three ounces.
7. Ten or twelve ounce Rockets:--
Gunpowder one pound one ounce, salt-petre four ounces, sulphur three and a-half ounces, charcoal one ounce.