through the gold, as a guide. When dry, the unnecessary gold may be removed by rubbing with a small wad of damp cotton. The best water size is made by dissolving a piece of Russian isinglass about the size of a five cent piece in a pint of water. It should be boiled for about five minutes.

A very good backing material is made by thinning japan black with gold size japan, to which add about one-third spar varnish. A very effective letter is made by blending gold, lemon gold, and silver as follows: Gild one-third of letter deep gold, and when dry scratch or etch; blend with glass etching brush. Gild next section in lemon gold, etch as before, and finish with silver in the third section. Then back up in the usual manner.

We will next take up a few of the matt center effects. First gild and back up all the burnished gold outlines and ornaments on the job, and when dry, wash out all surplus gold and size in centers with clear gold size japan. When tack is reached, gild from the book as in board sign gilding. Another way of producing a plain matt center effect is to use lager beer, provided enough of it can be saved from its regular channel of usefulness, in the same manner as water size, and back up when dry, with the usual backing material. Another pretty center is made by sizing with gold size and then spattering with water from a stiff brush. When size is dry, gild with water size. The spatter will take a burnished gild. For the rough, or stippled gold centers, size with damar varnish, to which should be added one-tenth of its bulk of balsam fir, one-fifth of its bulk of quick-rubbing varnish, and a pinch of powdered pumice stone. Lay in the varnish and stipple with a short bristle brush. When hard, gild with water size and back up with varnish, colored with chrome yellow in japan.

For pearl centers, size with damar varnish and inlay pieces of mother of pearl as closely as possible. When the damar is dry, resize and cover with well-crumpled tin foil, which will serve to fill all crevices, and give the ornament a solid appearance.

One of the most interesting, and yet simplest jobs, especially to a workman who has pictorial ability, is etching gold on glass. This is a very effective way of reproducing emblems, trademarks, scrolls, etc. Mark

out carefully on thin tracing paper, fasten this to face of glass with gummed stickers, and gild entire drawing solidly, making an effort to do so with one gilding, that is without patching. When dry give a couple of hotwater baths to clear the gold, then remove paper drawing to gilded side of glass, face to gold, with a piece of carbon paper between. The thinness of the drawing paper will enable you to transfer the drawing directly to the gold with the aid of the carbon paper. Then coat the outside or face of the glass with lampblack in distemper. This black will enable you to note each scratch or mark made upon the gold. A stick of jeweler's peg wood and a short bristle tapestry brush are the proper tools. However, a glass etching brush, the bristles of which are made of glass will be found the most effective for the work. Proceed by etching in the shadows, leaving the gold for the highlights. When complete, back the entire etching with backing-up black, and remove the surplus gold. All gold work on glass should be protected on the back by a coat of lead and varnish and finally by a coat of best spar varnish, which should be allowed to extend onto the clear glass a trifle.

In conclusion I will enumerate a few tips and don'ts picked up at random:

Don't try to do nice gold work on glass that is not clean; it is a waste of time.

A chamois skin is the best for cleaning and polishing glass.

To make ordinary school chalk mark perfectly on glass wash the glass with stale beer.

Should you accidentally apply a piece of gold to the glass too soon after sizing with the water size, and should it start to slide down, rub your finger quickly on the side of your nose, then under the sliding leaf, and watch it slide up hill.

Don't do gold leaf work on the inside of windows of stores where condensation of moisture and freezing are apt to occur. It will not stick.

Don't paint large, solid backgrounds on the plate glass windows. It interferes with the expansion and contraction of the glass glass and may cause it to break.

Don't be a cheap sign writer. It isn't necessary.

Don't expect a dub painter to write any thing worth listening to.

REMARKABLE

WOOD PRESERVATION.

There is at La Brae, near Los Angeles, Cal., a spot of extraordinary scientific value. It is an asphalt deposit from which bones of prehistoric animals have been taken by the ton, among them the skeleton of a man supposed to be 200,000 years old. The asphalt pit (writes S. F. Maxwell in the Scientific American) was apparently once a fissure filled with viscid oil or magna. Animals that ventured upon it sank and perished. The place is full of bones, skeletons of camels, sloths, tigers, wolves, bisons. It is believed that most of these animals belonged to the Pleistocene period, immediately preceding the modern, and that they lived some 200,000 years ago.

A log of wood with bark still on it was found standing upright among the bones. How it happened to reach that place and attain that posture is a matter for speculation. The bark is rough and stringy, but falls to shreds when the asphalt is dissolved out with gasoline. The wood is quite dark. The color does not seem to be due to the asphalt, because when a gramme of chips is soaked in a few cubic centimetres of gasoline for a day or so, little color is imparted to the liquid. Neither does the wood respond to tests for tannin. Although brittle and hard to cut in thin cross-sections, the wood does not differ materially in hardness from other soft woods.

The tree was of very slow growth. Each annual ring is about three-tenths of a millimetre broad, and there are from eleven to fifteen rows of wood cells to the ring. The resin ducts may be plainly seen with globules of resin in them. The state of the wood's preservation is wonderful. The delicate cells, even down to their bordered pits and tori, are all in place and unbroken, though apparently slightly compressed. Under the microscope the wood looks as fresh as a sample newly cut from a living tree, except that the grains of starch or other substance in the medullary rays are slightly shriveled, and threads of fungus are visible. The wood appears to be one of the junipers.

The tree was evidently dead before it went into the asphalt. The presence of the fungus is the proof of this. There are many fine threads, or mycelia, not more than twelve ten-thousandths of a millimetre in diameter, ramifying through the wood, lengthwise with the wood cells and also penetrating their lateral walls. Some of these threads are a centimetre long. The position of the fungus indicates that its activities were suddenly ended. That doubtless occurred when air was excluded by the log's immersion in the plastic asphalt. Everything remains as it was at the last minute.

Many of the mycelium tips appear just in the act of piercing a cell wall. Here and there are branches just budding from a main thread. It reminds one of the fate of Pompeii-the suddenness with which life was blotted out. Substitute a colony of fungus in a log of wood for a city full of men; a pool of oil for hot ashes; and the similitude is complete.

Oil is evidently an excellent preservative. During two thousand centuries that tree lay buried in asphalt, and it comes out as well preserved as it was the day it went in. The wood's examination was made with a power of 300 diameters on an ordinary microscope. The wood sections were cut from points within two centimetres of the bark.

HOW VARNISH DRIES.

Often in these columns we have said that a warm temperature and proper ventilation were essential to the proper drying of varnish. However, we have never given the reason, which is this: Varnish is composed of three essential ingredients: gum, oil and an evaporable material, such as turpentine, or other volatile thinners, the only purpose of which is to render the gum and oil sufficiently fluid so that it can be applied. The gum and oil however, do not evaporate, for obviously if they did there would be nothing left on the surface. They become hard by a chemical and physical change, caused by the absorption of oxygen from the air.

Obviously, a fairly warm temperature is necessary to the proper drying of varnish, to quickly evaporate the volatile thinners. And proper ventilation is essential, for this causes circulation of air, which brings with it oxygen, which is absorbed by the coating of gum and oil, causing the solidification of. the coating.

Of course, with some inferior varnishes containing adulterated oils and of improper manufacture, you will have trouble with varnish properly hardening no matter what you do to insure perfect results. But given good hard drying varnishes and an even temperature of about 70 degrees and proper ventilation, you will get perfect results every time. "Varnish Talks," Pratt and Lambert.

DEADLY WOOD ALCOHOL.

In Russia, 80 cases of wood alcohol poisoning followed by blindness, have been reported. The poison acts quickly

that, as a rule, treatment is too late. In the milder cases a restitution or partial restitution of the lost power of vision takes place; in the severer cases vision becomes totally lost, or it improves for a while, but ultimately is entirely lost.

NE of the most interesting collections in this country is the collection of old leathers acquired recently by George K. Birge, of Buffalo. It is part of an assemblage owned at one time by M. J. Teunissen, of The Hague, whose father before him had been untiring in his quest for these rare specimens. Both father and son were antiquarians and as an entirety it was undoubtedly one of the finest single collections in the world, so important indeed, that the imperial government of Japan negotiated for its purchase for the National Museum at Tokyo, but the outbreak of the recent war between Japan and Russia checked negotiations.

The art of decorating leathers goes back to the earliest ages. The Greeks, who inherited the arts of Persia and Babylonia, covered their couches with skins and their leathers

were unquestionably decorated. Decorated leathers became famous in the Ninth and Tenth Centuries as Spanish leathers or Cordova leathers and may be traced to the Saracenic invasion of Spain.

The Arabian Caliphate developed the best of the Eastern arts. When the Arabi

ans undertook their European invasion they were joined in Northern Africa by the Berbers or Moors and in 711 lower Spain was conquered. In 755 the Caliphate of Cordova was established and in the Ninth and Tenth Centuries this reached the most brilliant period of Moorish civilization and Cordova was the seat of science and the arts.

Here we have undoubtedly the introduction of the illuminated leathers in Spain. For many years the term guadamecil was applied to these leathers, and it is a significant fact that the word comes from the name of the village Ghadames, a town in Barbary, where the leather craft was practised. This conclusion, however, is not final. Some Spanish authorities maintain that the art originated in Andalusia.

Another authority, Laborde, volume V., page 231, says:

"Spain lays claim to the invention of the art of gilding leather; it is asserted that, after being discovered there, the secret was carried to Naples by Peter Paul Majorano."

However this may be, the preparation of these leathers grew to be a most important industry in Cordova, Seville, Granada, Toledo, Barcelona and later throughout Italy and Flanders, where they were introduced in the Eleventh Century, but even these Flemish leathers and French leathers were called Cordovas. The French called them cuir de Cordova. The Dutch called them goud leder

or gold leather. The Germans called them Leder Tapeten or leather hangings, the Spanish, cueros de Cordova.

None of these primitive leathers now exists, and consequently details of their workmanship have perished with them. The earliest examples were an imitation of wool brocades. The artist employed beaten silver together with the colors, red, green, blue, black, white and carmine, applied in oils or sometimes, although the law prohibited this, in tempera. The leatherworkers tanned the hides themselves, stamping the pattern from a wooden mould, and then engraving on them. The hides were those of rams. Gold was introduced between 1529 and 1543. The beaten gold was laid upon the oiled leather and crushed in with a heated iron. The irons had to be heated only moderately, because if overheated, they would turn the hide. The importance of this industry in Spain may be judged by the fact that in many cities whole sections were devoted to the making of decorative leather.

The industry enriched Cordova and as late as the Sixteenth Century, leather decorating was an important industry. They served a use upon the walls and floors of palaces and castles, as table covers, counterpanes, bed hangings, for cushions, curtains, furniture, covering seat backs and even for floor coverings. The growing popularity of wall-pictures, together with the importation of French fashions at the death of Charles the Second, crippled and ultimately killed the decorative leather industry of Spain which may be said to have ended with 1685.

GENERAL FUNCTIONS OF PAINT
MATERIALS.

Paint is composed of pigments, drying oils, such as linseed oil, dryers or japans and volatile oils or thinners, such as turpentine; and sometimes varnish for the purpose of adding durability and lustre.

Pigments give the paint necessary opacity and coloring properties and contribute to the durability of the coating; the properties and durability of different pigments varying considerably, so that different pigments are used to produce as nearly as possible a perfect combination.

The drying oils absorb oxygen from the air, which causes a chemical action that solidifies them into a hard, adherent film which in combination with the pigments imparts the protective, preservative powers to paint. They also give the paint fluidity, insure an even distribution of the pigment over the surface and produce in the paint the desired lustre.

Volatile oils are used chiefly for their mechanical effect as they evaporate soon after the paint is applied and practically form no part of the eventual paint film. They render the more or less sticky, pastelike mass of oil and pigment of proper consistency for quick, easy and proper application, enable the painter to reduce the gloss of undercoats, and thus improve the adhesion of subsequent coats.

From the above it is apparent why the priming coat should always be thinned more than the subsequent coats-why the undercoats should be thinned more than the finishing coat, and why minimum thinning of the finishing coat will produce the fullest, richest gloss. It is also apparent that excessive thinning will impair durability, inasmuch as the thinner has permanent place in the paint film.

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Dryers are certain metallic oxides and salts which cause the drying oil to absorb oxygen. They are usually prepared for use by combining with oil or gums by means of heat and reducing with volatile oils. Boiled oil is oil in which a small amount of the metallic dryers have been incorporated by heat:

Japan or japan dryer is much similar to other dryers with the exception that it contains gum and has more body.

The characteristic of the drying oils is to harden from the surface inward. This, of course, makes it impossible to tell when the film is thoroughly dry, with the result that a new coat might be applied before the preceding one was dry, causing serious trouble. Ordinary dryers do not overcome this difficulty.

Varnishes are sometimes used in paint, particularly for interior paint, along with

drying oils. They yield a firmer, smoother, more lustrous coating, capable of being rubbed. When varnish is used entirely instead of drying oil, the resultant mixture is known as enamel.-Pratt and Lambert's "Varnish Talks."

PAINTING ON METALS.

The painting of various kinds of metal surfaces is dealt with by Mr. A. Ashmun Kelly in the "National Builder." Among the hints given the following are of wide application:

Repainting Iron and Steel Work.

Select dry weather for this work, as freezing or wet weather is very bad. Free the surface from all scale and dirt, rust, etc., a wire brush being a very useful tool for the purpose. If any rust, etc., is allowed to remain under the new coat of paint you may be sure that it will show up later on. If the work is in fairly good condition the bad places may be scraped and touched up with paint, matching the old paint as well as possible, and when dry, giving the whole surface a coat of paint, or in some cases just a coating of raw or boiled oil will do, as in many cases the oil is the only thing that has left the paint. This plan works equally well in many cases of woodwork, on houses, etc. Often a coat or even two coats of paint are applied when all that is really necessary is a coat of oil with a possible preliminary touching up with paint. When painting over old painted metal work a paint containing some turpentine is well, as this fluid penetrates well, getting the paint down into any possible pores of the metal, for, of course, it is necessary that the new paint adhere well with the old.

Painting Galvanized Iron.

It must now be pretty well understood that galvanized iron should not be painted until it has stood to the weather for a year or so, or before it has been treated with a liquid to cut the so-called grease or galvanizing. In many instances new galvanized work looks well enough without paint, and in such cases it is a waste of time and money to apply paint to it. But where the finish demands the painting of the galvanized work it may be prepared with this formula: Take 2 oz. each of copper chloride, copper nitrate, and sal ammoniac, all to be dissolved in one gallon of soft water, preferably. Then add 2 oz. of muriatic acid. Mix in a wooden vessel, and apply with a broad bristle brush one coat. When dry it may be painted. No paint or varnish will scale from this surface. A gallon of this wash will coat about twentyfive or thirty squares of 100 ft. each. It is inexpensive and easily made and applied. At first it is black, but this turns

Copper well the gal

acetate will do the work just as as the other mixture, 6 oz. to lon of water. A film of black copper oxide is deposited on the surface, and to this a paint will readily adhere. Copper acetate is simply an acid in which copper has been soaked. The government specifies for the purpose simply strong vinegar, while some master painters advise and use strong ammonia water, allowing it to dry on, not removing it but painting over it. Some railroads cleanse the surface with benzine, then apply a coat of varnish, this seeming to give good results. They use coach finishing varnish for this purpose. Then any approved paint may be applied, though some of the foremen painters add some varnish to the paint, which would seem to be a good plan. Add one pint of varnish to gallon of paint.

Painting Galvanized Roofing.

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After the roof has stood to the weather for a year it may safely be painted. It has been found by careful observation that the best adhering and wearing paints for such roofing are red lead, burnt umber, burnt sienna, Indian red, Prussian blue, lampblack, and graphite, the poorest adhering paints being white zinc, lithopone, clay, etc. For first coat red lead is always good. for the appearance, where a room may be visible, white makes a cool roof, but few would care for it. Green and red are pleasing colors. Mixtures of the desirable pigments may be employed to produce pleasing colors. Red lead tones with lamp-black do well. White reflects heat, keeping the roof cool, while dark colors absorb heat, making a warm roof, and injuring the paint, too. Ssually one coat of paint is sufficient on any metal roof, and too much paint results in peeling, etc.

The effects of over-exertion are receiving more attention in America, though Europe has always been a leader. We have definitely shown that certain fatal conditions invariably follow prolonged hard muscular labor. At present there is more said upon the damage to the nervous system from prolonged strain. It is found that nervous breakdown is the cause of over half of the invalidism of workmen and one-third that of working women. It is generally conceded that this result is due to nerve strains of the unnatural conditions of modern industrialism which require an unwholesome effort of the attention.

We should have predicted this, for we have long known the laws of fatigue. Accidents and clerical errors are due to mental fatigue, as a rule, and gradually increase in number up to noon, but drop after the noon rest, when they mount up