black, and green, in the desired proportion; then with a quill draw lines through the colours; after which throw on a greater or less quantity of blue, green, pink, or purple, much diluted, and containing plenty of gall and turpentine. 4. Throw on very fine red for veins; then plenty of the turpentine blue. If the colours are good this produces a handsome pattern in a short time.

5. Throw on some dark blue mixed with turpentine, and take this up with a paper previously stained of a yellow, light blue, red, pink, or green colour. To obtain a good green for this purpose, boil French berries in water, add a little spirit or liquid blue, and carefully brush over the paper, which must be good and well sized, with this mixture. When the colours become too thick for use, add fresh ground colour with water and a little gall to them, and stir them up well. Be particular in getting good turpentine. When the solution of gum gets dirtied, throw it away and make a fresh one. The neatest and most convenient method of marbling the edges of books, is to dip one volume at a time, doing the ends first, and throwing back the boards to do the fore-edge; observing to hold the book tight with both hands, and not to dip deeper than the surface, to prevent the solution from spoiling the book. It is the safest way to tie the book between boards before dipping; and, for the sake of convenience and economy, when only a few books are to be marbled, a small trough should be used. Marbled paper is glazed by a machine similar to that with which cottons are glazed. But a machine of this kind would only be required by those who marble very largely. Book edges are polished by the agate burnisher, and so might small pieces of paper be polished, which were required for any particular purpose. Good common pressing, or hot-pressing, might serve as well as glazing. For any fancy work it would have a fine effect to varnish the marble paper after it had been put to its destined purpose and had become dry. Paste and all moisture chase all the glaze away. The

application of a coat of varnish subsequent to the application of paste would double the beauty of the best marble paper, and much improve the common kind, at a trifling expense.

Sprinkling the Edges of Books.-Take an old toothbrush and dip it into a coloured ink; shake off the superfluous ink, that the sparks formed may not be too large, and draw an old comb through it in such a manner as to make the ink fly off in sparks over the edges of the book. The following are a few coloured inks;-Red; lb. of the best logwood is boiled with 1 oz. of pounded alum, and the same quantity of cream of tartar, with half the quantity of water, and, while the preparation is still warm, 1 oz. sugar and 1 oz. gum arabic are dissolved in it. Blue; solution of indigo with pieces of alumina, and mixed with gum, forms a blue ink. Green; this is obtained from verdigris, distilled with vinegar, and mixed with a little gum. Yellow; saffron, alum, and gum water, form a yellow.

Polishing Metals.-The polishing of metals differs according to their kind, but there are some general principles common to all, of which it may be useful to have a clear idea. All polishing is begun in the first instance by rubbing down the surface by some hard substance that will produce a number of scratches in all directions, the level of which is nearly the same, and which obliterate the marks of the file, scraper, or turning tool that has been first employed. For this purpose coarse emery is used, or pumice and water, or sand and water, applied upon a piece of soft wood, or of felt, skin, or similar material. When the first coarse marks have been thus removed, next proceed to remove the marks left by the pumicestone by finely-powdered pumice-stone ground up with olive oil, or by finer emery and oil. In some cases certain polishing stones are employed, as a kind of hard slate used with water. To proceed with the polishing, still finer powders are used, such as tripoli and rottenstone. Putty of tin and crocus martis are also used for high degrees of polish.

But the whole process consists merely in removing coarse scratches by substituting those which are finer and finer, until they are no longer visible to the naked eye; and even long after that, if the surface is examined by a microscope, it will be seen that what appeared without any scratches is covered all over with an infinity of them, but so minute that they require a high magnifier to be discovered. It is evident that great care must be taken to have the last polishing material uniformly fine, for a single grain or two of any coarse substance mixed with it will produce some visible scratches instead of a perfectly polished surface.

Polishing Bar Iron and Steel.-Take an ordinary bar of malleable iron in its usual merchantable state, remove the oxide from its surface by the application of diluted sulphuric acid, after which wash the bar in an alkaline solution, then cover the entire bar with oil or petroleum. The bar is then ready for the chief process. A muffle furnace is so prepared that a uniform, or nearly uniform, heat can be maintained within it, and in this furnace the bar is placed. Care must be taken that too great a heat is not imparted to it, for on this depends the success of the operation. When the bar approaches a red heat, and when the redness is just perceptible, it is a certain indication that the proper degree of heat has been attained. The bar is then at once to be removed, and passed through the finishing rolls five or six times, when it will be found to have a dark polished uniform surface, and the appearance of Russian sheet iron.

Friction Polish.-A good polish for iron or steel rotating in the lathe, is made of fine emery and oil; which is applied by lead or wood grinders, screwed together. Three very good oils for lubrication are olive oil, sperm, and neat's foot.

Polishing Steel.-1. Use bell-metal polishers for arbors, having first brought up the surface with oilstone dust and oil and soft steel polishers; for flat pieces use a piece of glass for the oil

stone dust, and a bell-metal block for the sharp red stuff, and a white metal block for the fine red stuff. The polishing stuff must be well mixed up and kept very clean; the polishers and blocks must be filed to clean off the old stuff, and then rubbed over with soft bread; put only a little red stuff on the block and keep working it until it is quite dry, the piece will then leave the block quite clean; use bread to clean off the surplus red stuff before using the brush. If the piece is scratched, put on some more red stuff, which must not be too wet, and try again. 2. The polish on flat steel pieces in fine watchwork is produced with oilstone dust, burnt Turkey stone, and a steel polisher, soft steel, bell-metal, and sharp stuff, grain tin and glossing stuff. The metals are squared with a file, and vary in shape according to the work in hand. 3. Get an 18-gallon barrel and put an iron spindle through the two ends; mount it on trestles in the same way as a butter churn, with a winch to turn it by; cut out a hole in the side by which to introduce the articles to be polished; have a tight-fitting cover to the hole; procure some worn-out casting pots or crucibles, such as used by casters, and pound them in an iron mortar, until fine enough to pass through a sieve which will not allow the steel articles to pass through. Put equal quantities of this grit and of the articles in the barrel; fasten on the cover, and turn the barrel for about an hour, at the rate of about 50 turns a minute; take all out of the barrel and sift out the grit. If a finer polish than this is required, put them through another turning, substituting for the grit small scraps of leather, called mosings, which can be procured from the currier's, and emery flour. Do not more than half fill the barrel.

Brass Polishing.-1. Brass may be polished without a burnisher, by using an exceedingly fine cut file, and fine emery cloth. 2. Small articles to be polished should be shaken by themselves for a short time; then some greasy parings of leather should be put in the band with them. After they

have been shaken smooth, the greasy leather parings should be removed and clean ones put in, and the shaking continued until the articles are sufficiently bright. 3. When the brass is made smooth by turning or filing with a very fine file, it may be rubbed with a smooth fine-grained stone, or with charcoal and water. When it is made quite smooth and free from scratches it may be polished with rotten-stone and oil, alcohol, or spirits of turpentine.

To Polish German Silver.-Take 1 lb. peroxide of iron, pure, and put half of it into a wash-basin, pouring on water, and keeping it stirred until the basin is nearly full. While the water and crocus is in slow motion, pour off, leaving grit at the bottom. Repeat this a second time, pouring off with another basin. Cleanse out grit, and do the same with the other half. When the second lot is poured off, the crocus in the first will have settled to the bottom; pour off the water gently, take out the powder, and dry it, and put both when washed clear of grit, and dried, into a box into which dust cannot get. If the silver work is very dirty, rub the mixture of powder and oil on with the fingers, and then it will be known if any grit is on the work. If the work is not very black, take a piece of soft chamois leather, and rub some dry crocus on, and when well rubbed, shake out the leather, and let the powder fall off that is not used, or rub it off with a brush. Do not put down the leather in the dust.

POLISHING WHEELS.-Emery Wheels. -1. Can be made with shellac powdered fine, and a small portion of rosin, a piece about the size of a walnut to an ounce of shellac, and a piece of old vulcanized india-rubber about the same size, which gives it toughness. Shellac about 1 oz. to 1 lb. of emery, well melt, and stir about in a small frying pan; well mix the powders before applying heat. Be careful not to burn it, or get grease in it; have a ring of iron and a piece of plate iron prepared with black-lead and beer pretty thick; place the ring upon the plate and make a mould, turn the stuff into it,

and well ram down evenly; put on one side to cool; when cold, turn out and chuck in lathe, and with a piece of redhot iron bore a hole for spindle; after spindled put between centres, and trice up with hot iron. Very good grind stones may be made with silver-sand mixed with powdered glass, and it is necessary to have some body besides shellac for coarse emery to form a body to bed the grains in. Emery dust from grinding glass, and Turkey stone slips, and slate, may be used as a substituto for the flour. 2. The best emery wheels are formed of clean emery compounded with just a sufficient amount of boiled linseed oil, the mixture being agitated for a sufficient period under ex posure to a considerable temperature and a free access of atmospheric air, or some still more powerful oxidizing agent; it assumes the necessary de gree of tenacity, and whilst warm, being exposed to hydraulic pressure in a suitable mould, and subsequent drying in a stove, the emery wheel is complete.

Artificial Grindstone.. Washed silicious sand 3 parts, shellac 1 part; melt the lac, and mould in the sand, while warm. Emery may be substituted for sand.

cutlery.

Used for razors and fine

Making Glaze Wheels for Finishing Steel.-For hollow finishing the following wheels are required;-A mahogany wheel for rough glazing. A mahogany wheel for smooth glazing. A lead wheel, or lap. For flat finishing: A buff wheel for rough. A buff wheel for smooth. A buff wheel for finishing. Lastly, a polisher. To make the glaze wheels: Get the spindles, and point them on each end; then get a block of beech and wedge it on the steel at one end with iron wedges, and turn it for the pulley for the band to run on. Take two pieces of flat mahogany and glue and screw them together, so that the grain of one piece crosses the other, to prevent warp ing. Let it get thoroughly dry, and wedge it on the spindle and turn it true The lead wheel is made the same way but made wider, and a groove turned in

the edge. Then the wheel is put into sand, and a ring of lead run round the edge; it is then turned true. To make the buff wheels, proceed as with the glaze; but to save expense, pine or deal wood will do as well as mahogany, only leave it about double the width of the glaze, which is about inch wide, by 12 inches or 14 inches across. The buff wheels are covered with glue, and then the leather is tacked on with tacks driven in about half-way, so that they may be easily drawn out again. The leather is then turned true. The polisher is made the same way, but the size of the polisher must be a little less than any of the other wheels, say, about an inch. The buff wheels are dressed by laying on a fine thin coat of clear glue, and rolling them round No. 1, in superfine corn emery; No. 2, in smooth emery; No. 3, by making a cake of equal parts of mutton suet, beeswax, and washed emery; then it is held on the wheel while it is going round. The glaze wheels are dressed while using, by mixing a little of the emery with oil, and putting it on the wheel with a stick or the finger. The leather of the polisher is not covered with glue, but dressed with a mixture of crocus and water, not oil. Care must be taken to keep each wheel and substance to themselves, and the work must be carefully wiped after each operation, and cleanliness must be studied above all things in using the polisher, as the slighest grease getting on it stops the polishing.

POLISHING MATERIALS.-Rouge.-The rouge used by machinists, watchmakers, and jewellers is a mineral substance. In its preparation crystals of sulphate of ron, commonly known as copperas, are heated in iron pots, by which the sulphuric acid is expelled and the oxide of iron remains. Those portions least calcined, when ground, are used for polishing gold and silver. These are of a bright crimson colour. The darker and more calcined portions are known as crocus, and are used for polishing brass and steel. For the finishing process of the specula of telescopes, usually made of iron or of steel, crocus is invaluable;

it gives a splendid polish. Others prefer for the production of rouge the peroxide of iron precipitated by ammonia from a dilute solution of sulphate of iron, which is washed, compressed until dry, then exposed to a low red heat and ground to powder.

Crocus. Put tin, as pure as possible, into a glass vessel - -a wineglass does very well when making small quantities

and pour in sufficient nitric acid to cover it. Great heat is evolved, and care must be taken not to inhale the fumes, as they are poisonous. When there is nothing left but a white powder, it should be heated in a Hessian crucible, to drive off the nitric acid. Crocus, mixed with a little linseed oil, makes a hard and useful cement.

Powders for Cleaning Plate.-1. Take equal parts of precipitated subcarbonate of iron, and prepared chalk. 2. An impalpable rouge may be prepared by calcinating the oxalate of iron. 3. Take quicksilver with chalk, an oz., and prepared chalk 2 oz., mix them. When used, add a small quantity of spirit of wine, and rub with chamois leather; or, put sulphate of iron into a large tobacco pipe, and place it in a fire for a quarter of an hour, mix with a small quantity of powdered chalk. This powder should be used dry.

Jewellers' Rouge.-A rouge suitable for fine work may be made by decomposing a solution of sulphate of iron with oxalic acid also in solution; a precipitate of oxalate of iron falls, which must be well washed and dried; when gently heated, the salt takes fire, leaving an impalpable powder of oxide of iron.

Putty Powder or Oxide of Tin.-Metallic tin is dissolved in nitro-muriatic acid, and precipitated from the filtered solution by liquid ammonia, both fluids being largely diluted with water. The peroxide of tin is then washed in abundance of water. Collect in a cloth filter, and squeeze as dry as possible in a piece of new linen. The mass is now subjected to pressure in a screw press, or between two lever boards, to make it as dry as possible. When the lump thus produced has been broken, it is placed in

a crucible, and closely covered up to | prevent jets from entering, and is then exposed and heated to a white heat, and ground for use in the usual way; this oxide is used specially for cements, and polishing astronomical object-glasses for astro-telescopes. The putty powder of commerce, if of good fair quality, is alloyed with about equal parts of tin and lead, which answers for ordinary purposes, but not for polishing lenses, in which good work is wholly dependent on the quality of the powder.

Razor Paste.-Mix fine emery intimately with fat and wax until the proper consistency is obtained in the paste, and then rub it well into the leather strap. Prepare the emery by pounding thoroughly in a mortar the coarse kind, throwing it into a large jug of water and stirring well. Immediately the large particles have sunk, pour off into a shallow plate or basin, and let the water evaporate. This emery is better for engraving and other purposes than that prepared at the emery mills. 2. The grit from a fine grindstone is very efficient for a razor paste. 3. Levigated oxide of tin, prepared putty powder, 1 oz.; powdered oxalic acid, oz.; powdered gum, 20 grains; make into a stiff paste with water, and evenly and thinly spread it over the strop. With very little friction, this paste gives a fine edge to the razor, and its efficiency is still further increased by moistening it. 4. Emery reduced to an impalpable powder, 2 parts; spermaceti ointment, 1 part; mix together, and rub it over the strop. 5. Jewellers' rouge, black-lead, and suet, equal parts; mix.

Cutting Pebbles.-The lapidary's bench is formed with a fly-wheel working horizontally, by hand-crank, with a leather strap passing over and communicating motion to a pulley and spindle, on which as wanted for use are successively fastened the following plates;-1st, the sliding plate of soft iron, very thin, turned up to run quite true on its spindle, the edge dressed with diamond powdered in a hardened steel mortar, and lubricated with oil of brick; turpentine or paraffin is also occasionally used.

The stone is held in the hand. The stone is to be reversed after some progress in the cut, to avoid dishing. The cut being completed, the grinding is performed by substituting the second plate of pewter, dressed with coarse emery and water; 3rd ditto, with fine emery and water; 4th, wooden plate, with sand and water; 5th, pewter plate, with rotten-stone and water; 6th, wood plate, covered with leather dressed with putty powder or tripoli, and slightly watered. There may be other plates or discs, but the object to be attained is having a succession of grindings, so that each succeeding plate shall remove the imperfections of polish left by its predecessor.

Polishing Vulcanite.. -1. Remove scratches with a smooth wet water of Ayr stone, and then polish in the lathe with fine pumice and a stiff brush. After washing the pumice off, polish it with whiting and soft brush. 2. The mathematical instrument makers treat it as brass-that is, for flat work they first use water of Ayr stone, and then rottenstone and oil. Turned work is polished in the lathe with rotten-stone and oil, taking care not to use too high a speed, which would heat the work. Some use lampblack and oil to finish with where a very high polish is wanted, or the bare palm of the hand, as in getting up silver plate. Chain and ornament makers use circular buffs for their flat work, made of sea-horse leather, and for work of irregular forms, buffs of calico. A number of pieces, 12 in. in diameter, are screwed together between flanges, like a circular-saw spindle, and used with rotten-stone, always taking care not to heat the work; brushes are not at all suitable for it.

Polishing Plaster Casts. 1. Put into 4 lbs. of clear water 1 oz. of pure curd soap, grated and dissolved in a well-glazed earthen vessel-then add 1 oz. of white beeswax, cut into thin slices; when the whole is incorporated it is fit for use. Having well dried the figure before the fire, suspend it by a twine, and dip it once in the varnish; upon taking it out, the moisture will appear to have been absorbed in 2 minutes'