A practical treatise on the fabrication of volatile and fat varnishes, lacquers, siccatives, and sealing-waxes

Front matter

THE GETTY CENTER LIBRARY

A

PRACTICAL TREATISE

Contents

I. Introduction.

page

Classification of Lacquers and Varnishes ... 28

Section II

Preparation of Stains to be used in the Art of Varnishing and Lacquering. Mahogany Stains ....

Mahogany Stains continued.

Red Stains; Purple Stain ......

Red Stain for Horn, Ivory, and Bone; Purple Stains for

Horn, Ivory, and Bone.

Bright Red Stain for Horn, Ivory, and Bone ; Bright Red Stain for Bone and Ivory; Red Stain for Leather Cochineal Stain for Leather; Scarlet Stain for Leather ; Purple Stain for Leather ......

Crimson Stain ; Black Stains for Wood ....

Runge’s Chrome Ink as a Black Stain for Wood; Aliza¬ rine Ink as a Black Stain for Wood ....

Black Stain for Horn; Finest Black Stain for Horn ; Black Stain for Leather .....

Blue Stains .......

Another Receipt; Blue Stain of Elder-berries for Leather; Blue Stain for Wood .....

Blue with Aniline; Yellow Stains ; Yellow Stains for Wood ........

Yellow Stain for Horn ; Yellow Stain for Leather .

Bright Yellow Stains for Leather.

CONTENTS.

XIX

PAGE

Yellow Stain from Weld ; Yellow Stain for Wood . 295

Bright Goklen-Yellow Stain; Golden-Yellow Stains for Bone and Ivory ........ 296

Green Stain for Wood ; Green Stain for Horn, Ivory, and Bone ; Green Stains for Leather . . . .297

Green Stains for Wood, Horn, Ivory, Bone, and Leather 298 Tortoise-shell Stain for Horn ; Brown Stains for Leather 299 Hirschberg’s Stain for Walnut; Walnut Stain for Soft Wood ......... 300

Violet Stain for Leather ...... 301

Section IV. Art of Lacquering and Varnishing; General Buies . 302

Pumicing and Priming ; Laying on the Color . . 304

Pumicing the Paint; Varnishing ..... 305

Pumicing Lae-Varnishes ; Polishing Lae-Varnishes . 307

Materials used in Pumicing in the Art of Lacquering; Varnishing of Wooden Articles, Carriages, and Furni¬ ture .......... 308

Examination of the Article; Soaking with Linseed-Oil

Varnish ; Puttying ; Laying on the Priming Coat . 309

Pumicing the Ground; Ground Coat (DisguiseCoat) and its Application . . . . . . . .310

Pumicing the Disguise Coat; Laying on the Principal Color; Pumicing the Principal Paint . . . . 311

Decorating and Striping; Laying on the Varnish . . 312

Pumicing and Polishing; The Last Coat of Varnish; Varnishing of Furniture, Cases, Instruments, etc. ; Wooden Articles to be Varnished .... 313

XX

CONTENTS.

Sizing for Mixing the Color.

Priming Coat of Oil Paint; Yeining .

Colors for Oak, Curled Maple, Walnut, Rosewood, and Mahogany......

Articles of Tin and Metal which arc to be Lacquered Articles of Iron and Steel, Copper, Brass, and Zinc;

Colors used in Lacquering the above-named wares Preparation of the Colors—Black, Brown, Red, Green . Yellow, Chamois, Blue, Marble Ground, Tortoise-shell Ground . . . ,

Rosewood Ground; Decorations with Copperplates and Lithographs ....

Bronze Painting ; Lacquering of Leather Simple I rocess of Removing a Coat of Lacquer, etc., from Tinned Metal Plate .

Appendix

Japanese and Chinese Lacqueks.

Japanese Lacquers ....

Names of these Lacquers

Pigments, acids used ......

Baron Yon Ransonnet on the Application of Japanese Yarnishes .......

Japanese Fluid Lacquers ....

Chinese Lacquers ......

PAGE

Index .

. 335

PRACTICAL TREATISE

ON THE

FABRICATION OF VARNISHES, LACQUERS, ETC.

i.

Introduction

By lacquers and varnishes we understand fluids which, in a short time after they have been laid on an article, undergo such a change as to leave a color¬ less, or, at least, only faintly colored coating behind; though, of course, there are varnishes which have been colored intentionally. This coating has a smooth, glossy surface, and serves either for embellishing the article thus coated, or for protecting it against out¬ ward influences.

A good lacquer or varnish, when once applied, should dry quickly, and form a uniform layer of con¬ siderable thickness and bright lustre ; it should pre¬ serve these properties for a long time, should neither break nor crack, and should possess sufficient elasti¬ city to allow the varnished or lacquered article (tor 3 instance, wood or leather) to be bent to a certain ex¬ tent without cracking the coating.

The old civilized races of Eastern Asia, the Hindus, Chinese, but particularly the Japanese, are masters of the art of manufacturing varnishes and lacquers. Especially the last-named nation occupies such a high rank in this art, that, speaking without prejudice, we must admit that in this respect they are far in advance of us. We have seen Japanese lacquer-work at the International Exhibition at Vienna, in 1873, and a still larger display in Paris in 1878, which, on account of the excellent quality of the lacquer, attracted the attention of all judges of such things.

But it is by no means our opinion that these nations surpass the Europeans in chemical knowledge of the manufacture of lacquers and varnishes ; just the re¬ verse, in this respect we may be rather their teachers, but next to the conscientious labor which marks all Japanese work, we attribute the excellent quality of their products to the raw materials they use. They have at their command oils and resins furnished to them from the rich treasury of vegetable products of the tropics, materials, many of which we do not know at all, but which seem to be especially adapted for the fabrication of varnishes and lacquers. We believe we do not speak erroneously when we express the opinion that the stock of materials for the manufacture of lacquers and varnishes will be substantially increased before long from Japan, as it is well known that at the

INTRODUCTION.

present time the country is being opened up more and more to the Europeans.

We know of few products of the chemical industry which find such universal use as lacquers and var¬ nishes. They are absolutely indispensable to the me¬ chanic as well as to the artist. We only need call to mind that the wood of our floors and furniture, many articles of leather, our carriages, the component parts of iron bridges, and other articles of metal exposed to the weather, are varnished or lacquered for the pur¬ pose of giving them a pleasing appearance or to pro¬ tect them against the weather; we would further remind the reader that the painter, the gilder, the mechanic, the photographer, in short all those engaged in the art of manifolding articles require varnish or lacquer in one form or another for their purposes.

In the following pages we have endeavored to de¬ scribe the fabrication of all kinds of varnishes and lacquers in such a manner as to be easily understood by all. Whatever chemical processes are treated of, we have explained the nature of these processes in such a way that even those who have received no in¬ struction in this highly important science can easily comprehend it.

As varnishes and lacquers and the substance to which the name of sealing lacquer has been given, are closely related to each other, and as both industries can be very well carried on together, we have added to this work a treatise on the fabrication of the dif¬ ferent kinds of sealing lacquer and sealing wax.

Classification of Lacquers and Varnishes.

We cannot draw a sharp line of distinction between varnishes and lacquers. By varnishes we generally understand certain fat oils which, by proper chemical treatment, have acquired the property of hardening in a short time to a transparent mass when they are exposed to the air in thin layers. The term lacquer is generally given to solutions of different kinds of gum or resin, dissolved in proper solvents, and when these become hard when exposed to the air, the dis¬ solved resin is either held inclosed by the solvents or the latter simply evaporate and leave the dissolved substance behind.

As the first group of lacquers is prepared with fat oils, they are called fat or oil varnishes. The oil varnishes are without doubt the most valuable pro¬ ducts of our branch of industry, because, besides possessing considerable hardness and bright lustre, they are more durable and possess a greater power of resistance than other kinds of lacquers or var¬ nishes.

Those kinds of lacquer in which the gum or resin is dissolved by a volatile solvent are usually called spirit varnishes, because formerly, besides oil of turpentine, spirit of wine was exclusively used as a solvent. But, as in the present state of our industry this term is no longer a proper one, we consider it necessary to desig¬ nate these kinds of lacquers as volatile lacquers. Be¬ sides ethylic alcohol (spirit of wine or alcohol in com-

INTRODUCTION.

mon language) methylic alcohol (wood-spirit), benzine, petroleum, naphtha, and many other volatile sub¬ stances are used as solvents.

According to what has already been said, we may divide varnishes and lacquers into several groups, namely: —

1. Fat oil varnishes obtained by a chemical change of certain oils of vegetable origin, the so-called drying oils.

2. Fat or oil lacquers obtained by dissolving differ¬ ent kinds of gum or resin in the above named fat dry¬ ing oils.

3. Volatile lacquers or varnishes , prepared by dis¬ solving different kinds of gum in volatile fluids, such as oil of turpentine, ethylic alcohol, methylic alcohol, ethylic ether, benzine (by benzol or benzine we under¬ stand certain volatile fluids which are obtained by dis¬ tilling coal tar, and the terms benzol or benzine are to be understood in this sense in the following pages), and naphtha.

Although it is absolutely necessary that every manufacturer should have a thorough knowledge of the raw materials used in his branch of industry, yet for two reasons this seems to be doubly necessary for the manufacturer of lacquers and varnishes; for, on the one hand, the quality of the products depends in a higher degree on the choice of the proper raw mate¬ rials than is the case in any other industry ; and, on the other, because the elementary materials we have

3* to use are frequently brought into the market adulte¬ rated in an almost incredible manner.

In view of the last-named circumstance we would advise every manufacturer to procure the necessary chemicals from well known manufacturers only, and to buy the raw materials from firms of good standing, but especially the foreign gums and resins, as they are very frequently adulterated on account of their costli¬ ness.

But as it is always of the utmost importance for every one to be able to form for himself a decisive judgment as to the quality of the raw products, we have briefly mentioned in the following chapter of this work, which treats of the raw materials, the physical and chemical characters of all the materials, and in doing this we believe we have rendered a service to every manufacturer.

II. Raw Materials, Used In The Fabrication Of Lacquers And Varnishes

The raw materials used in our industry are so nu¬ merous that we must endeavor to find some practical classification. First, the nature of the materials them¬ selves furnishes such a classification, namely, fluid and solid raw materials. The fluid raw materials are either non-volatile or volatile ; the solid raw materials are

RAW MATERIALS.

either natural products or products of chemical in¬ dustry.

Using this as a basis of our classification we can now proceed to a description of the different raw materials.

Fluid Raw Materials.

A.— Non-volatile.

Fat , Non-drying Oils.

Of these the following are used in the manufacture of lacquers and varnishes: hemp oil, pumpkin oil, lin¬ seed oil, grape-seed oil, poppy oil, nut oil, and castor oil. But only a few of those mentioned are used to any large extent, and linseed oil occupies the foremost place in this respect.

B.— Volatile.

Essential Oils and Chemical Products.

Acetone, ether, camphor, benzol, wcod spirit, petro¬ leum, naphtha, sulphuret of carbon, oil of turpentine, tar oil, spirit of wine.

Solid Raw Materials.

A.— Natural Products.

Crums and Resins , Wax.

The numerous substances belonging to this group are mostly of vegetable origin, though some of them are also derived from the mineral kingdom, and only one from the animal kingdom. The following are of special importance :—

Asphaltum, amber, benzoin, colophony, capal, dam¬ mar, elemi, gutta percha, caoutchouc, mastic, sandarac, shellac, turpentine, wax.

Pigments .— Coloring Matter.

Aniline colors, turmeric, curcuma, dragon’s blood, gamboge, indigo, lampblack, seed lac, saffron, sanders wood.

B.— Chemical Products.

Compounds of lead: protoxide of lead (litharge), acetate of lead (sugar of lead), red oxide (red lead, or minium). Compounds of manganese: pyrolusite (peroxide of manganese), permanganate of potassium, borate of manganese, etc. Compound of zinc: oxide of zinc (flowers of zinc, or zinc-white). Mineral tar oil, refined paraffin, hard caoutchouc.

III. Drying Oils

In conformity with their chemical properties, the drying oils must be classed with the large group of combinations known under the general term of fats. But as the drying oils form the basis of the fabrication

DRYING OILS.

of lacquers and varnishes, we consider it necessary to devote a somewhat larger space to the explanation of these bodies, so as to give those who possess no chem¬ ical knowledge an insight into those points to which special attention has to be paid in our branch of industry.

Fats in general are combinations consisting, as far as their combinations are concerned, of a so-called base and several acids. As chemists designate com¬ binations of a base and acids by the general term of salts, we may say: fats are salts containing several acids. The base of most fats, and also of drying oils, is an oily body, having a pungent, sweetish taste. This, in a refined form, is found in commerce, as a much used toilet article, under the name of glycerine. Generally three acids are found in fats, namely: stearic acid, palmitic acid, and oleic acid ; the first two of these form the material from which the so-called stearin candles are manufactured. In their purest state they represent foliated, colorless crystals, which melt only at a temperature of over 60° C. (140° F.). Oleic acid is always an oily, thick, mostly yellowish colored fluid, of a strongly acid character, and is used for cleansing metals, but especially for manufacturing soap.

Most fats, therefore, consist of combinations of gly¬ cerine Avith stearic, palmitic, and oleic acid. These combinations are called glycerides, and, according to the predominance of tristearin, tripalmitin, or triolein in these combinations, the fats are divided into tallow, butter, and lard (fixed fats), and into oils (fluid fats).

When any one of these fats is exposed to the air for any length of time, it undergoes a considerable change in regard to its properties: the formerly colorless and tasteless mass acquires a very disagreeable odor, and strongly acid taste ; at the same time it assumes a darker color, and the formerly fluid fats become viscid. Ibis change in the fats produced by a certain compo¬ nent part of the air (fats from which the air is entirely excluded do not undergo such a change) is called ran¬ cidity. But we would draw special attention to the fact that a fluid fat always remains fluid; it may be¬ come more viscid , but it never congeals to a solid mass, even if it is exposed for years to the influence of the atmosphere. It is this property which forms the only actually recognizable boundary line between the dry¬ ing and non-drying oils ; as the drying oils possess the property of changing under the influence of the air in a short time into solid masses having a resinous ap¬ pearance.

In many oils this change takes place in a few hours, especially when the oil is brought in contact with a large quantity of oxygen, that is, when it is exposed to the air in a very thin layer. Such oils are classed as good drying oils, and are especially adapted for the fabrication of lacquers and varnishes. But, on the other hand, those oils requiring days, weeks, or even months for drying in, are called bad drying oils, and

DRYING OILS.

the longer the time they require for drying in the less value they possess for our purposes.

The process of drying in does not take place in such a manner that the oil congeals to a hard mass at a cer¬ tain moment, but by coming in contact with the air it thickens more and more, and gradually passes from a fluid into a solid state. But as of course this trans¬ formation also takes place when drying oils are exposed in an open vessel to the influence of the air for any length of time (but the vessel should be protected from dust falling into it by a frame covered with blotting-paper),.thus already introducing the drying process into the oil, this will explain the reason why, for in¬ stance, old linseed oil is dearer than that which has been pressed recently. The first by having been in contact with the air for a considerable time has been already transformed to such an extent that, when it is spread out in a thin layer in this condition, it may be actually called a kind of varnish, as in a very short time it will form a solid, coherent mass ; but the latter must be either stored for a long time, or has to undergo a special treatment to acquire the property of drying quickly.

There are certain bodies of the nature of acids which give to the drying oils the property of solidify¬ ing: into hard masses. One of these acids which has been examined and studied most thoroughly is the one found in linseed oil, the so-called linoleic acid. Now as linseed oil is the most important of all drying oils, we may take it as a sample of drying oils, and from its behavior study that of all others, and what will here be said about the changes linseed oil undergoes when exposed to atmospheric influence, holds good almost to the letter in regard to all other genuine dry¬ ing oils.

When linseed oil is exposed to the air in a vessel protected against the falling in of dust, we perceive that the oil undergoes a gradual change as far as its physical qualities are concerned; it assumes a darker color, becomes more viscid and less inflammable. At the same time a steadily progressing increase of weight will be noticed, which, according to our special expe¬ riments, made as to this subject for a year and a half, may amount to fully 8 per cent. An experiment made for this purpose xvith 100 grammes (3.5 ozs. avoird.) of the best Bavarian linseed oil gave an in¬ crease of weight of 8.98 grammes (0.31 oz. avoird.) after the oil had been exposed to the air for eighteen months.

All the drying oils consist of combinations in which are contained the elementary bodies: Carbon C, 1 hy¬ drogen H, and oxygen 0. Now accurate experiments have shown that the drying oils absorb a large quan¬ tity of oxygen from the air, and in return liberate a certain quantity of carbonic acid (C0 2 ) and water (II 2 0) in the form of vapor; the carbon C, and hy¬ drogen II, originate from the oil, the oxygen from the

1 The added letters are symbols used in chemistry for repre¬ senting these elementary bodies.

DRYING OILS.

air. The origination of every combination of any ele¬ mentary body with oxygen is called in chemistry combustion or oxidation. In one part of the com¬ ponents of the drying oils oxidation progresses so far that no more oxygen can be absorbed, they are com¬ pletely oxidized to carbonic acid and water, which escape into the air; in another part oxidation pro¬ gresses only so far as to form combinations which contain a larger amount of oxygen than those which were previously present, and, therefore, become more viscid.

According to what has been said above, the changes the drying oils suffer from a continued contact with oxygen, can be briefly expressed as follows:—

The drying oils absorb from the air a quantity of oxygen amounting to as much as 8 per cent, of the weight of the oil, which completely oxidizes a part of the carbon and hydrogen contained in the oils, to car¬ bonic acid and water, and with the remaining compo¬ nents produces viscid combinations, which finally be¬ come solid by a still further progressing absorption of oxygen.

It is a well-known fact that differently colored light produces chemical effects of different powers. Now, comparative experiments have proven that an entire absence of light is a most unfavorable condition for the absorption of oxygen, but that a green light is the most favorable. It would, therefore, appear to be advisable to keep linseed oil, not in barrels, but in bottles of common green glass.

As will be explained more fully later on, it is pos¬ sible to accelerate the absorption ot oxygen by the drying oils by using certain chemicals, and it is this operation which is actually carried on in boiling the varnish. According to the investigations of excellent chemists, it is not actually necessary to boil the drying oils for them to acquire the property of drying quickly, that is to change into varnish.

It is a well-known fact that the fat oils, the unctuous non-drying, as well as the drying oils, are usually gained by subjecting the vegetable parts in which they are found to a strong pressure. In consequence of the very high pressure used for this purpose, many other substances, such as vegetable fibres, vege¬ table gum, and vegetable albumen, become mixed with the oil, which have to be removed by so-called re¬ fining.

Refining is generally done by treating the raw oil with sulphuric acid, which does not change the oil but destroys all other substances which are separated in a carbonous mass, and give a black color to the oil. After the oil has become clear it is drawn off from the sediment, and freed from the adhering sulphuric acid by treating it with water. According as the refining process has been carried on with more or less care, the oil will contain fewer or more foreign substances. But it is just these foreign substances which injure the power of the oils to dry quickly when exposed to the air, and it has, therefore, been proposed to treat the oils with substances dissolved in water, which possess

DRYING OILS.

the property of forming insoluble, quickly separating combinations with the above-named bodies (vegetable gum and vegetable albumen). Linseed oil refined in this manner did in fact dry to a perfectly solid mass in thirty hours after it had been applied on a glass plate. In speaking of linseed oil we will return to this important phenomenon.

Linseed Oil.

Linseed oil is obtained from the seed of the flax (Linum usitatissimum ), which is raised in large quan¬ tities, especially in the more temperate countries of Europe. The seed contains more than 28 per cent, of oil, hut at the utmost only 26 to 27 per cent, can he gained. Fine linseed oil is always obtained by pressing it at an ordinary temperature—cold pressing; by heating the pressed mass to the boiling point of water—hot pressing—a larger percentage of oil can he obtained, but it is always inferior in quality to the cold-pressed oil.

Cold-pressed linseed oil has a very light-yellow color, very little hut a peculiar taste and odor; the hot-pressed oil has a much darker color, golden yellow to amber, and the peculiar taste and odor of the oil are much stronger and more disagreeable.

Good linseed oil should always be of light-yellow color, should have but little odor, and when rubbed upon a glass plate should feel sticky to the touch within a few hours.

The lighter the color of a varnish or lacquer is, the more valuable is the product, but no colorless varnish can be manufactured with ordinary linseed oil, be its color never so light a yellow. But it is possible to bleach the linseed oil by various processes in such a manner that it represents a perfectly colorless fluid clear as water.

Bleaching of Linseed Oil.

Bleaching with a solution of Green Vitriol .—10 kilogrammes (22 lbs.) of the oil to be bleached are placed in bottles holding from 15 to 16 liters (4 to 4.2 gals.), and 4 to 5 liters (4.2 to 5.2 quarts) of a solution of green vitriol are added to every quantity of oil. The solution of green vitriol is prepared by dissolving 100 kilogrammes (220 lbs.) of green vitriol in 160 liters (42.2 gals.) rain water. The bottles are placed in a light room in such a manner that the}’ are exposed as much and as long as possible to the direct rays of the sun. Every bottle should be well shaken at least once a day. It takes from three to six weeks to perfectly bleach the oil. The length of time will depend on the temperature, but especially on the stronger or weaker effect of the rays of the sun. The clear oil is then poured off carefully from the solution of green vitriol, and kept in glass bottles. The solu¬ tion of green vitriol can be used several times for the same purpose. Should it have lost somewhat of its strength, it can be made effective again by adding 10 kilogrammes of green vitriol to 100 liters (26.4 gals.) of the fluid.

DRYING OILS.

Bleaching with sulphuric acid is done in a similar manner to that which has been explained in refining the oils in general, but the oil is not washed suffi¬ ciently to remove every trace of sulphuric acid, as lead colors prepared with such linseed oil offer a greater resistance to the after-darkening than such as have been prepared with oil entirely free from acid.

Bleaching with Sulphate of Lead .—Sulphate of lead is a white, insoluble powder, which can easily be prepared by a combination of sulphuric acid with ace¬ tate of lead (sugar of lead). For the purpose of bleaching linseed oil with this preparation, two per cent, of the mass of oil is taken and rubbed intimately together with a little oil upon the grinding-stone. This mixture is then thinned down to the consistency of milk and added to the linseed oil which in this case must also be placed in bottles exposed to the light. The turbid fluid clarifies slowly, and in a few weeks the oil will be found perfectly clear and bleached. The foreign substances which were contained in the oil lie in a tolerably solid skin-like mass over the sediment of sulphate of lead, which can be used quite often for the same purpose.

On account of its great commercial value linseed oil is frequently adulterated. When oils of less value are added, it is very difficult to detect such an adul teration, and it can only be discovered by an accurate determination of the density. It is easier to detect an addition of common resin with which the oil is fre quently adulterated. To detect such an adulteration

4 * the oil is shaken with a double quantity of strong spirit of wine, which dissolves the resins hut the oil does not mix with it. If a few drops of a solution of acetate of lead are added to this solution, a strong flocky precipitate will be formed at once, if resin should be present in the oil. If the fluid remains clear after the solution of acetate of lead has been added, it is a proof that no resin is contained in the oil.

Hemp Oil

is gained by cold and hot pressing from the seeds of the hemp plant (Cavmabis sativa). It has a light yel¬ lowish-green color, but only as long as it is fresh ; old oil becomes gradually darker, and finally assumes a dull-brown color. Generally hemp oil does not dry as well as linseed oil, but it can be very well used for varnishes, especially for those purposes where its dark color will be no hindrance.

Poppy Oil

is obtained in considerable quantities from the small, black seed of the common poppy plant (Papaver somniferum). The seeds are so rich in oil that more than one-half their weight can be gained from them. Poppy oil has a light-yellow color, and on account of its mild, agreeable taste, is frequently used for culinary pur¬ poses. In the fabrication of lacquers and varnishes it is only used for fine qualities. It is also used by artists for thinning their colors.

DRYING OILS.

Nut Oil.

This oil is obtained from the fruit of the common walnut tree (Juglans regia). The cold-pressed oil differs essentially from that which is obtained later on by using heat. The first is nearly colorless, or at least only slightly yellowish-green, and when fresh has a very pleasant odor and taste ; when exposed to the light it becomes perfectly bleached in a short time. Hot-pressed oil is highly colored, and has a rather disagreeable taste and odor. For this reason hydrau¬ lic presses are only used for pressing the oil, as these produce the greatest pressure .of all presses. As cold-pressed oil commands a higher price, the manufacturers endeavor to obtain the highest pressure by the most powerful presses, so as to be able to gain the greatest part of the oil by cold pressing.

On account of its very light color it is much liked for the fabrication of very fine varnishes, and also for thinning colors used in oil painting.

Other Drying Oils

are grape-seed oil, cotton-seed oil, pumpkin oil, etc., but so far they have been generally but little used, and are scarcely known at all in the fabrication of varnishes. But as the oils mentioned above can be produced in large quantities and at very low prices, we have made experiments with them, as, if they are properly treated, they furnish very well drying var¬ nishes. As the bleaching of these oils is a very tedious labor, it seems tt> us advisable to use them for such varnishes as do not require to be of a very light color. In consequence of the continual rise in the prices of oils, it seems to' us very important to call attention to these oils, as by using them the manufacturer will be enabled to place in the market products of the second and third qualities at a very low price.