Young's Demonstrative Translation of Scientific Secrets Part 28

533. TO CLEAN OLD BRa.s.s WORK FOR LACQUERING

First boil a strong lye of wood-ashes, which you may strengthen with soap-lees; put in your bra.s.s work, and the lacquer will immediately come off; then have ready a pickle of aquafortis and water, strong enough to take off the dirt; wash it immediately in clean water, dry it well, and lacquer it.

534. TO PREPARE FISH OIL FOR PAINT

Into a cask which will contain about 40 galls., put 32 galls. of good common vinegar; add to this 12 lbs. of litharge, and 12 lbs. of white copperas in powder: bung up the vessel, and shake and roll it well twice a-day for a week, when it will be fit to put into a ton of whale, cod, or seal oil, (but the southern whale oil is to be preferred, on account of its good colour and little or no smell:) shake and mix all together, when it may settle until the next day; then pour off the clear, which will be about seven-eighths of the whole. To clear this part, add 12 galls. of linseed oil, and 2 galls. of spirits of turpentine; shake them well together, and, after the whole has settled two or three days, it will be fit to grind white lead and all fine colours in; and, when ground, cannot be distinguished from those ground in linseed oil, unless by the superiority of colour. If the oil be wanted only for coa.r.s.e purposes, the linseed oil and oil of turpentine may be added at the same time that the prepared vinegar is put in; and, after being well shaken up, is fit for immediate use, without being suffered to settle. The residue or bottom, when settled by the addition of half its quant.i.ty of fresh lime-water, forms an excellent oil for mixing with all the coa.r.s.e paints for preserving outside work. All colours ground in the above oil, and used for inside work, must be thinned with linseed oil and oil of turpentine.

Gain by the above process.

One ton of fish oil, or 252 galls................ $151.20 32 galls. of vinegar, at 12-1/2 cts. per gall.... 4.00 12 lbs. litharge, at 7 cts. per lb............... 84 12 lbs. white copperas, at 8 cts. ditto.......... 96 12 galls. of linseed oil, at 90 cts. per gall.... 10.80 2 galls. of spirit of turpentine, at 40 cts..... 80 -------- $168.60

252 galls. of fish oil 12 ditto linseed oil 2 ditto spirit of turpentine 32 ditto vinegar --- 298 galls., at 90 cts. per gal. $268.20 Deduct the expense............. 168.60 -------- $ 99.60

535. PAINTING IN MILK

In consequence of the injury which has often resulted to sick and weakly persons from the smell of common paint, the following method of painting with milk has been adopted by some workmen, which, for the interior of buildings, besides being as free as distemper from any offensive odour, is said to be nearly equal to oil-painting in body and durability. Take 1/2 gall. of skimmed milk, 6 ozs. of lime newly slaked, 4 ozs. of poppy, linseed, or nut-oil, and 3 lbs. of Spanish white. Put the lime into an earthen vessel or clean bucket, and having poured on it a sufficient quant.i.ty of milk to make it about the thickness of cream, add the oil in small quant.i.ties at a time, stirring the mixture with a wooden spatula. Then put in the rest of the milk, and afterwards the Spanish white. It is, in general, indifferent which of the oils above-mentioned you use; but, for a pure white, oil of poppy is the best. The oil in this composition, being dissolved by the lime, wholly disappears; and, uniting with the whole of the other ingredients, forms a kind of calcareous soap. In putting in the Spanish white, you must be careful that it is finely powdered and strewed gently over the surface of the mixture. It then, by degrees, imbibes the liquid and sinks to the bottom. Milk skimmed in summer is often found to be curdled; but this is of no consequence in the present preparation, as its combining with the lime soon restores it to its fluid state.

But it must on no account be sour; because, in that case, it would, by uniting with the lime, form an earthy salt, which could not resist any degree of dampness in the air. Milk paint may likewise be used for out-door objects by adding to the ingredients before-mentioned 2 ozs. each more of oil and slaked lime, and 2 ozs.

of Burgundy pitch. The pitch should be put into the oil that is to be added to the milk and lime, and dissolved by a gentle heat. In cold weather, the milk and lime must be warmed, to prevent the pitch from cooling too suddenly, and to enable it to unite more readily with the milk and lime. Time only can prove how far this mode of painting is to be compared, for durability, with that in oil; for the shrinking to which coatings of paint are subject depends in great measure upon the nature and seasoning of the wood. The milk paint used for in-door work dries in about an hour; and the oil which is employed in preparing it entirely loses its smell in the soapy state to which it is reduced by its union with the lime.

One coating will be sufficient for places that are already covered with any colour, unless the latter penetrate through it and produce spots. One coat will likewise suffice, in general, for ceilings and stair-cases; two will be necessary for new wood. Milk painting may be coloured, like every other in distemper, by means of the different colouring substances employed in common painting. The quant.i.ty I have given in the receipt will be sufficient for one coat to a surface of about twenty-five square yards.

536. ETHEREAL SOLUTION OF GOLD

The following mode of effecting this solution (used chiefly for gilding steel) is recommended by Mr. H. Mill, in the "Technical Repository," as being superior to any previously made known. "The instructions," he says, "given in most elementary works on chemistry for this purpose are either erroneous or not sufficiently explicit."

The process answers equally well for either gold or platina.

Dissolve any quant.i.ty of gold or platina in nitro-muriatic acid, (aqua regia,) until no further effervescence is occasioned by the application of heat. Evaporate the solution of gold or platina, thus formed, to dryness, in a gentle heat, (it will then be freed from all excess of acid, which is essential,) and re-dissolve the dry ma.s.s in as little water as possible: next take an instrument which is used by chemists for dropping liquids, known by the name of a separating funnel, having a pear-shaped body, tapering to a fine sharp point, and a neck capable of being stopped with the finger or a cork, which may contain a liquid once or more; fill it with the liquid about one-quarter part, and the other three parts must be filled with the very best sulphuric ether. If this be rightly managed, the two liquids will not mix. Then place the tube in a horizontal position, and gently turn it round with the finger and thumb. The ether will very soon be impregnated with the gold or platina, which may be known by its changing its colour; replace it in a perpendicular position, and let it rest for twenty-four hours; having first stopped up the upper orifice with a cork. The liquid will then be divided into two parts--the darkest colouring being underneath. To separate them, take out the cork and let the dark liquid flow out: when it has disappeared, stop the tube immediately with the cork, and what remains in the tube is fit for use, and may be called gilding liquid. Let it be put into a bottle, and tightly corked. The muriate of gold or platina, formed by digesting these metals in nitro-muriatic acid, must be entirely free from all excess of acid; because it will otherwise act too forcibly on the steel, and cause the coating of gold to peel off. Pure gold must be employed; the ether must not be shaken with the muriate of gold, as is advised in chemical publications, for it will be sure, then, to contain acid; but if the two liquids be brought continually into contact by the motion described, the affinity between ether and gold is so strong as to overcome the obstacle of gravity, and it will hold the gold in solution. The ethereal solution may also be concentrated by gentle evaporation.

537. VARNISH POLISH

Take 2 ozs. of tripoli, reduced to fine powder; put it into an earthen pot or basin, with water to cover it; then take a piece of fine flannel, four times doubled, lay it over a piece of cork or rubber, and proceed to polish your varnish, always wetting it with the tripoli and water. You will know when the process is completed, by wiping a part of the work with a sponge and observing whether there is a fair and even gloss. Take a bit of mutton-suet and fine flour, and clean off the work. Or, the powdered tripoli may be mixed up with a little pure oil, and used upon a ball of serge, or of chamois leather, which is better. The polis.h.i.+ng may afterwards be completed with a bit of serge or cloth, without tripoli. Putty powder, and even common whiting and water, are sometimes used for polis.h.i.+ng; but they produce a very inferior effect to tripoli, except in the case of ivory, for which putty and water, used upon a rubber made of a hat, forms the best and quickest polish. Putty and water may likewise be used, in the same manner as just mentioned for ivory, in finis.h.i.+ng off the polish of pearl work, after it has first been polished very smooth with pumice-stone, finely powdered, and well washed to free it from impurities and dirt.

538. VARNISH FOR COLOURED DRAWINGS

Mix together 1 oz. of Canada balsam and 2 ozs. of spirits of turpentine. Before applying the composition, size the drawing or print with a solution of isingla.s.s in water; when this is dry, apply the varnish with a camel's-hair brush. The use of this varnish gives to coloured drawings and prints an appearance resembling that of oil paintings.

539. VARNISH FOR GLa.s.s

Reduce a quant.i.ty of gum tragacanth to powder, and let it dissolve for twenty-four hours in the white of eggs well beat up; then rub it gently on the gla.s.s with a brush.

540. TO CLEAN PICTURES

Having taken the picture out of its frame, take a clean towel, and making it quite wet, lay it on the face of your picture, sprinkling it from time to time with clear soft water; let it remain wet for two or three days; take the cloth off, and renew it with a fresh one; after wiping your picture with a clean wet sponge, repeat the process till you find all the dirt soaked out of your picture; then wash it well with a soft sponge, and let it get quite dry; rub it with some clear nut or linseed oil, and it will look as well as when freshly done.

541. ANOTHER METHOD

Put into two quarts of strong lye a quarter of a pound of Genoa soap rasped very fine, with about a pint of spirits of wine; let them simmer on the fire for half an hour, then strain them through a cloth; apply it with a brush to the picture, wipe it off with a sponge, and apply it a second time, which will effectually remove all dirt; then, with a little nut oil warmed, rub the picture, and let it dry; this will make it look as bright as when it came out of the artist's hands.

542. VARNISH FOR CLOCK FACES, &c.

Take of spirits of wine, 1 pint; divide it into four parts; mix one part with half an ounce of gum mastic, in a bottle by itself; one part of spirits and half an ounce of gum sandrac in another bottle; and one part of spirits and half an ounce of the whitest part of gum benjamin; mix and temper them to your mind; if too thick, add spirits; if too thin, some mastic; if too soft, some sandrac or benjamin. When you use it, warm the silvered plate before the fire, and with a flat camel-hair pencil stroke it over till no white streaks appear; which will preserve the silvering for many years.

543. VARNISH FOR BALLOONS

Take some linseed oil, rendered drying by boiling it with 2 ozs. of sugar of lead and 3 ozs. of litharge for every pint of oil till they are dissolved, which may be in half an hour. Then put 1 lb. of birdlime and half a pint of the drying oil into an iron or copper vessel, whose capacity should equal about a gallon, and let it boil very gently over a slow charcoal fire, till the birdlime ceases to crackle, which will be in about half or three-quarters of an hour; then pour upon it 2-1/2 pints more of the drying oil, and let it boil about an hour longer, stirring it frequently with an iron or wooden spatula. As the varnish, whilst boiling, and especially when nearly ready, swells very much, care should be taken to remove, in those cases, the pot from the fire, and to replace it when the varnish subsides; otherwise, it will boil over. Whilst the stuff is boiling, the operator should occasionally examine whether it has boiled enough , which may be known by observing whether, when rubbed between two knives, which are then to be separated from one another, the varnish forms threads between them, as it must then be removed from the fire. When nearly cool, add about an equal quant.i.ty of oil of turpentine. In using the varnish, the stuff must be stretched, and the varnish applied lukewarm. In 24 hours it will dry. As the elastic resin, known by the name of Indian rubber, has been much extolled for a varnish for balloons, the following method of making it, as practiced by M. Blanchard, may not prove unacceptable: dissolve elastic resin cut small in five times its weight of rectified essential oil of turpentine, by keeping them some days together. Then pour 1 oz. of this solution in 8 ozs. of drying linseed oil for a few minutes; strain the solution, and use it warm.

544. TO PREPARE RENNET TO TURN MILK

Take out the stomach of a calf as soon as killed, and scour it inside and out with salt; after it is cleared of the curd always found in it, let it drain a few hours, then sew it up with two good handsful of salt in it, or stretch it well salted on a stick, or keep it in the salt wet; and when wanted soak it a little in fresh water, and repeat the same when again required.

545. TO MAKE CHEESE

Put the milk into a large tub, warming a part till it is of a degree of heat quite equal to new; if too hot the cheese will be tough. Put in as much rennet as will turn it, and cover it over; let it stand till completely turned, then strike the curd down several times with the skimming-dish, and let it separate, still covering it. There are two modes of breaking the curd, and there will be a difference in the taste of the cheese according as either is observed: one is, to gather it with the hands very gently towards the side of the tub, letting the whey pa.s.s through the fingers till it is cleared, and ladling it off as it collects; the other is, to get the whey from it by early breaking the curd; the last method deprives it of many of its oily particles, and is therefore less proper. Put the vat on a ladder over the tub, and fill it with curd by the skimmer; press the curd close with your hand, and add more as it sinks, and it must be finally left two inches above the edge. Before the vat is filled, the cheese-cloth must be laid at the bottom, and when full, draw smoothly over on all sides. These are two modes of salting cheese; one by mixing it in the curd while in the tub, after the whey is out, and the other by putting it into the vat and crumbling the curd all to pieces with it, after the first squeezing with the hands has dried it. The first method appears best on some accounts, but not on all, and therefore the custom of the country must direct. Put a board under and over the vat, and place it in the press; in two hours turn it out and put a fresh cheese-cloth; press it again for eight or ten hours; then salt it all over, and turn it again in the vat, and let it stand in the press fourteen or sixteen hours, observing to put the cheese last made undermost. Before putting them the last time into the vat, pare the edges if they do not look smooth. The vat should have holes at the sides and at bottom, to let all the whey pa.s.s through; put on clean boards, and change and scald them.

546. TO PRESERVE CHEESE SOUND

Wash in a warm whey, when you have any, wipe it once a month, and keep it on a rack. If you want to ripen it, a damp cellar will bring it forward. When a whole cheese is cut, the larger quant.i.ty should be spread with b.u.t.ter inside, and the outside wiped to preserve it.

To keep those in daily use moist, let a clean cloth be wrung out from cold water, and wrapt round them when carried from the table.

547. TO MAKE CREAM CHEESE

Put 5 quarts of strippings, that is, the last of the milking, into a pan, with 2 spoonsful of rennet. When the curd is come, strike it down two or three times with the skimming-dish, just to break it; let it stand two hours, then spread a cheese-cloth on a sieve, put the curd on it, and let the whey drain; break the curd a little with your hand, and put it into a vat with a 2 lb weight upon it; let it stand twelve hours, take it out, and bind a fillet round; turn every day till dry, from one board to another, cover them with nettles or clean dock leaves, and put between two pewter-plates to ripen. If the weather be warm, it will be ready in three weeks.

548. ELEGANT AND INGENIOUS ARTS, &c.

Accomplishments.--These are very desirable for the household, because the inmates are made happier by refined and ingenious arts and pursuits, and are fitted to improve the taste of others.

Children and young persons, of both s.e.xes, should learn as many of these arts as they possibly can without neglecting duties. Pleasant modes of employing leisure hours save people from many temptations, and add much to the happiness of life.

549. GRECIAN PAINTING

Grecian painting is the art of imitating oil paintings. This truly beautiful imitation, if well done, is so perfect that none save connoisseurs can discern, at sight, the difference.

Engravings best suited to this style of painting are mezzotint or aquatint, though fine lithographs are used.