sible. As fast as the workman finishes | this surface, another follows him with a pailful of the roughcast, with which he bespatters the new plastering, so that the whole dries together. The roughcast is a composition of small gravel, finely washed, to free it from all earthy particles, and mixed with pure lime and water in a state of semi-fluid consistency. It is thrown from the pail upon the wall, with a wooden float, about 5 or 6 inches long, and as many wide, formed of -inch deal, and fitted with a round deal handle. With this tool the plasterer throws on the roughcast with his right hand, while in | his left he holds a common whitewashers' | brush dipped in the roughcast, with which he brushes and colours the mortar and the roughcast already spread, to give them, when finished, a uniform colour and appearance.

Builders' Waterproof Mastic Cement.-1. 5 parts river sand; 5, ground stone lime; 10, red-lead, in powder. 2. 10, sand; 5, powdered whiting; 1, powdered red-lead. 3. 100, sand; 25, plaster of Paris; 10, red-lead; 5, yellow ochre, all in powder. Each of these cements must be mixed with boiled oil.

Concrete for Foundations. 5 parts gravel and sand to 1 part freshburned stone lime, ground to powder, without slaking, and measured dry. Well turn and shovel together, with sufficient water to slack the lime into the state of very thick mortar. Chips and small pieces of stone may be added with advantage.

CONCRETE FOR MASONRY.-1. Screened sand, 9 parts by measure; slaked lime, 7; forge ashes, 1; puzzolana, 1. 2. 1, slaked lime; 1, sea sand;, furnace ashes.

CONCRETE FOR BRICKWORK.-Slaked lime, 7 parts by measure; sand, 12 parts.

Hydraulic Mortars.-i. 2 parts burnt clay; 1 part blue lias lime, pulverized and ground together between rollers. Use immediately 2. 2 parts fresh stone lime; 3, wood ashes, mixed as for common mortar, but must lie until cold and be beaten several times before

being used. 3. 4 parts blue lias lime. 6, river sand; 1, puzzolana; 1, calcined ironstone.

BUILDERS' MORTAR.-1. 3 parts by measure of good sharp sand to 2 parts grey stone lime, mixed with water, or 2 of sand to 1 chalk lime. Sharp road scrapings may be used instead of sand; and where taken from roads kept in order with flint or gravel, form a very good mortar. 2. 1 part grey stone lime to 3 river-sand coarse mortar. 1, stone lime; 4, coarse gravelly sand. 4. 1, lime; 2, river sand; 1, blacksmiths' ashes. 5. 1, lime; 2, sand; 1, rough ground coke.

Composition

3.

for Picture Frames.-1. To make compo ornaments for picture frames: Boil 7 lbs. of the best glue in 7 half-pints of water, melt 3 lbs. of white resin in 3 pints of raw linseed oil; when the ingredients are well boiled put them into a large vessel and simmer them for half an hour, stirring the mixture and taking care that it does not boil over. When

this is done, pour the mixture into a large quantity of whiting, previously rolled and sifted very fine, mix it to the consistence of dough, and it is ready for use. 2. Dissolve lb. of glue in 1 gall. of water; in another kettle boil together 2 lbs of resin, 1 gill of Venice turpentine, and 1 pint of linseed oil; mix altogether in one kettle, and continue to boil and stir them together till the water has evaporated from the other ingredients; then add finely-pulverized whiting till the mass is brought to the consistence of soft putty. This composition will be hard when cold, but being warmed, it may be moulded to any shape by carved stamps or prints, and the moulded figures will soon become dry and hard, and will retain their shape and formi permanently.

Firework Making.-The three prime materials of the art of pyrotechny are nitre, sulphur, and charcoal, along with filings of iron, steel, copper, zinc, and resin, camphor, lycopodium, &c. Gunpowder is used either in grain, half crushed or finely ground, for different purposes. The longer the iron filings.

the brighter red and white sparks they give; those being preferred which are made with a coarse file and quite free from rust. Steel filings and cast-iron borings contain carbon, and afford a very brilliant fire, with wavy radiations. Copper filings give a greenish tint to flame; those of zinc, a fine blue colour; the sulphuret of antimony gives a less greenish blue than zinc, but with much smoke; amber affords a yellow fire as well as colophony and common salt, but the last must be very dry. Lampblack produces a very red colour with gunpowder, and a pink with nitre in excess. It serves for making golden showers. The yellow sand, or glistening mica, communicates to fireworks golden radiations. Verdigris imparts a pale green; sulphate of copper and sal ammoniac, a palm-tree green. Camphor yields a very white flame and aromatic fumes, which mask the bad smell of other substances. Benzoin and storax are used also on account of their agreeable odour. Lycopodium burns with a rose colour and a magnificent flame.

Iron tools must never be used in making fireworks of any kind, as they are liable to throw out sparks when striking against a hard stony substance, besides which the sulphur used would injure the iron. Brass tools may be used, but copper tools are preferable.

ROCKETS. Of all fireworks, rockets are among the most noble and effective. The ingredients for these, the apparatus employed, and the detail of the manufacture of them may be considered the toundation of all fireworks, and to make thera well involves the same principles, and requires the same caution, as in making all others.

Size of Rockets.-The size of rockets is indicated by ounces or pounds; thus we say, an eight-ounce rocket, a pound rocket, and so on; by this expression it is not meant that the rockets weigh so much as their name indicates, but that the bore or cavity will just suffer a leaden bullet of that weight to pass down them. For example, a pound rocket will admit a leaden bullet that weighs a pound. Rockets may be made

of any size from 1 oz. up to 50 or more pounds.

Rocket Cases or Cartridges. These may be made of any kind of stiff thick paper, either cartridge paper or what is equally good and much cheaper, uamely, common bag-cap paper. To roll up the cases you must have a smooth round ruler, or, as it is called, a former, exactly the size of the cavity of the rocket, and 10 or 12 times as long. Then lay a sheet of the paper upon a slab of slate, marble, or glass, and paste 4 or 5 in. along the end of it, leaving the rest of the sheet of paper without paste; then roll it smoothly over the former, dry end first, until the whole is rolled up, when of course the paste will stick and a thin case be formed. Keep rolling it along the slab with the hands, in the same way as a rolling-pin is used, for two or three minutes, until the various folds of the paper set close and tight to each other; then put on another sheet in the same way, and so on, till the case is thick enough. This is known by the measurement across it. If the former without the case measures five parts, when the case is upon it they must measure together eight parts. That is, the paper must be rolled on till it forms a case, the thickness of the sides of which are a trifle more than one-third of the thickness of the former. The length of the rocket case, and consequently the width that the sheets of brown paper are to be cut before pasting. varies with the size of the rockets; in small rockets the length of the case may be six times the diameter, in larger rockets four or five times is sufficient. When the case has proceeded thus far, it is to be choked while yet damp, that is, to be contracted in diameter near one end, and for this purpose a simple contrivance is requisite, called a choking cord, and also the former is made with a hole drilled at one end, and a second joint made to fit on by means of a wire projecting at one end of it, and which fits into the hole of the former, Fig. 10. To choke the case, draw the former partly out, until you can see about 1 inch of the inner cavity of the

about an inch within the case, leaving a space of about an inch between the two joints occupied by the wire alone. Then going to an apparatus similar to that shown in Fig. 11, turn the cord once round the case where the cavity is, put the foot upon the treadle, which tightens the cord and squeezes the paper case at the point required, and that it may squeeze it equally and neatly on all sides the case should be held in the hands and moved up and down upon the cord until the operator sees that it is sufficiently and properly compressed. Let it be observed that although the choking apparatus used by the firework maker is represented and above alluded | to, yet to the amateur it is by no means necessary. What will do quite as well is a thin cord fastened at one end to a staple in the wall, and by the other tied round the waist of the operator; as he may lean back, of course the cord would be tightened, and the desired purpose accomplished. When the case is sufficiently compressed it is to be tied with two or three turns of strong string. The case is now complete, except that the part of it where it is choked is perhaps rather rough and uneven inside; this must be compressed down, for much of the effect of the rocket will depend upon the perfect regularity on this part, as it is through the hole left by the wire in the middle of the choke that the fire 18 afterwards to issue. To compress this part properly a mould is necessary.

this short cylinder has a shoulder above, and terminates in a round top. Out of the middle of the top is a tapering thick brass wire, projecting some inches upwards, as is seen in Fig. 13. The whole is so arranged, that when one of the newlymade cases is put upon the wire and forced down, the wire fills up the chokehole, the round top fits into the small parts of the case below the choke, the shoulder of the cylinder bears the extreme end of the case, and the short cylinder agrees in size with the outsides of the case. There fits over this (case and all) a strong wooden or metal tube; so that it is seen that there is no cavity anywhere, except the inside of the rocket case, and even in this a thick wire runs up to nearly the top of that part of the case where the composition is rammed, or nearly of the whole case from the choke upwards. The wire above mentioned is called the FIG. 14. piercer. All rockets must be placed in the mould to be filled, as well as to smooth and consolidate the part choked. With the mould are used rammers, Fig. 14, formed of hard wood, of the shape of a popgun-stick; these rammers being rather less than the diameter of the cavity, and having a hole bored up their centre, in order to admit the piercer. It is evident that

there must be a complete mould, piercer, and one or more rammers for every size rocket. But to proceed with the string; put it in the mould and the rammer down into it, and give this, the latter, a blow or two with a mallet, which driving it down while yet damp with the paste, will render the whole compact and smooth; and the case being taken out may be placed in an oven, or near the fire, to dry. If it is desired to ornament it in any way or cover it with white paper, this must be done before choking.

Charging Rockets. The next process after drying the case is to charge them with the requisite composition. Put the cases in the mould with the piercer in it and put enough composition in to fill about 1 inch of the case; then, taking the rammer, ram it down with three or four strong blows with a mallet. Then put in the same quantity of composition again and ram that down in the same manner, and so on till the case is filled to the top of the piercer and one diameter above it. Then separate some of the central folds of the paper which it has been observed is not parted, and turn them down upon the composition, ramming them down hard upon it, or, what will do as well, put in a piece of paper as wadding. When this is rammed down, and firm, bore with a brass bradawl three or four holes through it. These holes serve to make the requisite communication between two parts of the rocket. Or, having charged the case, take some common potters' clay in dry powder, and ram it down hard upon the top of the composition, then bore a hole through it about of an inch diameter, which will allow of the necessary connection between the rammed composition and the stars in the head or pot of the rocket.

Priming Rockets.-The rocket is now supposed to be closed at one end. It only requires to be primed at the other end, and that it will be observed is the end which was choked, which is still open, and which has a hole passing up it which the piercer occupied. To prime it fill up the hole with loose gunpowder made into a stiff paste with very weak

gum water, and paste a piece of touchpaper over it.

Rocket Pot or Head.-The rocket being then charged, the head or pot must be fixed. The pot is a paper case made upon a wooden former turned cylindrical, about 4 inches in length, and a shade larger in diameter than the exterior of the rocket case. Take some thick brown paper and cut it in strips large enough to go twice round the former, paste and roll as for the case, then pinch one end, and a cylinder of paper will be thus made which should fit nicely over the clay end of the rocket. There should now be fixed upon the pinched end a conical cap, made upon a former of like shape, Fig. 15. This cap by cleaving the air assists the rocket in rising into it. FIG. 15.

Loading Rockets. - The loading the pots with stars is all that now remains to be done to complete the rocket. A -lb. rocket should carry about 1 oz. of stars. Weigh out the proper quantity of stars and mix them with meal powder, 6 parts, to fine charcoal 1 part, fill up the pot and glue it securely over the clay or upper end of the rocket case.

Rocket Sticks.-Next fasten the stick to the rocket by two strings, as seen in any of the figures 16 to 19.-The sticks

FIG. 19.

FIG. 20.

and the larger ones pantile laths; but any slip of deal will answer the purpose. 2-lb. rockets require sticks 9 feet 4 inches long, 1 inch square at top, and rather more than inch square at bottom. 1-lb. rocket sticks are 8 feet 2 inches long, inch square at top and 4 inch at bottom. 8-oz. rocket sticks are 6 feet 2 inches long, inch square at top, and inch at bottom. 4-oz. rocket sticks are 5 feet 3 inches long, inch by inch at top, and inch square at bottom. 2-oz. rocket sticks are 5 feet 1 inch long, inch by inch at top, inch at bottom. 1-oz. rocket sticks 3 feet 6 inches long, and so on for other various sizes. The weight and the length of the stick must be such, as that when tied on, the rocket shall balance on the finger, at a point about 1 inch from the part choked.

ROCKET COMPOSITIONS. The brilliancy of the rocket depends upon the composition in the cases, and great care is required in the mixture of the ingredients, which should be well dried and carefully sifted through a hair sieve before mixing. For a 4-lb. rocket, to 12 oz. of saltpetre add 6 of charcoal and 4 of sulphur; or for signal rockets the proportions are, saltpetre, 4 lbs. ; dogwood charcoal, 1 lb. 12 oz. ; sublimed sulphur, 1 lb. Powder separately, and mix with

increases the rapidity of the fire, whilst sulphur retards it, and the charcoal emits those volumes of sparks which form the golden train of an ascending rocket. Rockets are primed with mealed powder and spirits of wine.

PYROTECHNIC AND ROCKET STARS.The stars that are used as decorations to the different species of fireworks are of various kinds, sizes, and shapes, according to the purpose for which they are intended.

The ordinary rocket stars, which are called "brilliant" or "bright," are made in small cubes. Their composition is moistened with gum water, and while moist flattened to the thickness required. It is then scored or cut across with a knife, and allowed to dry. When dry it can be easily broken up into cubes at the places where it was divided by the knife. Tailed stars are also made in the same way and of the same size.

Roman-candle stars are small cylinders of composition made of a size proportioned to that of the case out of which they are to be thrown.

Coloured rocket stars are made by driving the coloured composition, slightly moistened, into small cases, which go under the name of pill-box cases. If the star is to consist of one colour only, these pill-boxes are open at both ends, and a piece of quick-match is placed between the composition and the inside of the pill-box, and allowed to project about an inch beyond each end of it. When fired, these stars burn at both ends at the same time, and so produce a great amount of fire in proportion to their size.

If it is required to make stars consisting of more than one colour (in which case they are called "changeable stars") the pill-boxes are left open at one end only. The composition is thus prevented from burning at more than one of its surfaces at a time. These stars generally contain two colours; the pill-boxes are half-filled with one coloured composition and the remaining space filled with another. These changeable stars burn much longer than the others. and there