PAINTS

(See also Acid-Proofing, Ceramics, Enamels, Fireproofing, Glazing, Painting Processes, Pigments, Rust Preventives, Varnishes, and Waterproofing.)

Paint Bases:

Dry Bases For Paints.

Buff.—
Yellow ocher	44 pounds
Whiting	6 pounds
Oxide of zinc	5 pounds
Plaster of Paris	․¹/₂ pound
Brick Brown.—
Yellow ocher	26 pounds
Calcined copperas	4 pounds
Red hematite	1 ¹/₄ pounds
Best silica	7 pounds
Whiting	18 pounds
Gray.—
Oxide of zinc	30 pounds
White lead	6 pounds
Whiting	12 pounds
Bone black	¹/₄ pound
Yellow ocher	2 pounds
Crimson.—
Indian red	25 pounds
Crocus martis	7 pounds
Oxide of zinc	6 pounds
Whiting	6 pounds
Vandyke Brown.—
Yellow ocher	25 pounds
Whiting	18 pounds
Umber	4 pounds
Oxide of zinc	7 pounds
Purple oxide of iron	1 pound
Blood Red.—
Crocus martis	30 pounds
Whiting	20 pounds
Hematite	3 pounds
Silica	6 pounds
Venetian red	2 pounds
Drab.—
Yellow ocher	40 pounds
Whiting	10 pounds
Oxide of zinc	8 ¹/₂ pounds
Sulphate of barytes	1 pound

Paint For Blackboards.—

Shellac	1 pound
Alcohol	1 gallon
Lampblack (fine quality)	4 ounces
Powdered emery	4 ounces
Ultramarine blue	4 ounces

Dissolve the shellac in the alcohol. Place the lampblack, emery, and ultramarine blue on a cheese-cloth strainer, pour on part of the shellac solution, stirring constantly and gradually adding the solution until all of the powders have passed through the strainer.

Dark-green Paint For Blackboards.

Bronzing Solutions For Paints.

I.—The so-called “banana solution” (the name being derived from its odor) which is used in applying bronzes of various kinds, is usually a mixture of equal parts of amyl acetate, acetone, and benzine, with just enough pyroxyline dissolved therein to give it body. Powdered bronze is put into a bottle containing this mixture and the paint so formed applied with a brush. The thin covering of pyroxyline that is left after the evaporation of the liquid protects the bronze from the air and keeps it from being wiped off by the cleanly housemaid. Tarnished picture frames and tarnished chandeliers to which a gold bronze has been applied from such a solution will look fresh and new for a long time. Copper bronze as well as gold bronze and the various colored bronze powders can be used in the “banana solution” for making very pretty advertising signs for use in the drug store. Lettering and bordering work upon the signs can be done with it. Several very small, stiff painters’ brushes are needed for such work and they must {490} be either kept in the solution when not in use, or, better still, washed in benzine or acetone immediately after use and put away for future service. As the “banana solution” is volatile, it must be kept well corked.

II.—A good bronzing solution for paint tins, applied by dipping, is made by dissolving Syrian asphaltum in spirits of turpentine, etc., and thinning it down with these solvents to the proper bronze color and consistency. A little good boiled oil will increase the adherence.

Paint Brushes.

Paint brushes which have dried up as hard as stone can be cleaned in the following manner: Dissolve 1 part soda in 3 parts water; pour the solution in a cylinder glass, and suspend in it the brushes to be cleaned, so that they are about 2 inches from the bottom of the vessel. Let it remain undisturbed at a temperature of 140° to 158° F., 12 to 24 hours, after which the most indurated brushes will have become soft, so that they can be readily cleaned with soap. It is essential, however, to observe the temperature, as bristle brushes will be injured and spoiled if the heat is greater.

Black.—a Permanent Black Of Rich Luster For Metal Boxes.

Dead White On Silver Work, Etc.

White Coating For Signs, Etc.

To Prevent Crawling Of Paints.

In some instances, however, crawling may be traced to a defective varnish. The latter, after drying evenly on a well-prepared paint surface will at times crawl, leaving small pitmarks. For this, the simple remedy consists in purchasing varnish from a reputable manufacturer.

Fireproof Paints:

Fireproof And Waterproof Paints.

Preparation of the Bases.—The cellulose (of wood, paper, cotton, linen, ramie, or hemp) is put in contact with two-thirds part of sulphuric acid of 66° Bé. and one-third part of nitric acid of 42° Bé. for some 20 or 30 minutes, washed with plenty of water, and kept for 24 hours in a tank of water supplied with an energetic current.

The nitro-cellulose thus obtained is bleached for this purpose; a double hypochlorite of aluminum and magnesium is employed. This is obtained by grinding together 100 parts of chloride of lime, 60 parts of aluminum sulphate, 23 parts of magnesium sulphate, with 200 parts of water.

When the nitro-cellulose is bleached and rewashed, it is reduced to powder and dried as thoroughly as possible. It is then placed in a vat hermetically closed and put in contact with the indicated proportion of calcium chloride dissolved in alcohol. This solution of calcium chloride should be prepared at least 24 hours in advance and filtered.

Composition of the Coating.—This has the following constituents: Bases (nitro-cellulose and solution of calcium chloride), 1 part; amyl acetate (solvent of the bases), 5 parts, by weight; sulphuric ether of 65°, 1.650 parts, by weight; alcohol, 0.850 parts, by weight; one of these powders, alum, talc, asbestos, or mica, 0.100 parts. Other solvents may be employed instead of amyl acetate; for example, acetone, acetic acid, ether alcohol, or methylic alcohol. The ether alcohol furnishes a product drying very quickly. If a very pliant coating is desired, the amyl acetate is employed preferably, with addition of vaseline oil, 0.20 parts, and lavender oil, 0.010 parts.

Method of Operating.—The sulphuric acid is mixed with the alcohol, and left for an hour in contact, shaking from time to time. Afterwards the amyl acetate is added, and left in contact for another hour under similar agitation. In case of the employment of vaseline oil and lavender oil, these two are mingled in ether alcohol. The base is introduced and left in contact for 24 hours, with frequent agitation. The fluidity of the product is augmented by increasing the quantity of the solvent.

Properties.—Wood covered with this coating is fireproof, non-hygrometric, and refractory to the electric current. It also resists the action of acids and alkalies. Metals covered with it are sheltered from oxidation, and effectually insulated on their surface from the electric current. The coating is liquid in form, and applied like collodions, either by the brush or by immersion or other suitable method.

Paint Deadening.

Another way is to add white wax instead of water to the last coating. This wax paint also gives a handsome dullness but is more difficult of treatment. A nice matt coating is also obtained by addition of Venetian soap, dissolved in water instead of the wax. This is very desirable for church decorations where exceptionally large surfaces are to be deadened.

Paint Dryers:

I.—	Ordinary barytes	25 pounds
	Whiting	4 pounds
	Litharge	2 pounds
	Sulphate of zinc	2 pounds
	Sugar of lead	2 pounds
	Boiled linseed oil	5 pounds
	Plaster of Paris	¹/₂ pound
II.—	Whiting	16 pounds
	Barytes	16 pounds
	White lead	3 pounds
	Boiled linseed oil	³/₄ gallon

Paints For Gold And Gilding:

Gold Paints.

For making gold paint like the so-called “washable gold enamel” that is sold by the manufacturers at the present time, it is necessary to mix a celluloid varnish with the French flake bronze powder. This varnish is made by dissolving transparent celluloid in amyl acetate in the proportion of about 5 per cent of celluloid.

Transparent celluloid, finely shredded	1 ounce
Acetone, sufficient quantity.
Amyl acetate to make 20 ounces.

Digest the celluloid in the acetone until dissolved and add the amyl acetate. From 1 to 4 ounces of flake bronze is to be mixed with this quantity of varnish. For silver paint or “aluminum enamel,” flake aluminum bronze powder should be used in place of the gold. The celluloid varnish incloses the bronze particles in an impervious coating, air-tight and water-tight. As it contains nothing that will act upon the bronze, the latter retains its luster for a long period, until the varnished surface becomes worn or abraded and the bronze thus exposed to atmospheric action.

All of the “gold” or, more properly, gilt furniture that is sold so cheaply by the furniture and department stores is gilded with a paint of this kind, and for that reason such furniture can be offered at a moderate price. The finish is surprisingly durable, and in color and luster is a very close imitation of real gold-leaf work. This paint is also used on picture frames of cheap and medium grades, taking the place of gold leaf or the lacquered silver leaf formerly used on articles of the better grades; it is also substituted for “Dutch metal,” or imitation gold leaf, on the cheapest class of work.

A cheaper gold paint is made by using an inexpensive varnish composed of gutta percha, gum dammar, or some other varnish gum, dissolved in benzole, or in a mixture of benzole and benzine. The paints made with a celluloid-amyl-acetate varnish give off a strong banana-like odor when applied, and may be readily recognized by this characteristic.

The impalpably powdered bronzes are called “lining” bronzes. They are chiefly used for striping or lining by carriage painters; in bronzing gas fixtures and metal work; in fresco and other interior decoration, and in printing; the use of a very fine powder in inks or paints admits of the drawing or printing of very delicate lines.

Lining bronze is also used on picture frames or other plastic ornamental work. Mixed with a thin weak glue sizing it is applied over “burnishing clay,” and when dry is polished with agate burnishers. The object thus treated, after receiving a finishing coat of a thin transparent varnish, imitates very closely in appearance a piece of finely cast antique bronze. To add still more to this effect the burnishing clay is colored the greenish black that is seen in the deep parts of real antique bronzes, and the bronze powder, mixed with size, is applied only to the most prominent parts or “high lights” of the ornament. {493}

Since the discovery of the celluloid-amyl-acetate varnish, or bronze liquid, and its preservative properties on bronze powders, manufacturers have discontinued the use of liquids containing oils, turpentine, or gums, since their constituents corrode the bronze metal, causing the paint finally to turn black.

Gilding In Size.

The raw stuff of the red size is bolus, which is dug in France and Armenia in excellent quality. Besides the red size there are yellow, white (pipe clay), blue, and gray (alumina), which are used for certain purposes, to enumerate which here would lead too far.

For burnish gold, always take yellow size for ground work. Dip a finely ground bristle brush in the gold size prepared for use; fill a well-cleaned glass (holding 1 pint) half full of water, and add the size contained in the brush, also about 4 to 5 spoonfuls of pure alcohol. It is advisable not to take too much size; the liquid, when applied, must hardly have a yellow tint. When this is dry soon after, commence applying the size, for which a hair pencil is used. The essentials are to paint evenly and not too thickly, so that the tone remains uniform. Apply three coats of size.

When the size is laid on correctly and has become dry, brush the whole with a special brush, or rub with a flannel rag, so as to obtain the highest possible luster. The size must not stand too long; otherwise no gloss can be developed. After brushing, coat the work with weak glue water and wrap it up in tissue paper if the gilding is not to be done at once.

The strictest cleanliness is essential, as the red gold size is very sensitive. The parts where the size has been applied must not be touched with the hand, else grease spots will ensue, which will make a flawless gloss in gilding impossible. The least relaxation of the necessary attention may spoil the whole job, so that everything has to be ground off again.

The necessary tools for the application of gold leaf are: Hair pencils of various sizes, tip, cushion, and gilding knife, as with oil-gilding. Take pure alcohol or grain brandy, and dilute with two-thirds water. When ready to apply the gold leaf, dip a hair pencil of suitable size into the fluid, but do not have it full enough that the alcohol will run on the size ground. Moisten a portion of the ground surface as large as the gold leaf, which is laid on immediately after. Proceed in the same manner, first moistening, then applying the ready-cut gold leaf. The latter must not be pressed on, but merely laid down lightly, one leaf a little over the edge of the previous one, without using up too much gold. Technical practice in gold-leaf gilding is presupposed; through this alone can any skill be acquired, reading being of no avail.

The leaf of gold being applied, all dust must be swept off by means of a light, fine hair pencil (but never against the overlapping edges), and the burnishing is commenced. For this purpose there are special agate tools of the shape of a horn. Flint stone, blood stone, and wolf’s teeth are sometimes, but gradually more seldom, employed. Burnish till a full, fine luster appears; but very carefully avoid dents and lines, not to speak of scratches, which would be very hard to mend.

Gold Enamel Paints.—

I.—	Pure turps	6 pints
	Copal varnish	1 pint
	Good gold bronze	6 ¹/₂ pounds
	Calcis hydrate (dry-slaked lime)	¹/₂ ounce

Mix the varnish and turps at a gentle heat, then slake well with the lime, and settle for a few days, then pour off the clean portion and mix with the powder.

II.—	White hard varnish	1 gallon
	Methylated spirit	³/₄ gallon
	Gold bronze	12 pounds
	Finely powdered mica	3 ounces

Mix the varnish and the spirit, reduce the mica to an impalpable powder, mix with the gold, then add to the liquid. Many bronze powders contain a goodly {494} proportion of mica, as it imparts brilliancy. Powdered mother-of-pearl is used also.

Graining With Paint:

Oak Graining.

Birch.

Maple.

Ash.

Medium Oak.

Light Oak.

Dark Oak.

Satin Wood.

Pollard Oak.

Pitch Pine.

Knotted Oak.

Italian Walnut.

Rosewood.

Dark Mahogany.

Light Mahogany.

American Walnut.

Luminous Paints.

The illuminating power of the phosphorescent masses obtained by heating strontium thiosulphate or barium thiosulphate is considerably increased by the addition, before heating, of small quantities of the nitrates of uranium, bismuth, or thorium. Added to calcium thiosulphate, these nitrates do not heighten the luminosity or phosphorescence. The product from strontium thiosulphate is more luminous than that of the barium compound. Among the best luminous paints are the following:

I.—Lennord’s.—One hundred parts, by weight, of strontium carbonate; 100 parts, by weight, of sulphur; 0.5 parts, by weight, of potassium chloride; 0.5 parts, by weight, of sodium chloride; 0.4 parts, by weight, of manganese chloride. The materials are heated for three-quarters of an hour to one hour, to about 2,372° F. The product gives a violet light.

II.—Mourel’s.—One hundred parts, by weight, of strontium carbonate; 30 parts, by weight, of sulphur; 2 parts, by weight, of sodium carbonate; 0.5 parts, by weight, of sodium chloride; 0.2 parts, by weight, of manganese sulphate. The method of treatment is the same as in the first, the phosphorescence deep yellow. {495}

III.—Vanino’s.—Sixty parts, by weight, of strontium thiosulphate; 12 parts, by weight, of a 0.5 per cent acidified alcoholic solution of bismuth nitrate; 6 parts, by weight, of a 0.5 per cent alcoholic solution of uranium nitrate. The materials are mixed, dried, brought gradually to a temperature of 2,372° F., and heated for about an hour. The phosphorescence is emerald green.

IV.—Balmain’s.—Twenty parts, by weight, of calcium oxide (burnt lime), free from iron; 6 parts, by weight, of sulphur; 2 parts, by weight, of starch; 1 part, by weight, of a 0.5 per cent solution of bismuth nitrate; 0.15 parts, by weight, of potassium chloride; 0.15 parts, by weight, of sodium chloride. The materials are mixed, dried, and heated to 1,300° C. (2,372° F.). The product gives a violet light.

To make these phosphorescent substances effective, they are exposed for a time to direct sunlight; or a mercury lamp may be used. Powerful incandescent gas light also does well, but requires more time.

Paints For Metal Surfaces:

Blackening Ornaments Of Iron.

II.—This process protects the iron from rust for a long time. The treatment consists in coating the objects very uniformly with a thin layer of linseed-oil varnish, and burning it off over a charcoal fire. During the deflagration the draught must be stopped. The varnish will first go up in smoke with a strong formation of soot, and finally burn up entirely. The process is repeated, i. e., after one coating is burned off a new one is applied, until the parts exhibit a uniformly handsome, deep-black color. Next, wipe off the covering with a dry rag and heat again, but only moderately. Finally, the articles are taken from the fire and rubbed with a rag well saturated with linseed-oil varnish. The black turns completely dull, and forms a real durable covering for the objects.

Black For Polished Iron Pieces.

Glossy Black For Bicycles, Etc.—

Amber	8 ounces
Linseed oil	4 ounces
Asphaltum	1 ¹/₂ ounces
Rosin	1 ¹/₂ ounces
Oil turpentine	8 ounces

Heat the linseed oil to boiling point, add the amber, asphaltum, and rosin, and when all melted remove from the fire and gradually add the turpentine.

Japan Black.

Brass And Bronze Protective Paint.

Paint For Copper.

Priming Iron.

It is advisable that articles made of iron should first be coated with linseed-oil varnish. It dries slowly, hardens, and enables the operator afterwards to exercise an effective control over the condition of his material. Iron must be absolutely dry and free from rust when it is to be painted. It is best to apply next a coating of hot linseed oil; when dry this should be followed by a priming of pure red lead in good linseed oil, and the iron should then be painted as desired, using ground oil paints and leaving an interval of a week between each coating. Cementing should be done after the red lead priming, but the last coat must not be given until the whole is thoroughly dry. Bright oil paints and an upper coating with plenty of oil resist the effects of heat better than thin coatings; moreover, rust can be detected in its early stages with the former. Coatings of tar and asphalt (asphalt dissolved in turpentine) are practicable for underground pipes, but are not adapted for pipes exposed to the air, as they are quickly spoiled. Asphalt varnish, used for coating coal scuttles, fire screens, etc., consists of asphalt dissolved in linseed-oil varnish. Iron stoves and stovepipes are best coated with graphite.

Galvanized Iron.

Another method which has been tested and found effective is to make a solution as follows: One ounce of chloride of copper; 1 ounce nitrate of copper; 1 ounce sal ammoniac, dissolved in 2 quarts of soft water, to which is added 1 ounce of crude or commercial hydrochloric acid. This solution should be made in an earthenware dish or pot, or in glass or stoneware, as tin will precipitate the copper salts and make the solution imperfect. To large surfaces this solution is applied with a broad brush, when the surface assumes a deep black color, which in drying out in from 12 to 24 hours becomes a gray white, upon which the properly prepared primer will take a permanent grip. On the film so produced a much thinner paint will cover very much better than a stouter paint would on the untreated galvanized or ordinary iron surface. A single trial will convince the craftsman that this treatment is a method that will give lasting results, provided he tries the same priming paint on the treated and untreated surface.

To Paint Wrought Iron With Graphite.

Paint For Iron Bodies Exposed To Heat.

White.—White lead or sulphate of barium.

Yellow.—Chromate of barium, ocher, or uranium yellow.

Green.—Chromic oxide or ultramarine green.

Blue.—Ultramarine.

Brown.—Oxide of cadmium, oxide of manganese or terra di sienna.

Red.—English red or chrome red.

Bronze powder in a suitable quantity may be added to the mixture, but not more paint should be prepared than can be used up in a few hours. The bronze powder may also be strewn on the fresh paint, or applied with a dry brush, to enhance the gloss. This paint is not affected by heat, and is inodorous.

Protective Coating For Bright Iron Articles.

Rust Paints.

II.—A material known under the names of lardite, steatite, agalmatolite, pagodite, is excellently adapted as a substitute for the ordinary metallic protective agent of the pigments and has the property of protecting iron from rust in an effective manner. In China, lardite is used for protecting edifices of sandstone, which crumbles under the action of the atmosphere. Likewise a thin layer of powdered steatite, applied in the form of paint, has been found valuable there as a protector against the decay of obelisks, statues, etc. Lardite, besides, possesses the quality of being exceedingly fine-grained, which renders this material valuable for use in ship painting. Ground steatite is one of the finest materials which can be produced, and no other so quickly and firmly adheres to the fibers of iron and steel. Furthermore, steatite is lighter than metallic covering agents, and covers, mixed in paint, a larger surface than zinc white, red lead, or iron oxide. Steatite as it occurs in Switzerland is used there and in the Tyrol for stoves, since it is fireproof.

Steel.

Paints For Roofs And Roof Paper:

Carbolineum.

I.—Pale.—Melt together in an iron kettle, over a naked fire, 30 parts of American rosin F and 150 parts of pale paraffine oil and stir in 10 parts of single rectified rosin oil.

II.—Dark.—Melt 100 parts of anthracene oil and 20 parts of American rosin F on a slow fire. Next stir in 2 parts of Para rubber solution (or solution of caoutchouc waste) and keep on boiling until all is dissolved. When this is done there should be still added 5 parts of crude concentrated carbolic acid and 5 parts of zinc chloride lye, 50° Bé., stirring until cool. The last-named admixture is not absolutely necessary, but highly advisable, owing to its extraordinary preservative and bactericidal properties.

III.—Colored.—For red, melt 100 parts of coal-tar oil, then stir in 50 parts of pale paraffine oil, and finally 75 parts of bole or iron minium, and pass through the paint mill. Although the addition of iron minium is very desirable, it is considerably more expensive. For gray, proceed as above, with the exception that metallic gray is used in place of the bole. For green, metallic green is employed. The colors are identical with those used in the manufacture of roof varnish. To increase the antiseptic properties of the colored carbolineum, any desired additions of phenol or zinc chloride solutions may be made, but the chief requirement in the case of colored carbolineum is good covering power of the coating.

Paints for Roofs Covered with Tar Paper, for Roofing Paper, etc.—

I.—	Distilled coal tar	70 parts
	Heavy mineral oil (lubricating oil)	10 parts
	American rosin	20 parts
II.—	Distilled coal tar	50 parts
	Trinidad asphalt	15 parts
	Mineral oil, containing paraffine	10 parts
	Dry clay, finely ground	25 parts

Imitation Oil Paint.

Paints, Stains, Etc., For Ships.

Anti-fouling Composition.

	By weight
White lead, ground in oil	2 parts
Red lead, dry	1 part
Raw linseed oil	14 parts

While hot stir in yellow ocher, kaolin, baked clay in powder, or any inert body, such as silica, barytes, gypsum, etc., to form a stiff dough, and, without allowing this compound to become cold (the vessel should not be removed from the source of heat), dilute with more or less manganese linoleate to the required consistency.

Marine Paint To Resist Sea Water.

Dry white lead, carbonate only	1 part
Litharge	1 part
Linseed oil (fluid measure)	14 parts

Heat these and stir until of the consistency of thick glue, and for every 36 parts, by weight, of this compound add 3 parts, by weight, of turpentine, and 1 part, by weight, of mastic varnish (mastic rosin dissolved in turpentine); reheat the whole, and for every 32 parts, by weight, stir in and mix the following:

Baked and powdered clay	4 parts
Portland cement	16 parts
Zinc white	1 part
Red lead	1 part

After well mixing, dilute with more or less turpentine (not exceeding 25 per cent of the whole), or linoleate of manganese, the latter being preferable, as it has greater binding power. For colored paints use red oxide of iron or green oxide of chrome, but do not use chrome green or lead, as they will not stand the action of the sea water.

Compositions For Ships’ Bottoms.—

Green.
Pale rosin	25 pounds
Prepared mineral green	8 pounds
D. L. zinc	13 pounds
Boiled oil	2 pounds
Mineral naphtha	1 gallon
Petroleum spirit	1 ¹/₂ gallons
Prepared Mineral Green.
Dry levigated mineral green	28 pounds
Turpentine	7 pounds
Turpentine varnish	7 pounds
Refined linseed oil	7 pounds
Copper Color.
Pale rosin	25 pounds
Light Italian ocher	15 pounds
D. L. zinc	5 pounds
Turkey red paint	¹/₂ pound
Petroleum spirit	1 ¹/₂ pounds
Mineral naphtha	1 pound
Pink.
Pale rosin	25 pounds
D. L. zinc	16 pounds
Deep vermilion	7 pounds
Mineral naphtha	1 gallon
Petroleum spirit	1 ¹/₂ gallons

Paints For Walls Of Cement, Plaster, Hard Finish, Etc.

Coating For Bathrooms.

Cement, To Paint Over Fresh.

Damp Walls, Coating For.

Facade Paint.

This coating is very solid, can be washed, and is not injured by hydrogen sulphide.

Hard-finished Walls.

Paints, Waterproof And Weatherproof:

Water- and Acid-resisting Paint.

Water- and Air-proof Paint.

Paints For Wood:

Floor Coating.

Durable House Paint.

II.—Prime with zinc white and let this be succeeded by a coating with zinc chloride in glue water (size). The zinc oxide forms with the zinc chloride an oxy-chloride of great hardness and glossy surface. By admixture of pigments any desired shade may be produced. The zinc coating is indestructible, dries quickly, does not peel, is free from the smell of fresh oil paint, and more than 5 per cent cheaper.

Ivory Coating For Smooth, Light Wood.

Now painting with this milky substance may be commenced, using a fine hair pencil of excellent quality. The pencil is not dipped in the large bottle; but a glass is kept at hand with an opening of about 1 inch, so as to be able to immerse the pencil quickly. The substance is not flowing like the alcohol lacquers, for which reason it may be put on thick, for the ether, chiefly constituting the mass, evaporates at once and leaves but a very thin film which becomes noticeable only after about 10 such applications have been made. Shake the bottle well each time before filling the small glass, as the heavy Krems white is very apt to sink to the bottom of the bottle. If it is observed that the substance becomes too thick, which may easily occur on account of the evaporation, a part of the remaining ether is added, to which in turn 30 to 40 drops of oil are added, shaking it till the oil appears to be completely dissolved.

The operator must put on the mass in quick succession and rather thick. After about 10 coats have been applied the work is allowed to rest several hours; then 3 or 4 coats of pure collodion, to which likewise several drops of oil have been added, are given. Another pause of several hours having been allowed to intervene, application of the mass is once more begun.

When it is noticed that a layer of the thickness of paper has formed, the articles, after drying thoroughly, should be softly rubbed off with very fine glass paper, after which they require to be wiped off well with a clean linen rag, so that no dust remains. Then coating is continued till the work seems serviceable.

A few applications of pure collodion should be made, and when this has become perfectly hard, after a few hours, it can be rubbed down with a rag, {501} tripoli, and oil, and polished by hand, like horn or ivory. This work can be done only in a room which is entirely free from dust. The greatest cleanliness must be observed.