Some of the acid reds, e.g., Acid Magenta, Acid Violet, belong (p. 105) to the group of sulphonated basic dyes. The vast majority belong to the group of azo dyes, which can be employed to dye from palest pinks to the deepest crimson reds. Some dye very brilliant shades, others only yield dull reds. Some dye shades remarkable for their fastness to all agencies, soap, acids, alkalies, light and air; others dye shades which may be fast to soap, but loose to acids and light. Generally even shades are readily obtained on any kind of woollen fabric. It is practically impossible to name all the acid reds that are known and that may be used, but a fairly representative series of recipes will be given.

Ponceau.—Wet out, then prepare a bath with 2 lb. Ponceau R, 10 lb. Glauber's salt, 2 lb. sulphuric acid. Enter the wool in the cold, bring to a boil and work to shade, wash and dry.

Crushed Strawberry.—Prepare a bath containing 10 lb. Glauber's salt, 4 oz. Scarlet R S, 9 oz. Indigo extract, 2 oz. Orange Y, 4 oz. sulphuric acid. Enter wool at 160 deg. F., give four turns, raise temperature slowly to a boil, and turn to shade, lift and wash.

Scarlet.—Prepare a dye-bath with 2 lb. Azo cochineal, 10 lb. Glauber's salt, 4 lb. sulphuric acid. Work at the boil until the full shade is obtained, then lift, wash and dry.

Terra Cotta Red.—The dye-bath is made from 2-1/2 lb. Fast Acid Magenta B, 2-1/2 lb. Fast Yellow F Y, 10 lb. Glauber's salt, 2 lb. sulphuric acid. Work at the boil to shade.

Fast Scarlet.—Prepare a dye-bath with 3 lb. Glauber's salt, 1-1/4 lb. sulphuric acid, 2-1/2 lb. Brilliant Scarlet 4 R. Work at the boil for one and a half hours.

Scarlet.—Make the dye-bath with 2 lb. Scarlet 2 R J, 10 lb. Glauber's salt and 2 lb. sulphuric acid. The goods may be entered at about 150 deg. F., and the temperature raised at the boil and maintained at that heat for one hour, then the goods are lifted, rinsed and dried.

The method given in the above recipes is that usually followed (p. 106) with the acid colours. When closely woven or thick goods are being dyed, where it is desired that the colour should penetrate well into the substance of the goods, the following modification of working may be adopted:—

The dye-bath is made up with the dye-stuff and Glauber's salt only, and the goods are worked in this at the boil until they are thoroughly impregnated with the dye-stuff liquor, then the acid is added in small quantities at a time, and the dyeing is continued for one hour to fix the colouring matter on the wool fibre. The goods may then be lifted out, washed and dried.

Scarlet.—Make the dye-bath with 2 lb. Scarlet F R, 10 lb. Glauber's salt and 2 lb. sulphuric acid. In place of scarlet F R, the F 2 R or F 3 R brands may be used, the latter giving the reddest shades.

Scarlet.—Make the dye-bath with 2 lb. Scarlet O O, 10 lb. Glauber's salt and 2 lb. sulphuric acid. Scarlet O dyes a yellower shade of scarlet, while scarlets O O and O O O dye slightly redder shades.

Scarlet.—The dye-bath is made with 3 lb. Brilliant Ponceau 2 R, 10 lb. Glauber's salt and 10 lb. bisulphate of soda. This gives a brilliant shade of scarlet. Brilliant Ponceau G, used in the same way, gives a much yellower tone of scarlet, the R gives a slightly yellower tone, while the 3 and 4 R brands dye redder shades.

Bluish Red.—The dye-bath is made with 2 lb. Brilliant Croceine B, 10 lb. Glauber's salt, and 10 lb. bisulphate of soda. Brilliant croceine B B and the brand M dye redder shades of scarlet.

Red.—Make the dye-bath with 3 lb. Milling Red R, 20 lb. Glauber's salt, and 5 lb. acetic acid. This is a good bright shade, and is quite fast to soaping and milling.

Deep Scarlet.—Dye with 3 lb. Chromotrop R, 10 lb. Glauber's (p. 107) salt, and 2 lb. sulphuric acid. This scarlet is very fast to milling, acid and light.

Red.—Make the dye-bath with 2 lb. Victoria Scarlet R, 1 lb. Victoria Rubine O, 10 lb. Glauber's salt, and 4 lb. sulphuric acid. A fine deep scarlet red is obtained.

Scarlet.—Dye with 2 lb. Brilliant Orseille C, 10 lb. Glauber's salt, and 3 lb. sulphuric acid. This gives a bright bluish shade of scarlet.

Red.—Dye with 1 lb. Emin Red and 5 lb. bisulphate of soda.

Scarlet.—Make the dye-bath with 3 lb. Croceine Scarlet 3 R, 10 lb. Glauber's salt, and 2 lb. sulphuric acid.

Fawn Red.—Make the dye-bath with 1-1/2 oz. Cyanole, 1-1/2 oz. Orange extra, 2-1/2 oz. Archil Substitute N, 10 lb. Glauber's salt, and 2 lb. sulphuric acid. This gives a nice light tint of fawn red, of a somewhat bluish tone.

Deep Fawn Red.—A very deep shade of fawn red is dyed with 4-1/2 oz. Cyanole, 2-1/4 lb. Orange extra, 1-1/4 lb. Archil Substitute N, 10 lb. Glauber's salt, and 2 lb. sulphuric acid. The same dye-stuffs are used as in the last, but the result is a deeper shade, of a yellow tone.

Crushed Strawberry Red.—Use 4 oz. Chromotrop 2 R, 2 oz. Cyanine B, 1 oz. Azo yellow, 10 lb. Glauber's salt, and 2 lb. sulphuric acid.

Pale Lilac Rose.—Dye with 1 oz. Chromotrop 2 R, 1/2 oz. Cyanine B, 1/2 oz. Azo yellow, 10 lb. Glauber's salt, and 2 lb. sulphuric acid.

Deep Fawn.—Dye with 3-1/4 oz. Chromotrop 2 R, 1-1/2 oz. Orange G, 2 oz. Cyanine B, 4 oz. Fast Acid Blue R, 10 lb. acetic acid, and 20 lb. Glauber's salt.

Crimson.—Make the dye-bath with 3 lb. Titan Red 6 B, 20 lb. salt, with a little acetic acid, and work at the boil. This gives a fine shade of crimson, fast to acids and capable of standing milling very well.

Deep Crimson.—A bright and deep crimson is dyed with 4 lb. Fast (p. 108) Acid Magenta B, 10 lb. Glauber's salt, and 3 lb. sulphuric acid, working at the boil.

Pale Crimson.—Make the dye-bath with 2 lb. Fast Acid Magenta B, 10 lb. Glauber's salt, and 2 lb. sulphuric acid, working at the boil. Level shades are readily obtained, and the dye is fast to washing.

Deep Crimson.—Make the dye-bath with 4 lb. Azo Fuchsine G, 10 lb. Glauber's salt, and 2 lb. sulphuric acid. This gives a very deep shade of crimson, of a bluish tone.

Bluish Crimson.—Use in the dye-bath 2 lb. Azo Fuchsine G, 10 lb. Glauber's salt, and 2 lb. sulphuric acid.

Pale Bluish Crimson.—Use in the dye-bath 1 lb. Azo Fuchsine G, 10 lb. Glauber's salt, and 2 lb. sulphuric acid. This gives a very bright shade of pale crimson. The B brand of the Azo Fuchsines gives slightly bluer shades than the above.

Deep Crimson.—A very solid crimson is dyed in a bath containing 3 lb. Azo Red A, 2 oz. Orange extra, 2 oz. Cyanole extra, 10 lb. Glauber's salt, and 2 lb. sulphuric acid. Work at the boil.

Bright Crimson.—A fine bluish crimson can be dyed on wool with 4 lb. Azo Red A, 10 lb. Glauber's salt, and 10 lb. bisulphate of soda. Work at the boil.

Deep Crimson.—A good shade can be dyed with 6 lb. Amaranth, 10 lb. Glauber's salt, and 10 lb. bisulphate of soda, working at the boil.

Brilliant Pale Bluish Crimson.—A really brilliant shade, bordering on a violet red, is dyed in a bath containing 1-1/2 lb. Fast Acid Violet R, 10 lb. Glauber's salt, and 2 lb. sulphuric acid.

Bluish Crimson.—Make the dye-bath with 3 lb. Croceine Scarlet, 10 lb. Glauber's salt, and 2 lb. sulphuric acid. This gives a good full shade of a bluish tone and very bright.

Bluish Crimson.—Dye with 3 lb. Chromotrop 6 B, 10 lb. Glauber's salt, and 3 lb. sulphuric acid. This gives a fine tint, (p. 109) very fast to acids, milling and light.

Purple.—Make the dye-bath with 3 lb. Chromotrop 10 B, 10 lb. Glauber's salt, and 3 lb. sulphuric acid.

The Chromotrops are remarkable for the fulness of the shades they dye, the brightness of their tint, and their fastness to acids, washing and light.

Purple.—Use 4 lb. Azo Fuchsine B, 10 lb. Glauber's salt, and 2 lb. sulphuric acid.

Bluish Purple.—A very dark shade of purple is dyed with 4 lb. Azo Acid Violet 4 R, 10 lb. Glauber's salt, and 2 lb. sulphuric acid.

Bordeaux Reds.—These are shades that lie intermediately between the scarlets and the crimsons. They are in general duller than the scarlets, and have a more solid and fuller look; while they are less blue in tone than the crimson. They can be obtained from a large variety of dye-stuffs, and the recipes given below may be regarded as typical examples.

Bright Bordeaux Red.—Make the dye-bath with 1 lb. Azo Bordeaux, 10 lb. Glauber's salt, and 2 lb. sulphuric acid, working at the boil to shade. This is a very bright shade, of a somewhat bluish tone.

Cherry Red.—Make the dye-bath with 2-1/2 lb. Fast Acid Magenta B, 2-1/2 lb. Fast Yellow, 10 lb. Glauber's salt, and 2 lb. sulphuric acid. This gives a fine deep shade.

Bright Cherry Red.—A very yellow shade of red, fast to milling, is dyed by making a dye-bath with 1-1/2 lb. Anthracene Yellow C, 3 lb. Diamine Fast Red F, 10 lb. Glauber's salt, 5 lb. acetate of soda, and 2 lb. bisulphate of soda. Work at the boil for one hour, then lift, add 3 lb. fluoride of chrome, re-enter the wool and work half an hour longer; wash and dry.

Deep Bordeaux Red.—The dye-bath is made with 4 lb. Diamine Fast Red F, 5 lb. acetate of soda, and 3 lb. bisulphate of soda. Work (p. 110) at the boil for one hour, then lift, add to the bath 3 lb. fluoride of chrome, re-enter the goods and work again for half an hour; lift, wash and dry.

Bright Cherry Red.—Make a dye-bath with 4 lb. Benzo Fast Red, 10 lb. Glauber's salt, and 2 lb. acetic acid. Work at the boil for one hour, then lift, add 3 lb. fluoride of chrome, re-enter the goods and work for half an hour longer; wash and dry.

Cherry Red.—Make the dye-bath with 2 lb. Azo Fuchsine G, 1-1/2 lb. Fast Yellow, 10 lb. Glauber's salt, and 2 lb. sulphuric acid. Work at the boil for one hour.

Bluish Bordeaux Red.—For a very fast shade use 8 oz. Fast Acid Violet R, 8 oz. Orange G, 3/4 oz. Patent Blue B, 10 lb. Glauber's salt, and 2 lb. sulphuric acid. Work at the boil for one hour.

Bright Bordeaux Red.—A good bright and fast shade of red is dyed with 3-1/2 lb. Emin Red and 7 lb. bisulphate of soda. Work at the boil for one hour, then lift, add 3 lb. fluoride of chrome, work for three-quarters of an hour, then lift, wash and dry.

Bordeaux Red.—Use 3 lb. Titan Scarlet D, 1/4 lb. Titan Brown O, and 20 lb. salt. Work at the boil for one hour, then lift, wash and dry.

Claret Reds.—Claret reds are very useful shades and are great favourites of the dress-loving public. They are dark reds of a yellow tone, and can be dyed upon wool in a variety of ways, of which the following recipes just indicate a few.

Claret.—Make the dye-bath with 4 lb. Milling red R, 10 lb. Glauber's salt, and 4 lb. sulphuric acid.

Claret.—Use 4 lb. Archil Substitute N, 10 lb. Glauber's salt, and 2 lb. sulphuric acid.

Claret.—Make the dye-bath with 2 lb. Bordeaux B L, 10 lb. Glauber's salt, and 2 lb. sulphuric acid.

Claret.—A deep shade is dyed with 2-1/2 lb. Victoria Scarlet R, (p. 111) 2 lb. Victoria Rubine O, 1 oz. Cyanine Scarlet R, 2 lb. Victoria Rubine O, 1 oz. Cyanine B, 10 lb. Glauber's salt, and 2 lb. sulphuric acid.

Claret.—A fine deep shade is dyed with 2 lb. Azo Red A, 1/4 lb. Orange extra, 1/4 lb. Cyanole, 10 lb. Glauber's salt, and 2 lb. sulphuric acid.

Maroon Reds.—From clarets to maroons is not a wide interval, they are both dark shade reds, the former tending to a yellow tone, the latter to a more bluish shade of red. A few recipes will be given to show some of the best methods of dyeing maroons.

Maroon.—Use 6 lb. Amaranth B, 10 lb. Glauber's salt, and 2 lb. sulphuric acid. This gives a fine bright shade.

Deep Maroon.—Make the dye-bath with 4-1/2 lb. Fast Acid Violet 10 B, 80 lb. Glauber's salt, and 3 lb. sulphuric acid. This gives a fine blue shade of maroon of great depth.

Maroon.—The dye-bath is made with 3 lb. Azo acid violet 4 R, 1 lb. Fast Yellow S, 1-1/2 oz. Fast Green Bluish, 10 lb. Glauber's salt, and 2 lb. sulphuric acid.

Deep Maroon.—Make the dye-bath with 2 lb. Acid Magenta, 1/2 lb. Orange O, 1/2 lb. Patent Blue V, 10 lb. Glauber's salt, and 2 lb. sulphuric acid.

Deep Maroon.—Make a dye-bath with 3 lb. Azo Acid Rubine, 1-1/2 oz. Acid Black B B, 10 lb. Glauber's salt, and 2 lb. sulphuric acid.

Maroon.—The dye-bath is made with 3 lb. Milling Red B, 1-1/2 oz. Naphthol Black 4 R, 10 lb. Glauber's salt, and 3 lb. sulphuric acid.

Deep Maroon.—Make the dye-bath with 1-1/2 lb. Victoria Scarlet R, 13 oz. Victoria Rubine O, 1/2 lb. Victoria Yellow, 2 lb. Keton Blue G, 10 lb. Glauber's salt, and 3 lb. sulphuric acid.

Bright Red.—A good shade is dyed with 4 lb. Lanafuchsine S G, and 10 lb. bisulphate of soda. Lanafuchsine S B dyes somewhat bluer shades.

Fast Red.—Dye with 4 lb. Milling Red B, 10 lb. Glauber's salt, (p. 112) and 2 lb. sulphuric acid.

Bright Scarlet.—Dye with 3 lb. Brilliant Cochineal 2 R, 10 lb. Glauber's salt, and 3 lb. sulphuric acid.

Deep Scarlet.—Dye with 3 lb. Brilliant Ponceau 4 R, 10 lb. Glauber's salt, and 2 lb. sulphuric acid.

Pinks.—Pink.—Use 1-1/2 oz. Erythesine D, and 5 lb. acetic acid. These two pinks are very much alike and are very bright.

Bluish Pink.—Use 1-1/2 oz. Rose Bengale and 5 lb. acetic acid.

Pink.—Make the dye-bath with 3 oz. Azo Cochineal, 10 lb. Glauber's salt, and 2 lb. sulphuric acid.

Bluish Pink.—Make the dye-bath with 3/4 to 1 oz. Fast Acid Violet R and a little Orange G, 10 lb. Glauber's salt, and 2 lb. sulphuric acid.

Pink.—By using 1-1/2 oz. Fast Acid Violet R, 3/4 oz. Orange G, 10 lb. Glauber's salt, and 2 lb. sulphuric acid, a good full pink is obtained.

Bluish Pink.—Use 2 oz. Fast Acid Violet R, 10 lb. Glauber's salt, and 2 lb. sulphuric acid.

Many of the other acid reds may be used for dyeing pinks if from 2 to 4 oz. of dye-stuff be used.

Pink.—Use in the dye-bath 1-1/2 oz. Diamine Fast Red F, 5 lb. acetate of soda, and 3 lb. bisulphate of soda.

Coral Red.—Make the dye-bath with 1/2 lb. Diamine Scarlet B, 10 lb. Glauber's salt, and 1 lb. acetic acid.

Dark Cherry Red.—The dye-bath is made with 2-1/2 lb. Orange G G, 1 lb. Brilliant Orseille C, 3/4 oz. Cyanole extra, 10 lb. Glauber's salt, and 2 lb. sulphuric acid.

Deep Crimson.—Use in the dye-bath 4 lb. Brilliant Orseille C, 1-1/2 oz. Cyanole extra, 3 oz. Orange G G, 10 lb. Glauber's salt, and 2 lb. sulphuric acid.

Scarlet.—Make the dye-bath with 4 lb. Lanafuchsine S G, and 10 lb. bisulphate of soda. Work at the boil to shade.

Crimson.—Make the dye-bath with 4 lb. Lanafuchsine S B, and (p. 113) 10 lb. bisulphate of soda. Work at the boil to shade.

The Lanafuchsines, of which there are three brands, S G, S B, and 6 B, dye very good level shades of red from scarlet to crimson, which are of good fastness to milling, acids and light.

Salmon.—Use 1/2 lb. Rhodamine B, 1/4 oz. Naphthol Yellow S, 10 lb. Glauber's salt, and 2 lb. acetic acid.

Rose Red.—Use 1/4 lb. Lanafuchsine S B, 3 oz. Lanafuchsine S G, 10 lb. Glauber's salt, and 1 lb. sulphuric acid.

Salmon Red.—Use 1-1/2 oz. Lanafuchsine S G, 1/4 oz. Fast Yellow S, 10 lb. Glauber's salt, and 1/2 lb. sulphuric acid.

Deep Crimson.—The dye-bath is made with 2 lb. Naphthol Red C, 9 oz. Acid Magenta, 3/4 oz. Cyanole extra, 10 lb. Glauber's salt, and 2 lb. sulphuric acid.

Purple Red.—Dye with 2-1/2 lb. Naphthol Red C, 3/4 lb. Acid Magenta, 1 oz. Cyanole extra, 10 lb. Glauber's salt, and 2 lb. sulphuric acid.

Bordeaux Red.—Dye with 4 lb. Lanafuchsine S B, 1 oz. Orange extra, 10 lb. Glauber's salt, and 2 lb. sulphuric acid.

Fawn Red.—Dye with 1/4 lb. Orange G G, 3 oz. Lanafuchsine S B, 1/2 oz. Cyanole extra, 10 lb. Glauber's salt, and 2 lb. sulphuric acid.

Salmon.—Prepare the dye-bath with 1/4 oz. Fast Acid Violet R, 1/2 oz. Orange G, 10 lb. Glauber's salt, 1 lb. sulphuric acid. Work at the boil to shade.

The mordant reds are fairly numerous, and include both natural and artificial red dye-stuffs. The principle or property on which the application of this group of dye-stuffs to the dyeing of textile fabrics depends is that they are of an acid character and combine with metallic oxides, like those of iron, aluminium, or chromium to form insoluble coloured bodies, or "colour lakes" as they are called. The shade or tint of these colour lakes depends, firstly, upon the (p. 114) dye-stuff, and, secondly, upon the metallic oxide. Thus Alizarine with alumina gives a scarlet, with chrome a dark red, and with iron a dull violet. Alumina and chrome are the metallic mordants most commonly used in the dyeing of reds; sometimes tin is used, but never iron.

The coal-tar colour makers have placed at the service of dyers a great variety of mordant dyes, which may be classified somewhat roughly into groups, according to their chemical composition. The first group is called phenolic colours. These contain the group, or radical OH, hydroxyl, once or oftener. It is to the presence of this group that they owe their acid character and the property of combination with metallic oxides. To this group of dye-stuffs belong such dyes as Alizarine, Alizarine Cyanine, Anthragallol, Gambine, Coerulein, and some others. The natural red dye-stuffs, Cochineal, Brazil-wood, madder, etc., probably belong to this class.

None of these are essentially dyes of themselves, and used alone will not dye any fibre, it is only when they are brought into combination with the mordant that they will dye the wool fibre.

The next group may be called hydroxy-azo dyes, and are quite of modern introduction. They are azo dyes, one of whose constituents is a body like salicylic acid, amido-benzoic acid, dihydroxy-naphthalene-sulpho acid, which contain the group OH, hydroxyl with carboxyl COOH. The first group imparts phenolic characters, while the second gives true acid properties, and both of these acting together cause the dyes to be able to form colour lakes with metallic oxides. There is one point of difference between the two groups of dyes, the phenolic dyes are as a rule not dyes of themselves, some of them are practically free from colour, and it is only when brought into combination with the metallic oxide or mordant that they form a colour and dye a fibre. On the (p. 115) other hand the azo mordants are in general colouring matters, and can be used to dye wool without the aid of a mordant, the latter only serving to make the colour faster to light, acids, milling, etc., and it often has no material effect on the shade or tone of colour being dyed. Alizarine Yellow G G, Gambine Yellow, Anthracene Yellow, Chrome Violet, are examples of such dyes.

There are, however, some dyes (such as the Chromotrops, Azofuchsine, Anthracene Acid Browns, etc.) on which the mordant has a marked effect.

The methods adopted in practice for the application of this class of dyes are many and varied. The mordants used are alum, alumina sulphate, acetate of chrome, chrome alum, fluoride of chrome, ferrous sulphate and tin chloride, while, in addition, along with these true mordanting materials, assistant mordants are used, such as argol, tartar, tartaric acid, lactic acid, lignorosine, oxalic acid and sulphuric acid.

The mordanting may be done either before or after the dyeing, the first plan being that commonly adopted with the phenolic colours, while the second method may be used and is the best to use with azo-mordant dyes. Sometimes the mordanting and dyeing may be done in one bath, but this method is one which leads to a loss of colouring matter and often to the production of colours which are loose to rubbing, and cannot, therefore, be recommended.

Mordanting.—This operation is carried out in the same way in all cases. The goods are entered into the bath at a temperature of about 150 deg. F. The heat is raised to the boil, and is then maintained for one and a half hours, after which the mordanted wool is lifted and well rinsed, when it is ready for the dye-bath. As mordanting materials bichromate of potash and fluoride of chrome are chiefly used when chrome mordants are required, sometimes chrome alum. With these (p. 116) are used sulphuric acid, oxalic acid, cream of tartar or argol, lactic acid, etc.

Which of these are used depends entirely on the results which are to be got and the dye-stuff to be used, more particularly is this the case when bichromate of potash is the mordanting material. When sulphuric acid is used as the assistant along with the bichrome, then there is formed on the wool fibre a deposit of chromic acid and chromium oxide, and this exerts an oxidising effect on the colouring matter or dye-stuff, which in some cases, as the Alizarine Blue, Alizarine Yellow, etc., leads to a destructive effect, and, therefore, the production of weak shades, so that it is not possible always to use an oxidising mordant. When tartar, argol, oxalic acid, lactic acids and other assistants of an organic nature are used, then a different effect is obtained, the bichromate is completely decomposed, and a deposit of chromium oxide formed on the wool. This does not exert any action on the colouring matter, and hence this mordant is known as the non-oxidising mordant. It may be pointed out that when wool is mordanted with potassium or sodium bichromate and sulphuric acid (oxidising mordant) it has a deep yellow colour, while when mordanted with bichromate or other chrome salt, and the organic assistants enumerated above (non-oxidising mordant), it has a green colour, and one sign of a well-mordanted wool is when it has a good bright tone free from yellowness.

Of the organic assistants tartar is undoubtedly the best in general use, and, although slow in its action, leaves a good deposit of oxide of chrome on the wool in a suitable condition to develop the best results on dyeing. Argols are only an impure tartar. They can only be used when dark shades are to be dyed. Oxalic acid does not work as well as tartar, and there is not so much chrome oxide deposited on the wool, while there is a slight tendency for a small proportion of this to be in the form of chromic acid. Of late years lactic acid and (p. 117) lignorosine have been added to the list of assistant mordants; both these give excellent results, they lead to a more complete and more uniform decomposition of the bichromate, and therefore the mordanting baths are more completely exhausted, so that rather less bichromate is required; the shades which are obtained are in general fuller and brighter. Examples of the use of these assistants will be found among the recipes given below.

With fluoride of chrome either oxalic acid or tartar is used, and a deposit of chromium oxide is formed on the wool, the general effect being the same as when bichromate of potash is used with oxalic acid or tartar.

Alumina is applied either in the form of alum or of sulphate of alumina, argol or tartar being used as the assistant, oxide of alumina being deposited on the fibre.

When ferrous sulphate (copperas) is used then tartar is almost invariably used as the assistant mordant, oxalic acid only rarely.

The dyeing with mordant dyes must be done in a special way and with great care, if uniform, level shades and fast colours are to be obtained.

The dye-bath must be started cold, and the wool be entered and worked for twenty to thirty minutes, the object being to cause the dye-stuffs to penetrate well into the substance of the fibre, then the temperature is slowly raised to the boil, not less than three-quarters of an hour being taken in doing so; the temperature is maintained at the boil for fully one and a half hours longer. During the boiling operation the mordant and dye-stuff combine together, and form the characteristic colour lake, and the boiling fixes this firmly on to the wool.

The water used plays a very important part. If too hard in character, the lime it contains shows a tendency to combine with the (p. 118) dye-stuff and form a colour lake, which is deposited in a loose form on the wool or in the bath, tending to make the shades dull and loose to rubbing. This defect can be remedied by adding a little acetic acid to the dye-bath, say about 3 lb. to 100 gallons of the water. It combines with and neutralises the influence of the lime, in so far as the formation of a loose colour lake is concerned; still the lime does unite with the dye-stuff, but the combination is formed more slowly, and in or on the wool fibre so that it is fast.

By working in the manner laid down above very fast shades can be dyed on wool with mordant dyes, and the following recipes will give the other details as to tints, shades, quantities, etc., not noted above.

Claret.—Mordant, 2 lb. bichromate of potash and 2 lb. tartar; dye, 8 lb. Alizarine Claret R.

Fawn.—Mordant, 3 lb. bichromate of potash and 1-1/2 lb. tartar; dye, 3 lb. Alizarine Orange N.

Maroon.—Mordant, 3 lb. bichromate of potash and 2-1/2 lb. tartar; dye, 15 lb. Alizarine Orange N.

Deep Crimson.—Mordant, 3 lb. bichromate of potash and 2-1/2 lb. tartar; dye, 8 lb. Alizarine Red 1 W S.

Lilac Rose.—Mordant, 1-1/2 lb. bichromate of potash and 1-1/2 lb. tartar; dye, 1 lb. Alizarine Red 1 W S.

Crushed Strawberry Tint.—Mordant, 2 lb. bichromate of potash and 1-1/2 lb. tartar; dye, 3 lb. Alizarine Red 2 W S.

Deep Claret.—Mordant, 3 lb. bichromate of potash and 2-1/2 lb. tartar; dye, 5 lb. Alizarine Red 1 W S.

Bright Fawn Red.—Mordant, 2 lb. bichromate of potash and 1-1/2 lb. tartar; dye, 1 lb. Alizarine Red 5 W S.

Scarlet.—Mordant, 10 lb. alum and 6 lb. tartar; dye, 4 lb. Alizarine Red 5 W S.

Rose.—Mordant, 6 lb. alum and 4 lb. tartar; dye, 1 lb. Alizarine Red 1 W S.

Deep Scarlet.—Mordant, 10 lb. alum and 6 lb. tartar; dye, (p. 119) 4 lb. Alizarine Red 1 W S.

Deep Maroon.—Mordant, 3 lb. bichromate of potash and 1 lb. sulphuric acid; dye, 5 lb. Alizarine Red 3 W S.

Bright Maroon.—Mordant, 3 lb. bichromate of potash and 2 lb. tartar; dye, 5 lb. Alizarine Red S W, 10 lb. Mordant Yellow.

Deep Fawn Red.—Mordant, 3 lb. bichromate of potash and 2-1/2 lb. tartar; dye, 10 lb. Alizarine Orange W and 1 lb. Mordant Yellow.

These typical recipes are here given to show what tints may be obtained from the alizarine and the quantity of dye-stuffs required. By using other proportions of dye-stuffs than those given a variety of other tints may be dyed.

The method of working described above is applicable to other mordant dyeing colours besides the alizarine reds, such as Alizarine Orange, Alizarine Blue, Anthracene Brown, Alizarine Cyanine, Galloflavine, Gambine, Chrome Violet, etc. It will therefore not be required to repeat this description of the process when the use of mordant colours for producing other colours, such as blues, navies, drabs, browns, etc., is dealt with.

Although the shades dyed with the alizarines and allied colouring matters are lacking in the brilliance characteristic of the azo scarlets, yet they have the very great advantage of being quite fast to washing, acids and light.

There is another method of using those alizarine reds that are sold in the form of powder, and which are distinguished by the letter S. They are of some value in dyeing heavy woollen cloths, and the method is indicated in the two recipes which follow:—

Brilliant Scarlet.—Prepare a dye-bath with 20 lb. Glauber's salt and 4 lb. Alizarine Red 1 W S, boil the wool in this for three-quarters of an hour; then lift, add to the same bath 4 lb. (p. 120) sulphuric acid, again work at the boil for three-quarters of an hour; then lift, add 10 lb. alum, re-enter the goods, and work three-quarters of an hour longer; then lift, wash and dry.

Claret.—Prepare a bath with 20 lb. Glauber's salt and 4 lb. Alizarine Red 1 W S, boil for three-quarters of an hour; then lift, add 4 lb. sulphuric acid, re-enter the wool, boil for three-quarters of an hour; then lift, add 3 lb. bichromate of potash, re-enter the wool, and boil for three-quarters of an hour longer; then lift, wash and dry.

Bluish Red.—Mordant, 2 lb. bichromate of potash and 2 lb. lactic acid; dye, 2 lb. Alizarine Red S. In this recipe there is used lactic acid as the assistant, and a very fine shade results.

Red.—Mordant, 3 lb. lignorosine, 2 lb. bichromate of soda and 1 lb. sulphuric acid; dye with 12 lb. Alizarine Orange 2 G.

Dark Bordeaux Red.—Mordant, 3 lb. lignorosine, 3 lb. bichromate of soda and 1-1/2 lb. sulphuric acid; dye, 12 lb. Alizarine S X.

Dark Red.—Mordant, 3 lb. lignorosine, 2-1/2 lb. bichromate of soda and 1-1/4 lb. sulphuric acid; dye, 6 lb. Alizarine Orange 2 G and 4 lb. Alizarine S X.

Lignorosine used as the assistant mordant in the above recipes works very well, and gives bright shades.

Fast Bordeaux.—Prepare a bath with 4 lb. Chromogene I, 1-1/2 lb. Alizarine Red 1 W S, 1 lb. Alizarine Red 5 W S, 1/2 lb. Fast Acid Violet R, 10 lb. Glauber's salt and 3 lb. sulphuric acid. Work at the boil for one hour, then lift; add to the same bath 3 lb. bichromate of potash and 1-1/2 lb. sulphuric acid. Re-enter the goods and work to shade, then lift, wash and dry.

Terra Cotta.—Make a dye-bath of 30 lb. Fustic, 8 lb. Turmeric, 30 lb. Sanders and 10 lb. Sumac. Boil the goods in this for one (p. 121) hour, then add 3 lb. sulphate of copper, previously dissolved in water, boil for one hour; cool, sadden with Copperas, using about 3-1/2 lb. or less if required; then rinse and dry.

Another method is to mordant the goods at a boil for one and a half hours in 2 lb. bichromate of potash and 2 lb. tartar. Drain and wash. Dye in a fresh bath with 8 lb. sanders and 10 lb. fustic; afterwards sadden with 1/4 lb. copperas; allow to stand one hour; wash and dry.

ORANGE SHADES ON WOOL.

With Direct Dyes. Make a dye-bath with 2 lb. Titan Orange, 20 lb. Glauber's salt, and 1/2 lb. acetic acid. Work at the boil for one and a half hours, then lift, wash and dry.

Bright Orange.—Dye with 1-1/2 lb. Benzo Orange R, 10 lb. salt, and 1 lb. acetic acid, working at the boil for one hour.

Orange.—Dye with 2 lb. Chloramine Orange, 20 lb. salt, and a little acetic acid, working at the boil for one hour.

Orange.—Dye with 2 lb. Diamine Orange G C, and 20 lb. Glauber's salt.

Pale Orange.—Dye with 3 lb. Diamine Gold, 10 lb. Glauber's salt, and 5 lb. ammonium acetate.

Reddish Orange.—Dye with 3 lb. Diamine Orange D C and 20 lb. Glauber's salt.

Orange.—Dye with 2 lb. Diamine Scarlet B, 1 lb. Thioflavine S, and 20 lb. Glauber's salt.

Dark Orange.—Dye with 1 lb. Diamine Red 5 B, 1 lb. Thioflavine S, and 20 lb. Glauber's salt.

With Acid Colours. Orange.—Dye with 2 lb. Ponceau 3 G, 10 lb. Glauber's salt, and 2 lb. sulphuric acid.

Bright Orange.—Dye with 2 lb. Mandarine G, 10 lb. Glauber's salt, and 2 lb. sulphuric acid.

Orange.—Dye with 2 lb. Croceine Orange, 10 lb. Glauber's salt, and 2 lb. sulphuric acid.

Bright Orange.—Use 3 lb. Orange G G, 10 lb. Glauber's salt, and (p. 122) 2 lb. sulphuric acid, boiling for one hour.

Orange.—Use 3 lb. Orange R, 10 lb. Glauber's salt, and 2 lb. sulphuric acid. Work at the boil. Orange Extra will give a slightly less red tone of orange, Croceine orange gives a good bright shade of a yellowish tone.

There are several brands of Orange dyes which can be used; they differ but little in shade from one another. In general they give fast colours. The Tropaeolines also dye orange shades, but they are not so fast as the other dyes which have been named.

Gold Orange.—Make a dye-bath with 1/2 lb. Diamine scarlet B, 2 lb. Anthracene Yellow C, 50 lb. Glauber's salt, 5 lb. acetate of ammonia. Enter the wool, work for half an hour, then add 3 lb. bisulphate of soda. Boil again for half an hour, then lift. Add 3 lb. fluoride of chrome, re-enter the wool, boil again for half an hour, then lift, wash and dry. This gives a very fast orange.

With Mordant Dyes. Old Gold.—Mordant with 3 lb. bichromate of potash and 1 lb. sulphuric acid; dye with 6 lb. Alizarine Yellow R W.

Pale Orange.—Mordant with 6 lb. alum and 4 lb. tartar; dye with 1 lb. Alizarine Orange G G.

Deep Orange.—Mordant with 10 lb. alum and 6 lb. tartar; dye with 10 lb. Alizarine Orange N. This last dye-stuff gives a slightly redder shade of Orange than does the Alizarine Orange G.

Deep Orange.—Dye in a bath with 1-3/4 lb. Azo Alizarine Orange R R, 10 lb. Glauber's salt, and 2 lb. sulphuric acid, and fix in the same bath with 1 lb. bichromate of potash.

Orange.—Dye in a bath with 1 lb. Alizarine Red 1 W S, 2 lb. Mordant Yellow O, 10 lb. Glauber's salt, and 2 lb. sulphuric acid, then fix with 1-1/2 lb. bichromate of potash.

Orange.—Dye in a bath with 1 lb. Anthracene Red, 2 lb. (p. 123) Alizarine Yellow, 10 lb. Glauber's salt and 2 lb. sulphuric acid. After dyeing fix with 2 lb. fluoride of chrome.

Gold Orange. Mordant with 3 lb. bichromate of potash, and 2 lb. tartar, for one and a half hours at the boil; rinse. Then dye in a new bath with 1 lb. Alizarine Orange, 17 lb. Fustic extract. Work at 100 deg. F. for half an hour, then heat gradually to the boil and dye for one and a half hours at that temperature; lift, rinse and wash.

Olive Yellow on Worsted Yarn.—Mordant the yarn by boiling for one hour or one and a half hours in a bath of 3 lb. bichromate of potash; then dye in a bath of 1-1/2 lb. Gambine Yellow and 10 lb. of fustic chips.

Red and orange form a kind of group of colours which shade off one into the other almost imperceptibly by using a range of dyes such as Croceine A Z, Brilliant Croceine 9 B, Brilliant Croceine 7 B, Brilliant Croceine 5 B, Brilliant Croceine 3 B, Brilliant Croceine M O O, Crystal Scarlet 6 R, Brilliant Cochineal 4 R, Brilliant Croceine B, Brilliant Cochineal 2 R, Orange E N Z, and Croceine Orange E N. It is possible to dye shades from a scarlet crimson to a bright orange.

YELLOW SHADES ON WOOL.

The number of yellow dye-stuffs is very great, and the variety of tints infinite. Yellow may be dyed with both natural and artificial dye-stuffs, and the recipes given will include examples showing the use of both kinds. Speaking generally, yellow dye-stuffs include amongst them some of the fastest colours known, and there is a larger proportion of fast yellow colouring matters than of any other class of dye-stuffs.

With Acid Yellows. Bright Yellow.—Make the dye-bath with 1 lb. Fast Yellow F Y, 10 lb. Glauber's salt, and 2 lb. sulphuric acid, working at the boil to shade.

Olive Yellow.—Prepare the dye-bath with 1 lb. Azo Carmine, (p. 124) 1-1/2 oz. indigo carmine, 1/2 lb. Fast Yellow, 10 lb. Glauber's salt, and 2 lb. sulphuric acid, working at the boil to shade.

Maize Yellow.—Prepare a dye-bath with 5 lb. acetate of ammonia, 3 oz. Anthracene Yellow C, 1/4 oz. Diamine Fast Red F. Work for twenty minutes at the boil, then add 3 lb. bisulphate of soda; work half an hour longer, and then wash and dry.

Bright Canary.—Prepare a dye-bath with 4 lb. bisulphate of soda, 1/2 lb. Nitrazine Yellow. Heat the bath to about 120 deg. F., enter the goods and heat up to the boil, and work till the bath is exhausted, then lift; add to the dye-bath 3 lb. alum, 3 lb. tin spirits; re-enter the goods, and boil for twenty minutes longer; lift, wash and dry.

Bright Straw.—Dye with 3 oz. Phenoflavine and 20 lb. bisulphate of soda.

Straw.—Make the dye-bath with 1-1/4 oz. Azo Yellow, 1 dr. Cyanine B, 1 dr. Chromotrop 2 R, 10 lb. Glauber's salt, and 1 lb. sulphuric acid.

Greenish Straw.—Dye with 1/4 oz. Cyanine B, 1 oz. Victoria Yellow, 1/4 oz. Chromotrop 2 B, 10 lb. Glauber's salt, and 1 lb. sulphuric acid.

Olive Yellow.—Mordant with 3 lb. bichromate of potash and 1 lb. sulphuric acid; dye with 3 lb. Milling yellow O and 1 lb. acetic acid.

Bright Yellow.—A good shade is dyed in a bath of 2 lb. Milling yellow O, 10 lb. Glauber's salt, and 2 lb. sulphuric acid, working at the boil.

Olive Yellow.—Dye with 1-1/2 lb. Titan Yellow R, 10 lb. common salt, and 1 lb. acetic acid; after the colour has fully gone on to the wool, add to the bath 1-1/2 lb. fluoride of chrome and maintain at the boil for half an hour; then lift, wash and dry.

Deep Yellow.—The dye-bath is made with 1-1/2 lb. Titan (p. 125) Yellow R, 10 lb. common salt, and 1 lb. acetic acid, working at the boil to shade.

Yellow.—A good shade is dyed with 1-1/2 lb. Titan Yellow Y, 10 lb. common salt, and 1/2 lb. acetic acid, working at the boil to shade.

Golden Yellow.—Mordant with 3 lb. bichromate of potash and 2 lb. tartar; dye with 1 lb. Anthracene Yellow C.

Deep Golden Yellow.—Make the dye-bath with 3 lb. Anthracene Yellow C, and 3 lb. bisulphate of soda. Work at the boil for half an hour, then lift; add 3 lb. fluoride of chrome, re-enter the wool and work at the boil for another half-hour, then wash and dry.

Deep Olive Yellow.—Mordant with 3 lb. bichromate of potash and 2 lb. tartar; dye with 20 lb. fustic extract. This gives a very deep shade of olive Yellow.

Bright Lemon Yellow.—Make the dye-bath with 10 lb. Gambine Yellow, 7 lb. alum, and 2 lb. oxalic acid. Enter cold, then slowly heat to the boil and work to shade; then lift, wash and dry.

Leaf Yellow.—Mordant with 3 lb. bichromate of potash and 1/2 lb. sulphuric acid; then dye with 2 lb. Gambine Y and 1 lb. Yellow N.

Deep Leaf Yellow.—A somewhat deeper shade than the last is dyed by first mordanting with 2 lb. bichromate of potash and 1/2 lb. sulphuric acid, then dyeing with 2 lb. Gambine R and 1 lb. Yellow N.

Lemon Yellow.—Prepare a bath with 40 lb. fustic, 6 lb. alum, 6 lb. tartar, and 3/4 lb. tin crystals; enter the wool and work at the boil for one and a half hours, then lift, wash and dry.

Olive Yellow.—Mordant, 3 lb. bichromate of potash and 2 lb. tartar; dye, 3 lb. extract of fustic.

Deep Lemon.—Mordant, 3 lb. bichromate of potash and 2 lb. tartar; dye, 1 lb. Alizarine Yellow G G W.

Golden Yellow.—Mordant, 3 lb. bichromate of potash and 1 lb. (p. 126) sulphuric acid; dye, 10 lb. Alizarine Yellow G G W.

Light Straw.—Make the dye-bath with 3 oz. Anthracene Yellow B N, 5 lb. acetate of ammonia, and 3 lb. bisulphate of soda; work at the boil to shade, then lift, wash and dry.

Old Gold.—A very fine shade of old gold is obtained by dyeing in a bath of 3 lb. Anthracene Yellow C, 5 lb. acetate of ammonia, and 3 lb. bisulphate of soda. Work at the boil for three-quarters of an hour, then lift; add to the dye-bath 3 lb. fluoride of chrome, re-enter the wool, and work for one and a half hours longer at the boil; lift, wash and dry.

Deep Yellow.—Mordant, 3 lb. bichromate of potash and 2-1/2 lb. tartar; dye, 2 lb. Mordant Yellow D.

Pale Olive Yellow.—Dye with 3 lb. Anthracene Yellow G G, 10 lb. Glauber's salt, and 2 lb. acetic acid; after the dye-bath is exhausted of colour add 3 lb. fluoride of chrome, and work at the boil half an hour longer.

Gold Yellow.—Dye with 3 lb. Anthracene Yellow B N, 10 lb. Glauber's salt, and 3 lb. acetic acid; after half an hour's boil, add 1-1/2 lb. bichromate of potash, work for half an hour longer.

Gold Yellow.—Dye with 2 lb. Indian Yellow R, 10 lb. Glauber's salt, and 2 lb. sulphuric acid.

GREEN SHADES ON WOOL.

Of green shades there is an infinite variety, and these can be dyed in several ways. Either a simple green dye-stuff may be used or mixtures of blue and yellow dye-stuffs may be employed, this latter method being extremely common. It is somewhat interesting to notice that, notwithstanding the great prevalence of green in Nature, the dyer has at his command no natural green dye-stuff, but must, if he prefers to adopt natural dye-stuffs, use a mixture of blue and yellow dye-stuffs to produce green shades. There are but few green colouring (p. 127) matters derived from coal tar: Gambine, Dinitroso-resorcine, Alizarine Green, Brilliant Green, Malachite Green, Azo Green, Fast Green, Naphthol Green, Acid Green, Diamine Green, Benzo Green almost exhaust the list. Compared with the numerous red and blue dyes which are obtained from coal-tar products, green dyes are conspicuous by their fewness. On the other hand, the dyer has in the blue and yellow dyes from coal tar a means of producing any tint or shade of green he may require.

Members of all the classes of basic, direct, acid, azo and mordant dyes, can be found among the dye-stuffs which can be used in dyeing green, and the methods and principles of their application have been fully described in previous pages. The following recipes contain all the practical information that is needed:—

With Direct Dyes. Dark Green.—The dye-bath is made with 1 lb. Titan Blue 3 B, 1 lb. Titan Yellow Y, 2 lb. salt, and 1/2 lb. acetic acid.

Bright Green.—Prepare a dye-bath with 1 lb. Titan Yellow G, 1 lb. Titan Blue 3 B, 20 lb. salt, and 1/2 lb. acetic acid, working at the boil for one hour.

Dark Green.—Make a dye-bath with 4 lb. Acid Blue 4 S, 2 lb. Titan Yellow Y, and 5 lb. acetate of ammonia, working at the boil to shade.

Blue Green.—Make the dye-bath with 6 lb. Acid Blue 4 S, 2-1/2 lb. Titan Yellow Y, and 5 lb. acetate of ammonia, working at the boil to shade.

Bottle Green.—The dye-bath is made with 5 lb. Acid Blue 4 S, 2-1/2 lb. Titan Yellow Y, and 5 lb. acetate of ammonia, working at the boil to shade. The greens shown in the last three recipes are of a very satisfactory character, and show how, by the use of acetate of ammonia in the dye-bath, the direct dyeing Titan colours can be combined with acid colours.

Green.—Make the dye-bath with 5 lb. Glauber's salt, 5 lb. (p. 128) acetate of ammonia, 2 lb. Sulphon Cyanine, and 1-1/2 lb. Chrysophenine.

Dark Green.—The dye-bath is made with 2 lb. Sulphon Cyanine, 3/4 lb. Chrysophenine, 5 lb. Glauber's salt, and 5 lb. acetate of ammonia.

Pale Russian Green.—Make the dye-bath with 1/2 lb. Sulphon Cyanine, 2-1/2 oz. Chrysophenine, and 10 lb. Glauber's salt.

The last three shades have the merit of being fast to milling, and fairly so to light.

Olive.—Make a dye-bath with 1 lb. Nyanza Black B, 1 lb. Chrysamine, and 20 lb. Glauber's salt. Work at the boil to shade, lift, wash and dry.

With Acid Dyes. Blue Green.—Make a dye-bath with 10 lb. Glauber's salt, 2 lb. sulphuric acid, 2 lb. Patent Blue N, and 1 lb. Azo Yellow, working at the boil.

Sage Green.—The dye-bath is made with 10 lb. Glauber's salt, 2 lb. sulphuric acid, 2 lb. Azo Yellow, and 1 lb. Patent Blue N, working at the boil.

Olive Green.—Make the dye-bath with 3 lb. Naphthol Green B, 10 lb. Glauber's salt, 15 lb. bisulphate of soda, and 1 lb. copperas, working at the boil to shade.

Bright Green.—Make the dye-bath with 10 lb. Glauber's salt, 5 lb. bisulphate of soda, and 1-1/2 lb. Acid Green B, working at the boil to shade.

Emerald Green.—The dye-bath is made with 1/2 lb. Acid Green B, 10 lb. Glauber's salt, and 2 lb. sulphuric acid. The wool might also be previously mordanted with 15 lb. hyposulphite of soda, and 5 lb. sulphuric acid at the boil for one and a half hours, when it will give a bright shade of emerald green.

Grass Green.—Dye a medium indigo bottom on the wool from the vat, then dye in a bath with 1 lb. Milling Yellow O, 5 lb. Glauber's salt, and 5 lb. bisulphate of soda; lift, wash and dry.

The last recipe shows the use of the indigo vat in giving the blue (p. 129) constituent in dyeing greens and other compound colours on wool. This, while being a very effective method of dyeing, yet necessitates two operations which add very materially to the cost of dyeing such shades, hence it is not used for dyeing low class woollen fabrics, but for better class goods it is frequently adopted, fast colours being thus obtained.

In thus using the indigo vat as a bottom dye regard to the properties of indigo must be paid in carrying out any subsequent dyeing operation, so that the indigo on the fibre be not destroyed. As a rule, the indigo will resist any ordinary baths made with Glauber's salt, acetate of ammonia, sulphuric or acetic acids, but it will not resist mordanting operations with bichromate of potash, for the latter salt destroys the indigo. Fluoride of chrome, chrome acetate, or alum, may be used as mordants if necessary.

Pale Sea Green.—The dye-bath contains 1 oz. Cyanine B, 1 oz. Azo Yellow, 5 lb. Glauber's salt, and 1 lb. sulphuric acid.

Moss Green.—The dye-bath is made with 1/2 oz. Chromotrop 2 R, 2 oz. Cyanine B, 4 oz. Fast Acid Blue R, 3-1/4 oz. Azo Yellow, 5 lb. acetic acid, and 10 lb. Glauber's salt.

Deep Moss Green.—Prepare the dye-bath with 4-1/2 oz. Cyanine B, 9 oz. Fast Acid Blue R, 4-1/2 oz. Azo yellow, 1/2 oz. Chromotrop 2 R, 5 lb. acetic acid, and 10 lb. Glauber's salt.

Blue Green.—A very fine shade of blue green is dyed with 9-1/2 oz. Cyanine B, 1-1/4 lb. Fast Acid Blue R, 4 oz. Azo Yellow, 5 lb. acetic acid, and 10 lb. Glauber's salt.

Emerald Green.—A pale, but brilliant shade of green is dyed with 1-1/4 oz. Patent Blue V, 4-1/4 oz. Azo Yellow, 10 lb. Glauber's salt, and 2 lb. sulphuric acid.

Bright Leaf Green.—Dye in a bath with 13 oz. Victoria Yellow, (p. 130) 1/2 lb. Patent Blue V, 1/2 oz. Chromotrop 2 R, 10 lb. Glauber's salt, and 2 lb. sulphuric acid.

Deep Leaf Green.—The dye-bath is made with 22 oz. Cyanine B, 1 lb. Azo Yellow, 2-1/2 oz. Chromotrop 2 R, 10 lb. Glauber's salt, and 2 lb. sulphuric acid.

Bright Peacock Green.—The dye-bath is made with 5 oz. Chromotrop 6 B, 4 oz. Patent Blue V, 7 oz. Azo Yellow, 10 lb. Glauber's salt, and 2 lb. sulphuric acid.

Dark Beige Green.—Make the dye-bath with 1/2 lb. Fast Green Bluish, 6 oz. Fast Yellow F Y, 4-1/2 oz. Azo Fuchsine G, 10 lb. Glauber's salt and 2 lb. sulphuric acid.

Invisible Green.—Make the dye-bath with 1-1/2 lb. Fast Green Bluish, 1-1/4 lb. Fast Yellow F Y, 1 lb. Azo Fuchsine G, 10 lb. Glauber's salt and 2 lb. sulphuric acid.

Pale Sage Green.—Make the dye-bath with 1 lb. Azo Acid Brown, 1/2 lb. Fast Acid Violet 10 B, 10 lb. Glauber's salt and 2 lb. sulphuric acid.

Bright Grass Green.—Make a dye-bath with 10 lb. Glauber's salt, 2 lb. sulphuric acid, 3/4 lb. Phenoflavine, 3/4 lb. Azo Carmine B, and 5-3/4 lb. extract of indigo.

Moss Green.—Prepare a dye-bath with 1 lb. Azo Acid Brown, 1/4 lb. Fast Acid Violet 10 B, 10 lb. Glauber's salt and 2 lb. sulphuric acid.

Dark Sage Green.—Make the dye-bath with 3 lb. Azo Acid Brown, 1/2 lb. Fast Acid Violet 10 B, 10 lb. Glauber's salt and 2 lb. sulphuric acid.

Emerald Green.—A fine shade of emerald green can be dyed in a bath which is made from 1/2 lb. Fast Green Bluish, 1 lb. Fast Yellow F Y, 1 lb. Acid Violet 6 B, 10 lb. Glauber's salt and 2 lb. sulphuric acid.

Bottle Green.—Make a dye-bath with 1-1/2 lb. Victoria Violet 8 B S, 3/4 lb. Victoria Yellow, 2 oz. Naphthol Yellow S, 1 oz. Fast Acid Violet R, 1/2 oz. Cyanine B, 10 lb. Glauber's salt and 2 lb. sulphuric acid. Work for one hour at the boil, then lift; add 3 lb. fluoride (p. 131) of chrome, re-enter the wool, and work for half an hour at the boil.

Pale Pea Green.—A fine bright shade is dyed in a bath containing 1-1/2 oz. Cyanole, 3/4 oz. Naphthol Yellow and 10 lb. bisulphate of soda. By increasing the quantity of dye-stuff in proportion to the material, fine deep shades of green can be dyed.

Deep Electric Green.—Make the dye-bath with 2 lb. Cyanole, 1 lb. Indian Yellow G and 10 lb. bisulphate of soda, working at the boil for one hour; then lift, wash and dry.

With Mordant Dyes. Green.—Mordant with 10 lb. alum, 1 lb. bichromate of potash and 16 lb. tartar. Dye with 10 lb. indigo extract, 2 lb. fustic extract and 3 lb. alum, working at the boil; lift, wash and dry.

Dark Green.—Mordant with 3 lb. bichromate of potash, 8 lb. alum and 3 lb. tartar. Dye with 10 lb. extract of indigo, 2 lb. extract of fustic and 3 lb. alum, working at the boil.

Sea Green.—Mordant with 3 lb. bichromate of potash and 2-1/2 lb. tartar at the boil for one and a half hours. Dye with 1-1/4 lb. Alizarine Blue D N W, 3-3/4 lb. Alizarine Yellow and 5 oz. Alizarine Brown, at the boil for two hours.

Bronze Green.—Make a dye-bath with 2 lb. Cyanole extra, 2 lb. Tropeoline O, 1 lb. Archil Substitute N and 10 lb. bisulphate of soda, working at the boil to shade.

Green.—A very fine shade of green is dyed as follows: Mordant with 3 lb. bichromate of potash and 2-1/2 lb. tartar. Dye with 4 lb. Alizarine Blue D N W, 1-1/2 lb. Patent Blue A and 2-3/4 lb. Alizarine Yellow.

Blue Green.—Mordant as in the last recipe. Dye with 6 lb. Alizarine Blue D N W, 1-1/2 lb. Patent Blue A, and 1-1/4 lb. Alizarine Yellow G G W.

Bright Pale Sage Green.—Mordant with 3 lb. bichromate of potash and 2 lb. sulphuric acid. Dye with 5 lb. Alizarine Yellow G G W, (p. 132) 3/4 lb. Alizarine Brown and 1-1/4 lb. Alizarine Blue D N W.

Deep Sage Green.—Mordant with 3 lb. bichromate of potash and 2-1/2 lb. tartar. Dye with 4 lb. Alizarine Yellow G G W, 3-1/4 lb. Anthracene Brown and 2-1/4 lb. Alizarine Blue D N W.

Pale Sea Green.—Mordant with 2 lb. bichromate of potash and 1-1/2 lb. tartar. Dye with 1 lb. Coeruleine B.

Bottle Green.—Mordant with 3 lb. bichromate of potash and 2-1/2 lb. tartar. Dye with 20 lb. Coeruleine S W.

Slate Green.—Mordant with 2 lb. bichromate of potash and 1-1/2 lb. tartar. Dye with 3 lb. Alizarine Green S.

Invisible Green.—Mordant with 3 lb. bichromate of potash and 2-1/2 lb. tartar. Dye with 17-1/2 lb. Alizarine Green S.

Peacock Green.—Mordant with 3 lb. bichromate of potash and 2-1/2 lb. tartar. Dye with 8 lb. Alizarine Green S.

Dark Bottle Green.—Mordant with 4 lb. bichromate of potash and 3 lb. tartar. Dye with 15 lb. Anthracene Blue W G, and 1-1/2 lb. Mordant Yellow.

Invisible Green.—Mordant with 3-1/2 lb. bichromate of potash and 2-1/2 lb. tartar, working at the boil for one and a half hours. Dye with 20 lb. Alizarine Green S W, and 1 lb. acetic acid.

Sage Green.—Give a medium indigo ground to the wool in a vat, then dye for one hour at the boil in a vat containing 1/2 lb. Anthracite Black B, 2 lb. Anthracene Yellow C, 2 oz. Diamine Fast Red F, and 5 lb. acetate of ammonia; then lift, add 3 lb. fluoride of chrome, re-enter into the dye-bath and work half an hour longer at the boil; lift, wash and dry.

Peacock Green.—Give a medium indigo bottom on the vat, then dye for one hour at the boil in a dye-bath made with 1/2 lb. Anthracene Yellow C, 2 oz. Diamine Fast Red F, and 5 lb. acetic acid; then lift, add 3 lb. fluoride of chrome, work for half an hour longer at the boil, then lift, wash and dry.

Bottle Green.—Mordant by boiling in a bath of 3 lb. copperas (p. 133) and 1 lb. oxalic acid. Dye in a bath with 15 lb. Gambine R.

Light Green.—Mordant with 3 lb. copperas and 1 lb. oxalic acid. Dye with 2-1/2 lb. Gambine Y.

Medium Green.—Mordant as in the last dye with 10 lb. Gambine Y.

Deep Grass Green.—Mordant with 3 lb. bichromate of potash and 2-1/2 lb. tartar. Dye with 9 lb. Coerulein and 1-3/4 lb. Galloflavine.

Bright Grass Green.—Mordant with 4 lb. copperas and 1 lb. oxalic acid. Dye with 5 lb. Gambine Y, 1/2 lb. Yellow N, and 2 lb. bisulphate of soda.

Shades dyed with Gambine are very fast to milling and light.

Pale Sage Green.—Mordant with 3 lb. bichromate of potash and 1 lb. tartar. Dye with 1/2 lb. Milling Yellow O, 2 lb. Alizarine Black S W, and 2 lb. acetic acid.

Medium Green.—Mordant with 2-1/2 lb. bichromate of potash and 1-1/2 lb. oxalic acid. Dye with 1-1/2 lb. Diamond Yellow B, 3-1/2 lb. Brilliant Alizarine Blue G, and 1 lb. acetic acid.

Invisible Bronze Green.—Give a medium bottom on the indigo vat and then mordant with 3 lb. fluoride of chrome and 2 lb. tartar. Finally dye with 3 lb. Alizarine Bordeaux S, and 4 lb. Diamond Flavine, working at the boil for two hours.

Pale Slate Green.—Mordant with 3 lb. bichromate of potash and 2-1/2 lb. tartar, and then dye with 1 lb. Alizarine Blue D N W, Alizarine Yellow and 5 oz. Alizarine Brown.

Light Green.—Mordant in the usual way with 2-1/2 lb. bichromate of potash and 2 lb. tartar. Dye with 1 lb. Methylene Blue and 1 lb. fustic extract, working at the boil.

Fast Green.—Mordant with 8 lb. alum, 2 lb. bichromate of potash, 2 lb. sulphuric acid and 3/4 lb. tin salt. Dye with 20 lb. indigo (p. 134) extract and 10 oz. fustic extract, working at the boil for one and a half hours.

Bottle Green.—Mordant with 3 lb. bichromate of potash and 2-1/2 lb. tartar. Dye with 4 lb. extract of fustic, 1 lb. extract of logwood, and 2 oz. Anthracene Red. Work for one and a half hours, then add 3/4 lb. copperas, and work for half an hour longer.

Dark Green.—Mordant with 3 lb. bichromate of potash and 2-1/2 lb. tartar. Dye with 1-1/2 lb. Methylene Blue, 1-1/2 lb. extract of logwood, and 4 lb. extract of fustic, working at the boil for two hours.

Olive.—Prepare a dye-bath with 1-1/2 lb. Yellow N, 1/4 lb. Archil Substitute, 4 lb. extract of indigo, 10 lb. Glauber's salt, 2 lb. sulphuric acid, and 2 lb. alum, working at the boil to shade.

Bright Green.—Prepare a dye-bath containing 8 oz. Acid Green Extra and 10 per cent. bisulphate of soda. Enter at 130 deg. F., raise to the boil, boil for three-quarters of an hour, and rinse.

Bluish Green.—Prepare a dye-bath containing 8 oz. Fast Acid Green B N and 10 lb. bisulphate of soda. Enter at 130 deg. F., raise to the boil, boil for three-quarters of an hour, and rinse.

Bluish Green.—Prepare a dye-bath containing 8 oz. Cyanole Green 6 G and 10 lb. bisulphate of soda. Enter at 130 deg. F., raise to the boil, boil for three-quarters of an hour, and rinse.

Turquoise Green.—Prepare a dye-bath containing 8 oz. Cyanole Green B and 10 lb. bisulphate of soda. Enter at 130 deg. F., raise to the boil, boil for three-quarters of an hour, and rinse.

Slate Green.—Mordant the wool by boiling for one and a half (p. 135) hours in a bath containing 3 lb. bichromate of potash, 1-1/4 lb. Copper sulphate and 2-1/4 lb. tartar; then rinse well, and dye in a bath containing 2-1/2 lb. Logwood Extract (dry), 1-1/4 lb. Fustic Extract (dry), and 3 lb. Sumac. Enter the goods in a warm bath, work for half an hour, then raise to the boil and work for three-quarters of an hour; lift, and sadden by adding 6 oz. Copperas. After re-entering the goods, work to shade.

Olive.—Boil two hours in a bath consisting of 1-1/2 lb. tin salt, 2-1/2 lb. bichromate of potash, 10 lb. alum and 2-1/2 lb. sulphuric acid. Then enter in a boiling dye-bath containing 1-1/2 lb. alum, 4 lb. fustic extract and 3-1/2 lb. indigo extract.

Fulling Fast Olive.—For one hour upon a bath containing 50 lb. Fustic, 5 lb. Bluestone, 2 lb. Tartar, 4 lb. Sumac, 1 lb. Copperas; lift and wash.

Fast Bright Olive.—Boil for one hour upon a bath of 50 lb. Fustic, 3 lb. Bluestone, 2 lb. tartar, 1 lb. copperas, 2 oz. indigo extract.

Yellow Olive.—Prepare a bath containing 10 lb. Glauber's salt, 1-1/2 lb. Anthracene Yellow B N, 2 lb. extract of indigo, 3 oz. Orange E N Z, 4 lb. sulphuric acid. Enter yarn at 160 deg. F., give three turns, raise the temperature slowly to the boil, turn to shade; lift, and wash.

Olive Green.—Mordant with 2 lb. potash bichromate, 1-1/2 lb. sulphate of copper, 1/2 lb. sulphuric acid. Boil for an hour and a half. Dye in a bath with 8 lb. Fustic extract, 5 lb. Sumac, 5 lb. Logwood, at the boil for an hour and a half.

Olive Bronze.—Make the dye-bath with 10 oz. Fast Yellow S, 5 lb. Indigo extract, 5 oz. Orange E N Z, 4 lb. sulphuric acid, 10 lb. Glauber's salt. Enter yarn at 140 deg. F., work for a few minutes, then bring slowly to the boil and work to shade.

Emerald Green.—Prepare the dye-bath with 1 lb. Acid Green B N, (p. 136) 2 oz. Naphthol Yellow S, 10 lb. Glauber's salt, 2 lb. sulphuric acid. Enter cold, then raise to the boil and work for a quarter of an hour; wash and dry.

Invisible Green.—First mordant the wool in a bath containing 3 lb. bichromate of potash, 1-1/2 lb. copper sulphate, 1 lb. sulphuric acid. Work at the boil for one and a half hours, then dye in a fresh bath containing 2 lb. Milling Yellow O, 2 lb. Logwood extract, 20 lb. Glauber's salt. Work at the boil for one and a half hours, then lift, wash and dry.

Sea Green.—Prepare a dye-bath with 5 lb. Glauber's salt, 2 lb. sulphuric acid, 2 lb. indigo extract, 1/2 per cent. Acid Green blue shade. Dye as usual.

Cyprus Green B, and Cyprus Blue B, belong to a new group of dyes that owe their value in wool dyeing to the fact that the dyeings after being treated with copper sulphate become very fast to light and washing. Three per cent. of each gives very full shades of bluish green or dark blue. The dyeing is done with Glauber's salt and acetic acid when reddish shades are got; these in a bath of copper sulphate turn green or blue.

BLUE SHADES ON WOOL.

There are a very large number of blue artificial dyes of every class, but only a few natural ones, indigo and logwood, and with these every imaginable tint and shade of blue from the palest sky tints to the darkest navy blue or blue black can be produced.

While some of the blue colouring matters possess no great powers of resistance to light, air, washing, etc., the great majority are remarkable for their fastness to those destructive agencies.

There are but two natural dye-stuffs, indigo and logwood, from which blue tints can be dyed. With the former, a great variety of shades can be dyed of a satisfactory character as regards fastness; with the (p. 137) latter, only dark blues can be dyed, these are fairly fast to milling, but only moderately so to light.

The artificial blues derived from coal tar are very numerous, and representatives of all classes, direct, basic, acid and mordant of dye-stuffs may be found among them. The direct blue dyes do not work very well on wool. They are apt to dye very red, and somewhat dull shades, which are, however, fairly fast to washing and light. The basic blue dyes are fairly numerous, and may be used to dye from pale sky to deep navy tints. They are apt to work somewhat unevenly on to wool, owing to their great affinity for the fibre. They give shades possessing some degree of resistance to light, but which are not very fast to washing and milling, although, in this respect, there are very great differences among them. The acid dyeing blues are fairly numerous, but they dye a great variety of tints, usually fairly fast to washing, milling and light. The mordant blues are pretty numerous and of great value for dyeing wool, as they give shades which are remarkable for their fastness to light, acids and milling, hence they are most extensively used, especially for dyeing fabrics that are subject to very hard wear.

Indigo Dyeing.—It will be most convenient to begin the description of the methods of dyeing blues by showing how, and in what manner, indigo is applied in wool dyeing.

The dyeing of indigo on wool is effected in two ways, either in the usual way with acid baths, as with acid scarlets, when the so-called indigo extract is used, or in vats, when indigo itself forms the dye-stuff.

Indigo is, as all dyers know, or should know, a natural dye-stuff, prepared from the leaves and twigs of the indigo plant by a species of fermentation which produces the indigo in a soluble form from the indigo substance in the plant, followed by oxidation which results in the separation of the indigo from this solution.

It comes into this country in the form of lumps, which have a dark (p. 138) blue to bronze blue colour. The dye-stuff is insoluble in water, cold alcohol, alkalies or weak acids. When heated with strong and fuming sulphuric acid it dissolves, forming a blue liquor from which the colouring matter may be obtained on addition of soda in the form of a paste, which is used in wool and silk dyeing under the name of indigo extract. But dissolving in sulphuric acid materially affects the properties of indigo as a dye-stuff, as will be seen later on.

By the action of reducing agents the insoluble blue indigo is converted into a soluble white indigo. This body is rather unstable, and on exposure to the air it rapidly becomes oxidised and converted back again into the blue indigo. Upon this principle is based the application of indigo in dyeing by means of the vat.

Various methods may be adopted to cause the indigo to become dissolved. These may be divided into two groups: (1) Fermentation vats, in which the action of reducing agents is brought about through the influences of the fermentation of organic bodies, such as woad, bran, treacle, etc; (2) Chemical vats in which the reducing effect is brought about by the reaction of various agents on one another.

Of such vats the copperas and lime and the hydrosulphite vats are examples. The fermentation vats, when in good order, work well and give good results, but they are most difficult to prepare or set. The chemical vats are the easiest to work, and (especially the hydrosulphite vats) are coming to the fore, and are gradually driving out the fermentation vats.

The actual method of dyeing with the indigo vat is the same with all methods of preparation. The material to be dyed is well wetted or wrung out in water. It is then dipped into the vat, handled a few minutes to ensure its thorough impregnation, then lifted out, the surplus liquor wrung out, and the material exposed to the air, (p. 139) when the indigo white on it soon absorbs oxygen and turns into blue indigo.

With these few preliminary remarks the methods of setting the various indigo vats will now be described in detail.

Woad Indigo Vats.—This is one of the most difficult of the various methods of setting vats. There are so many opportunities for it to go wrong, and to be able to set a woad vat successfully will go far to make a man a successful indigo dyer. No two woad vat dyers use exactly the same recipe in setting a woad vat, and each considers he has a secret art by means of which he ensures the successful working of this vat, and this he jealously guards. All these differences in the manner of setting the vat are brought about not by any radical differences in the materials used, but by some unnoticed differences in other surroundings; differences in the mean temperature of the water used, in the general conditions of the atmosphere of the indigo shed and in other similar circumstances, all of which have a material influence on the development of the vat, but which are, in the majority of cases, overlooked by the indigo dyer, the result being that a method of working which is successful in one place would not be so in another. The fermentation processes depend upon the reducing action brought about by certain organisms of the nature of the yeast plant which grow and develop in such vats.

To ensure the proper growth and development of these organisms every condition must be perfect, correct temperature, proper proportions of food for them to live on, and a certain degree of alkalinity or acidity of the vat, and these points are most difficult to regulate as they will vary very much from time to time.

A successful vat maker is one who closely observes his vats, and the way in which they are working, and who, as the result of such (p. 140) observations, is able to tell in what way his vats are deficient, so that he may know how to supply that deficiency.

The following method of setting a woad vat may be adopted. It is calculated for 100 gallons of liquor. The vat is filled with hot water, and 80 lb. of woad are allowed to steep overnight in it, having first been well stirred into the water, so as to ensure that every part is wetted out. The next morning there is added 8 lb. madder, 12 lb. bran, 5 lb. quick-lime (previously slaked with water), and 2-1/2 lb. soda. These are thoroughly stirred together, then from 5 to 7-1/2 lb. indigo is stirred in. The indigo should have been previously ground into a fine paste with water. The temperature of the vat should now be maintained at from 115 deg. to 125 deg. F. for two to three days, at the end of which time it ought to be in a state of quiet working. Should it be found that the fermentation is going on too rapidly, a little lime may be thrown in, which will retard it. On the other hand, if it should not be going on with sufficient energy, this may be remedied by adding a little bran, or better, a little treacle.

When in perfect condition the vat should have a slight smell of ammonia. If this is not noticed it indicates that the vat is deficient in alkalinity, and a little more lime should be added. Soda may be used in the place of lime, but it is so much more energetic in character that any additions of it have to be made with great care, or the vat will become too alkaline in character, and the fermentation will go on too rapidly, the ammoniacal odour is lost, and a peculiar putrid smell takes its place. As soon as this is noticed, lime ought to be added to retard the fermentation and to develop the ammoniacal smell. The colour of a good well-set vat is olive brown.

When all the indigo is dissolved and the colour of the vat is a (p. 141) clear olive yellow to brown the vat is then ready for dyeing, and may be used for a long time, until, in fact, the deposit gets too large and the wool becomes dirtied. But it must not be continually worked, or it will give bad shades and loose colours. When in a bad condition it will usually turn of a dark brown colour, and give dull greenish shades. To remedy this there should be added some bran, treacle, and a little madder, as well as indigo, and the vat should be left for a day, at a temperature of 130 deg. F., to get up to full strength again. Every night when in work indigo ought to be added to the vat in proportion to that consumed during the day, with bran and lime, the latter in not too great amount, just sufficient to keep it of the necessary alkalinity.

Hydrosulphite Vat.—This is one of the best vats to use in dyeing with indigo on wool, or, indeed, on any textile fabric. It is easy to prepare and cleanly to work. While depending solely on chemical action for its preparation and use, it is freer from those peculiar defects to which organic vats, like the woad vats, are liable.

There is a further advantage about this vat, it is not necessary to prepare each individual vat separately, but a strong mother liquor or concentrated indigo solution may be prepared, and this only requires letting down with water to produce a vat of any required strength.

In the preparation of this vat, which was devised by Schutzenberger and Lalande, bisulphite of soda and zinc dust are used with either quick-lime or caustic soda. The bisulphite of soda is allowed to act on the zinc as will be detailed when an acid solution of sodium hydrosulphite NaHSO_{2}, more strictly hydrogen sodium hydrosulphite, is obtained. The acid solution of hydrosulphite has the property of rapidly reducing and dissolving indigo, and this solution may be used in dyeing. To prepare the hydrosulphite a vessel which is fitted (p. 142) with an agitator and can be closed is filled with zinc, either in the form of dust, foils, or granules. Then bisulphite of soda of 50 deg. to 60 deg. Tw. strength is poured over the zinc in sufficient quantity to cover it. All access of air should be avoided as much as possible, as it leads to oxidation. In the case of using zinc powder the action is often so rapid as to lead to heating, which also should be avoided. The operation takes from an hour to two hours, when the liquor may be drawn off. It must be used immediately to dissolve the indigo; or otherwise, as it is a very unstable body, it is liable to decompose and become oxidised, when it loses its solvent properties. If more hydrosulphite is required, fresh bisulphite may be poured over the zinc which is left unused in the vessel; if no more is wanted the zinc which is left should be well rinsed in water and the vessel filled with water, so as to prevent any oxidation of the zinc, and so keep it ready for use when required. The liquor thus made will usually have a specific gravity of 62 deg. Tw. The zinc which is used up in the preparation of the liquor is replaced by fresh zinc from time to time.

The liquor so obtained is, as stated above, rather unstable, and contains acid sodium hydrosulphite. By mixing with milk of lime, the acidity is neutralised, zinc oxide and calcium sulphite are thrown down, and a solution of neutral sodium hydrosulphite is obtained which is more stable and can be kept longer without decomposition. To prepare this, take 10 gallons of the acid liquor, as prepared in the manner described above, and mix it with 48 lb. of milk of lime, which is made from 2 lb. good quick-lime. Stir well together, allow all sediment to settle, or better, filter-press the mass. A liquor of 36 deg. Tw. strength will usually be obtained. Do not let it stand too long before use, make it alkaline by adding a little lime.

To make the mother or stock indigo, the following method of (p. 143) procedure may be adopted. Indigo, say 10 lb., is ground into as fine a paste as possible with 13 lb. milk of lime, of such a strength that 1 gallon shall contain 30 oz. quick-lime. To this is then added so much of either the acid or the neutral sodium hydrosulphite as can be made from 90 lb. of bisulphite of soda, the mixture being kept at 150 deg. F., until a comparatively clear, greenish yellow solution is obtained, this will contain about 1 lb. of indigo per gallon.

This mother liquor may be used in setting the vat as follows. The vat is filled with water which is heated to 120 deg. F., about 200 gallons being used. To this is then added 1 gallon of either hydrosulphite or bisulphite of soda to destroy the free oxygen it contains, and prevent it from oxidising the indigo solution, which is next added. The quantity of the latter is solely regulated by the depth of shade it is desired to dye, and as soon as the requisite quantity has been added the dyeing may be proceeded with at once, and the first portion of goods put through will soon show the dyer whether too much or too little of the mother indigo has been added.

Continued use and the consequent agitation of the vat thereby generated causes it to become oxidised, and the vat acquires a greenish colour, and does not give fast colours. When this is noticed the use of the vat is stopped; it is heated to about 160 deg. F., and a little lime and hydrosulphite added, when all the oxidised indigo in the vat will speedily be reduced, and the vat put into a workable condition again. By use this vat tends to become alkaline, and consequently will spoil the wool, making it harsh and brittle. This is remedied by adding a little hydrochloric acid.

Holliday's Patent Indigo Vat.—Messrs. Read Holliday & Sons have patented an improved method of making an indigo solution and the method of using it. They supply the indigo in the form of solution in two strengths, ordinary and concentrated. Both are used in the same way, only of the latter less, about one-fourth to one-third, is (p. 144) required than of the former. For those who would wish to buy their indigo ready prepared for use these are very convenient forms.

The best way of working the vat for wool is the following: 40 gallons of water heated to about 50 deg. C., add 1/4 lb. of a mixture of 1-1/4 gallons bisulphite of soda, 52 deg. Tw., and 1 lb. zinc dust, and, say, 1/2 gallon to 2 gallons, of the patent indigo solution, according to the depth of shade required. The boiled out wool is worked below the surface of the liquor for about three minutes, then taken out, and the excess of liquor squeezed back into the vat, the whole operation is repeated until the shade is arrived at. After dyeing, rinse in an acid bath of 1 deg. to 2 deg. Tw.

The advantages of this new vat are that brighter shades are obtained and the darker shades with fewer dips, while the goods are dyed cleaner and the shades are more quickly obtained, and, we think, somewhat faster than by the other process.

There is also the advantage that no lime or other alkali is used with this new indigo vat. The wool should be boiled out before dipping, if the best results and even shades are desired.

Potash-Indigo Vat.—This is also a fermentation vat, and is set in the following manner: 5 lb. of madder and 4 lb. of bran are mixed with 50 gallons of water and heated for from three to four hours, until a temperature of from 180 deg. to 212 deg. F. is attained. Then 15 lb. of carbonate of potash are added and the liquor is allowed to cool down to about 120 deg. F. Next 10 lb., more or less according to shade required, of finely ground indigo is added, and the whole is left for from forty-eight to sixty hours to ferment, being stirred up at intervals of twelve hours. This vat ferments in much the same way as the woad vat, and presents the same general appearances. It is not so liable to get out of order as the woad vat, and in consequence is (p. 145) much more easily managed. It does not, however, give such bright shades as either of the vats previously described, but it dyes a little quicker, and deeper shades can be produced. It is the best vat to use where indigo dyeing is carried on at irregular intervals, also for dyeing dark shades of navy blue and for giving an indigo bottom for dark blues, browns and greens. Such shades stand milling and alkalies very well.

Soda-Indigo Vat.—The soda-indigo vat is set in the following manner: 100 lb. bran is boiled with 200 gallons of water for three hours, then the liquor is allowed to cool from 100 deg. to 120 deg. F. Then 20 lb. of soda crystals, 5 lb. slaked lime, and 10 to 15 lb. ground indigo are added, the mixture being left for two or three days to ferment, and stirred up at intervals.

Sometimes a little more soda or a little lime is added, as may be judged from the appearance of the vat, these appearances being practically the same as those met with in the woad vat, which have already been described in detail.

The soda vat closely resembles the potash vat, but is cheaper to produce. It keeps its dyeing power longer, but is somewhat more liable to get out of order. It is like the potash vat, easier to manage than the woad vat, as with all the woad vats it is necessary after working them for a day to replenish them with a little indigo, soda, or potash, as the case may be, and a little bran.

Cleaner vats are obtained if treacle be substituted for the bran, but the latter ferments better, and gives better results in working.

Urine-Indigo Vat.—This vat has almost, if not quite, gone out of use, being a rather unpleasant vat to work with, with few advantages over other vats. One advantage it possesses over the woad and potash vats is that it is the best for working on a small scale, but the modern zinc reduction vats run it very close in this respect. The vat is (p. 146) made as follows: To 50 gallons of stale urine 4 lb. of common salt are added, and the mixture heated to from 120 deg. F. to 140 deg. F. Then 1 lb. madder and 1 lb. ground indigo are added, and the mass is well stirred. Then the mixture is allowed to stand until the indigo is completely reduced, when the vat is ready for dyeing.

Indigo-Indophenol Vat.—Messrs. Durand, Huguenin & Co. have introduced the use of Indophenol along with indigo in wool dyeing. Indophenol can be reduced in the same way as indigo, and fibres dipped in this reduced product on exposure to air turn blue in the same way as if dipped in an indigo vat.

By itself indophenol has not met with much favour from dyers for a variety of reasons, but it has been found that, mixed with indigo, it can be used in dyeing with some advantage on the score of cheapness. The newly mixed vat is made in the following manner:—

In a convenient vessel 26 gallons of water, 15 lb. zinc dust, ground into a paste with 6 gallons of water, and 7 gallons bisulphite of soda of 55 deg. Tw. strong are mixed. Then 8 pints caustic soda lye of 72 deg. Tw., and 16 pints liquor ammonia are added, and the whole mass is well stirred up; 22 lb. good indigo of about 70 per cent. indigotine and 7-1/4 lb. Indophenol are thoroughly ground into a paste with 7 gallons of water and 2 pints caustic soda lye of 72 deg. Tw. The paste is added to the previous mixture, and, after being well stirred in, sufficient water is added to make the total volume of liquor up to 100 gallons. The mass is stirred up from time to time during a period of from thirty-six to forty-eight hours, by which time, as a rule, the indigo and Indophenol will have been completely reduced, and the vat have acquired a canary-yellow colour; if it has not, add a little more zinc dust and bisulphite of soda. It is ready for use when it has a good yellow colour.

This forms what may be called a "mother," or stock vat, from which (p. 147) the dyeing vat is made in the following manner: Take a sufficient quantity of water to make the dyeing vat, add some hydrosulphite of soda (see below) to destroy any oxidising action the vat liquor may have, then add sufficient of the stock vat to give the required shade, this point is one which must be determined by experience. The vat is now quite ready for use, and the wool is entered and treated in the usual manner.

After dyeing each lot of wool it is advisable to add some of the stock vat to replace the indigo abstracted by the goods. When a number of dyeings have been done, it is possible that the vat may become charged with oxidised indigo and lose its clean, yellow colour. It may be restored to its former conditions by adding some hydrosulphite of soda. Of course, after considerable use this, like all other indigo vats, becomes too highly charged with sediment, etc., to give excellent results, in which case the only thing that can be done is to throw the old vat away and start a new one.

The hydrosulphite of soda referred to above is made in the following way: 4-1/2 lb. zinc dust are ground into a paste with 5-1/2 gallons of water and then mixed with 4 gallons bisulphite of soda at 55 deg. Tw., stirring well so as to keep the temperature down. Then add 3 pints caustic soda lye of 72 deg. Tw., and 3-1/2 pints liquor ammonia. Finally, add sufficient water to make 13 gallons. After standing for two or three days the preparation is ready for use. It should be alkaline in property; if not, add a little ammonia to make it so. This vat gives very good bright shades, from sky blue to dark navy, which are equally as fast as pure indigo shades.

Sometimes woollen goods dyed with indigo rub badly. The causes of this defect vary from time to time, and in many instances are often obscure in their origin. All goods intended for indigo dyeing, and more especially when shades fast to rubbing are desired, should be (p. 148) thoroughly cleansed, and before passing into the indigo vat should be thoroughly freed from any soap which may have been used in the boiling out. Then, after dyeing, they ought to be well rinsed in water and passed through a sour made with sulphuric acid (2 lb. in 10 gallons), and then washed again. Vats highly charged with sedimentary matter, or with zinc or lime, are often the cause of loose shades. The remedy is obvious, viz., the discarding of such vats and the preparation of new ones, in fact old vats are perhaps more fruitful sources of loose shades than any other cause. Soft water suits indigo dyeing better than hard water, and is to be preferred.

It is not advisable to attempt to get full or deep shades of indigo at one dip, for such would necessitate the use of strong baths. Dyeings produced in this way are liable to rub badly, because the indigo lies mostly on the surface, to which it is more or less mechanically attached. Light shades of indigo are fast to rubbing, and by repeated dippings in a light vat or a medium shade vat deep shades of fair fastness to rubbing can be got.

As repeatedly stated, no indigo vat can be worked continuously with good results; the continual agitation induced by the passage of the yarns or cloths into the liquor brings the liquor into contact with the air, and oxidation sets in, resulting in the indigo being thrown out of the liquor in its original form. When this happens the vat loses its original clear yellow or yellowish-brown colour and becomes greenish, a sure sign that the vat is getting out of condition to give good results. The remedy has been pointed out in dealing with each kind of vat, and consists essentially in adding to the vat more of the active reducing agent and allowing the vat to rest a while.

The dye-vats may be either round tubs or square wooden tanks; for yarn in hanks, when cloths or warps are being dyed, these may be fitted (p. 149) with winces and guide rollers so as to draw materials through the liquor.

The hawking machine shown in figure 22 is also very good for indigo cloth dyeing, and is largely used for this purpose.



Figure 23 also shows an excellent machine for indigo dyeing on cloth. In this the vat has a frame carrying guide rollers, round which the cloth passes, so that it travels several times through the vat liquor in its passage from one end of the vat to the other, the amount of liquor in the vat being so arranged that the cloth is entirely immersed the whole time. After going through the liquor the cloth passes between a pair of squeezing rollers, in order to have any surplus liquor taken out, then it traverses the space between sets of guide rollers arranged over the vat, during which time the indigo becomes oxidised and the blue develops, while finally it is (p. 150) plaited down on a table. The illustration clearly shows the working of the machine.

Dyeing Wool with Indigo Extract.—Sulphonated indigo, prepared by dissolving indigo in sulphuric acid, is sold under the name of "indigo extract," or "indigo carmine," in two forms—paste (containing, perhaps, 25 to 30 per cent. actual colour) and powder. Both forms are freely soluble in water, although some makes are more so than others. This quality of solubility is dependent upon the proportion of sulphuric acid which may have been used in the preparation of the extract. When this is small, what is termed indigo monosulphonic acid only is formed, which is but slightly soluble in water, and gives red shades. If a larger proportion of acid be used, then the indigo disulphonic acid is formed, which is fairly easily soluble in water, and gives bluer shades than the former.

As all forms of indigo extract are regular articles of commerce, details for their preparation will not be given here. It will suffice to say that indigo is heated with strong sulphuric acid until test samples show that the indigo has been completely dissolved, and it is then diluted with water and filtered. Sometimes it is sold in this condition under the term "chemic," but if this be used in dyeing wool it gives rather unsatisfactory results. When "sour extract" is required, the liquor filtered out is next treated with salt until all the colour has been precipitated out, when it is filtered off, drained, pressed and sold. Should "neutral" or "sweet" extract be required, then the acid liquor is neutralised with soda, and the product is salted out as before, drained and pressed to a suitable consistence. It is then sold as "indigo extract," or dried, at 150 deg. F., to a powder, which is known as "indigo carmine".

All forms of indigo extract are dyed on wool from baths of (p. 151) Glauber's salt and sulphuric acid, and therefore they can be classed with the acid-dyeing coal-tar colours. Indigo extract is notable for its level dyeing and penetrative properties, but it is not fast to light or milling.

Messrs. Read Holliday & Sons have a powder form of indigo extract which will be found very useful and to give better shades than the usual run of paste extract, while it only takes about one-fifth the quantity to give a similar shade. Working at the boil should be avoided with indigo extract, as tending to make the shades greenish in tone; from 170 deg. to 180 deg. F. will usually be found hot enough to dye good shades.

Indigo extract is not much used by itself in dyeing blues on wool, but it is extensively employed along with other dye-stuffs to produce an immense variety of shades—drabs, greens, fawns, greys, lilacs, etc., of which some examples will be given later on.

Indigo Blue.—Prepare a bath with 10 lb. indigo extract, 5 lb. sulphuric acid, and 10 lb. Glauber's salt. Work just under the boil to shade.

Sky Blue.—The dye-bath contains 1 lb. indigo extract, 2 lb. sulphuric acid, and 10 lb. Glauber's salt. Work at about 160 deg. F. to shade.

Dyeing Wool Blue with Logwood.—This method of dyeing blue on wool has lost much of its importance since the introduction of the artificial dyes, but it is still employed when a blue fast to milling is wanted. Logwood gives dark navy blue shades. The process is as follows: The wool is first mordanted by boiling for one and a half hours in a bath of 3 lb. bichromate of potash and 2-1/2 lb. of tartar. The operation must be so carried out that the non-oxidising green chrome mordant is developed on the fibre, and therefore the boiling must be thorough. In place of tartar, argols and oxalic acid are frequently used, while lactic acid or lignorosine might be employed. The dyeing is done (p. 152) in a bath of 20 to 25 lb. logwood, or 5 to 8 lb. logwood extract; the bath is started cold, heated slowly to the boil, and kept at that heat for one to one and a half hours. Between the mordanting and dyeing the wool should be well rinsed.

DYEING BLUE WITH COAL-TAR DYES.

The blue dyes derived from coal tar are very numerous, direct, basic, acid and mordant blues being known. The direct and basic dyes are very little used, but the acid and mordant dyes are extensively employed, as is indicated in the following recipes.

Dyeing with Direct Dyes. Pale Blue.—Prepare a dye-bath with 1/2 lb. Sulphon Cyanine and 10 lb. Glauber's salt. Enter the goods, and work at the boil for one hour, then lift, wash and dry.

Black Blue.—Prepare a dye-bath with 3 lb. Sulphon Cyanine, 5 lb. Glauber's salt, and 5 lb. acetate of ammonia; work at the boil for one hour. Sulphon cyanine works well with other dye-stuffs, and gives shades which are fast to milling.

Dyeing with Acid Dyes. Bright Blue.—Prepare a bath with 2 lb. borax and 1 lb. Alkali Blue B. Enter the wool at about 170 deg. F., then heat to the boil, and work for half an hour; then lift, rinse lightly, and pass into a weak sour bath, with sulphuric acid to raise to the colour.

Soda may be used in place of borax, but the latter salt maintains the softness of the wool fibre better.

By using various brands of Alkali Blue (3 R to 7 B), various shades of blue from a reddish with the 3 R to a pure blue with the 6 B and 7 B brands may be dyed. The Alkali Blues are fairly fast to light.

Dark Blue.—Prepare a dye-bath with 2 lb. Serge Blue, 10 lb. Glauber's salt, and 2 lb. sulphuric acid, working at the boil (p. 153) for one hour. This is a very common way of dyeing blues on serges, cashmeres and worsted goods. In place of serge blue, what are known as Blackley blues, or Dewsbury blues, may be employed. These have a similar composition, but vary a little in the tint of blue they give.

Navy Blue.—Prepare a dye-bath with 2 lb. Induline A, 10 lb. Glauber's salt, and 2 lb. sulphuric acid, working at the boil for one hour.

The Indulines are very useful colouring matters for dyeing navy or dark blues on wool. They have the defect of being liable to give uneven shades. This may be remedied by omitting the acid when first making up the bath, entering the wool, working for half an hour to thoroughly impregnate the material with the dye-liquor, then adding the acid, and continuing the working for another half-hour. Or the wool may be treated to a weak chlorine bath before it is dyed, by first passing it through a weak hydrochloric acid bath and then through a bath of bleaching powder. By using acetic acid in place of sulphuric acid more even shades are obtained.

Blue.—Prepare a dye-bath with 1 lb. Acid Blue 1 V, 9 oz. Acid Violet 1 V, 10 lb. Glauber's salt and 2 lb. sulphuric acid, working at the boil for one hour.

Blue Black.—For this the dye-bath is made with 8 lb. Acid Blue 1 V, 10 lb. Glauber's salt, and 2 lb. sulphuric acid, working at the boil for one hour.

Deep Navy Blue.—A very good shade is dyed with 5 lb. Acid Blue 1 V, 3 lb. Acid violet 1 V, 10 lb. Glauber's salt, and 2 lb. sulphuric acid, working at the boil for one hour.