1902 Encyclopedia > Calico Printing

Calico Printing




CALICO-PRINTING is the process of imprinting on textile fabrics patterns of one or more colours on a white or coloured ground. Though, as the name implies, the art is directed primarily, as it is by far most extensively, to calico or cotton textures, the same methods of ornarneDta-tion are also employed for certain woollen, linen, and silk fabrics, and the process of printing is also applied to unwoven yarns, notably in the case of worsted yarns intended for use in the weaving of tapestry carpets. But as certain of the processes employed for printing cotton agree essentially with those used for woollen and silk fabrics, it will be unnecessary here to refer specially to any other than the methods employed in the printing of calico proper.

There is a curious passage in Pliny’s Natural History (xxxv. 42), from which it is evident that calico-printing in his time (the 1st century) was understood and practised in Egypt, The following is a translation of this passage:—

"There exists in Egypt a wonderful method of dyeing. The white cloth is stained in various places, not with dye--stuffs, but with substances which have the property of absorbing (fixing) colours. These applications are not visible upon the cloth; but when the pieces are dipt into a hot caldron containing the dye, they are drawn out an instant after dyed. The remarkable circumstance is, that though there be only one dye in the vat, yet different colours appear on the cloth; nor can the colours, be after-wards removed. A vat which would of itself only confuse. the colours on cloth previously dyed, in this way imparts several colours from a single dye-stuff, painting as it boils." It is evident enough that the substances employed to stain the cloth, as Pliny expresses it, were different mordants, which served to fix the dye upon the cloth. Thus if we suppose certain parts of a piece of cotton cloth to be impregnated with alumina, and the cloth afterwards dyed with madder, after the clearing, those parts only impregnated with the mordant would retain their red colour, while the remaining parts will continue white.

The genesral opinion is, that this ingenious art originated in India, and from that country made its way into Egypt. Whether this notion be well or ill founded, it is certain that calico-printing was known and executed by the Indians at a very early period. Their colours, were beautiful and fast, and the varieties of pattern and the number of colours which they knew how to fix on different parts of the clo,th gave to their printed calicoes a beauty and a value of no ordinary kind; but their processes are so tedious and so clumsy that they could be put in practice only where labour was exceedingly cheap.

It was not till towards the close of the 17th century that calico-printing was introduced from India into Europe, having probably been practised first in Holland, to which country a knowledge of the art was carried by the Dutch East India Company. Evidence exists which shows that calico-printing was commenced in the neighbourhood of London so early as the year 1676, and there the art con-tinued long to be pyactised. In 1738 it extended to Scotland, and took firm root in the country around Glasgow, but it was not till 1764 that it was introduced to what is now its chief centre, Lancashire. The extent of the industry in Great Britain at the present day is probably unequalled by the combined production of all other nations of the world. The other European countries where the art is prosecuted to any considerable extent are France, Switzerland, and Germany, to the last of which the annexation of the Rhine Provinces, consequent on the war of 1870-1, has added a famous centre of the industry. The art is also extensively cultivated in the United States, while Oriental -communities still continue to prosecute it in their own pe-culiar fashions.

In Europe the art has been in a great measure created anew. By the application of machinery, and by the light thrown on the processes by the progress of chemistry, the tedious methods of the Indians have been wonderfully simplified; and the processes are remarkable for the rapidity-with which they are now executed, and for the beauty, fastness, and variety of the colours which are applied on the surface of cotton. So great have been these improve-ments, that at the present time in Manchester a piece (25 yds.) of calico can be printed in the short period of one minute; and the quantity of calicoes printed in Great Britain in one year cannot measure less than three quarters of a million of miles, seeing the exports alone of printed cotton piece goods during the year 1874 amounted to, 1,003,101,107 yards, of a value of £19,602,706, an amount exceeded by 140,000,000 yards in 1872.

Grey calico is prepared for printing by an elaborate pro-cess Of BLEACHING, for the details of which the reader is referred to the article under that head, vol. iii. p. 811. The bleached cloth previous to printing is generally passed. through a shearing machine, which removes from its, surface the fine downy pile and short threads, thus prepar-ing a smooth uniform surface capable of taking a sharp distinct impression from the engraved printing-blocks or rollers. The printing processes which follow are exceedingly complex and varied, demanding for their proper- execution an extended range of chemical knowledge andl mechanical ingenuity; and as commercial success depends largely on the tasteful and harmonious colouring of patterns, no little artistic ability and discrimination is required for the efficient superintendence of such works.

There are two modes of printing,—narnely, block-printing and machine-printing. The former has been practised from time immemorial; the latter is a modern invention, and originated after the introduction of the art of printing into, Great Britain. In the case of block-printing the figure intended to be communicated to the cloth is cut out upon a block of sycamore, the parts which are to make the impression being left prominent, and the rest of the block cut away, just as practised for wood engravings. When the figure is too complicated, and the lines too fine, to admit of being cut in wood, it is made by means of small pieces of copper, which are very ingeniously driven into the block, and the interstices are filled up with felt.

By means of a modern invention several colours may be applied at once on the cloth by means of one block. The machine used for this purpose, which is called a "toby," consists of a box divided into several compartments filled. with various colours, which are in communication through tubes with bottles filled with the same colours; and by means of a gentle pressure the colouring fluid in each of' the compartments of the machine is propelled through the felted cloth which covers each compartment. The block, being pressed against the cloth, takes the colour. which is to be conveyed to the white calico by the block-printer.

By Continental printers an intricate apparatus for print-ing called the Perrotine, from the name of its inventor, is employed; but it has never been introduced to any considerable extent in England. In this machine the intended figures are engraved upon a flat copper plate of about a square yard or more in size. Upon this plate the colour to be applied is spread. The plate is then pulled backwards, the excess of colour being removed by a

doctor, then printed on the white cloth.

Printing is now almost universally accomplished by means of cylinder machines, in which the impression is given by one or a series of engraved copper cylinders; a diffirent cylinder being -required for each separate colour or shade in the pattern. The cylinders are made about 3 feet 6 inches long and 6 inches in diameter; and in establishments of any considerable extent many thousands of these are kept in stock, involving an enormous outlay of capital. There are three differetit methods in practice for engraving patterns or portions of patterns on the cylinders.

In the first, the "die and mill" process, a cylindrical steel die is engraved with the pattern, which is afterwards transferred to a "mill" or cylinder of soft steel. The pattern on the mill is in relief, and after hardening, it is by pressure impressed into the copper roller. The diameter of the mill is such that the repeats of the pattern fit with the utmost precision when transferred to the copper roller. The "die and punch" process is a modification of the fore-going, in which small patterns are impressed on the copper cylinder by means, of a punch which has the pattern in relief transferred to it from a sunk steel die. The third process by which engraved rollers are prepared is by the aid of the pentagraph, a most complex and ingenious machine, with which by the movement of a single tracer in the deep lines of an enlarged pattern cut in a zinc plate, these lines are reproduced on the original scale, traced at five different places through a coating of bituminous varnish on the surface of the cylinder. After the engraving is complete, the cylinder is placed in a bath of dilute nitric acid, by which the pattern is bitten in along the surfaces of the metal exposed by the scratching of the pentagraph points.

Calico-printing machines are arranged to print with any number of such cylinders, from one up to as many as twenty; but in practice few machines carrying more than eight cylinders are employed. The accompanying dia-gramatic section (fig. 1.) illustrates the arrangements necessary for printing one colour, and each of the separate colours on a machine is similarly mounted round the periphery of the central bowl or cylin-der a. Against this central bowl a the engraved copper cylinder b presses, and

between them the cloth to be printed and a thick cloth or blanket pass. The cylinder is supplied with the printing material by means of a furnishing roller c, which revolves in the colour-box d. The superfluous colour is removed from the cylinder by means of the

colour doctor e, a steel blade which fits closely to the surface of the roller, and removes all colour except that which fills the engraved portions. The lint doctor f similarly removes all impurities which adhere to the roller after it has communicated its impression to the cloth. Fig 2 shows the elevation of a six-colour machine by Messrs Mather and Platt of Manchester, to whose courtesy we are indebted for illustrations of the most recent and approved forms of apparatus. The essential parts of this machine consist of the central iron bowl or cylinder A, and the six radiating arms B, each of which holds in position an engraved roller colourbox, &c., as shown in diagram fig. 1. By means of screws and other fine mechanical adjustments the pitch of each roller can be arranged so that its particular colour falls on the proper place with the utmost exactitude, producing a perfect pattern. In printing, the white calico is batched at C, and the cloth D passes inwards over tension rails, proceeding rouad the periphery of the bowl A, receiving from each roller B a separate colour or mordant, and issuing at D', printed and ready for the further processes to be hereafter detailed. Around the central bowl A are lapped, for the sake of elasticity, several folds of cloth. Between the central bowl and the cloth to be printed there passes, 1st, an endless band of cloth or blanket, seen entering at E and issuing at E'; and 2d, a "grey back" or web of unbleached calico, used to keep the blanket clean, which enters at F and issues at F'.

By whatever mechanical means the printing is performed, whether by hand-block, perrotine, or cylinder machine, the effect is precisely the same, and the colours or mordants employed are in all cases alike. The substances to be printed on the surface of the calico have to be brought to a proper consistency for printing by means of thickeners, with which they are mixed up in colour pans. Although these are only mechanical agents, it is found in the practical operation of printing that particular thickeners are more suitable for certain colours or mordants than others, and the printer is guided by experience in selecting that thickening adjunct which gives the clearest impression. Among the numerous thickeners available, those most commonly employed are wheat flour and starch, potato starch, dextrin or British gum, and gum-senegal or other varieties of gum-arabic. The mordant or the colour and its appropriate thickeners are placed in a range of colour pans, in which the materials are thoroughly incorporated. A pair of these pans (one in section), as constructed by Messrs Mather and Platt, embracing the most recent and approved appliances, is shown in fig, 3. In the cut, A represents the driving pulleys, B the driving shaft, wheels, and catch-box, c wheels for giving a rotary motion to the brass stirrers d. E is the colour pan, of copper, double eased, inade to swivel on centres or pivots f1 and f2. Through f1 water and through f2 steam are supplied to the space between the outer and inner body of the pan for the purpose of boiling and cooling down the contents of the pan alternately as required. The supply of steam or of water to these pipes is regulated by the tap g. H is the framing, J stands, with the necessary appliances for turning over the pans to empty their contents, K a pipe and swivel tap for supplying water to the pans, L is the main steam pipe to f1, m the water pipe to f2and K, and it and n are taps for washing cut and for condense water respectively.

The variety of methods by which colours are produced on calicoes is almost endless, and the processes employed, both chemical and mechanical, as well as the tinctorial agents used, are also very numerous and diversified. The processes are in practical works generally classified under the heads of numerous different styles, combinations of several of which are frequently employed in the production of a single pattern. It is at once impossible and unnecessary to enter into details of these various styles here; but they all resolve themselves into a few general groups, under which heads they will be briefly treated of. In certain styles a mordant, or chemical substance, which possesses an affinity for both the cloth and the dye-stuff, is the substance printed in the cylinder machine, and the calico has to undergo a subsequent process of dyeing by which those portions of the cloth which received the mordant are alone permanently dyed. Again, the colour-box may contain all the ingredients necessary for the production of the colour, but to develop it in the fibre it is necessary to expose the printed cloth to the oxidizing influence of the atmosphere, or otherwise produce an oxidation of the dyestuff by which the colour is developed and fixed. By a third process the colour is prepared and applied direct to the cloth mixed with some agent which, under the influence of heat and moisture, either mechanically attaches or chemically precipitates the colour in the fibre. And a fourth process, which may be regarded as a modification of the third, consists of mixinor the dye with powerful mordanting substances, which, after printing, are merely dried, the mordant Volatilizing sufficiently to fix the dye, not very fast, on the cloth. There are thus these four divisions—

I. Dye colours.
II.
III. Oxidation colours,
IV.
V. Steam colours
VI.
VII. Spirit colours.
VIII.


Along with these different methods patterns are also produced and modified by means of substances applied to cloth already dyed or printed in order to remove the colour from certain portions of it which are either intended ta remain white, or to receive some other colour afterwards. These substances are known as "discharges" and examples of their action are seen in printed Turkey reds and bandannas.



Sometimes a substance is applied to cloth before it is dyed, in order to prevent the indigo, or any other colour, from being fixed on those parts to which it is applied, that they may remain white, or be, afterwards made to receive other colours. Substances possessed of this property are called "resists."



DYE COLOURS.

Under this head are included prints prepared by printing, the pattern in one or more mordants—substances which have an affinity for the fibre on the one hand and the dye-stuff on the other. The mordanted cloth is subsequently submitted to a process of dyeing, when the dye-stuff is fixed only on such parts of the cloth as have been impregnated with the mordant. By Using more than one mordant, by mixing them, or by employing the same at different degrees of strength, a variety of shades or colours is produced in the process of dyeing with one dye-stuff.



Mordants.—The principal mordants employed for dye colours are the following:—

1. Red Liquor.—The acetate of alumina mordant or "red liquor" of the calico-printer is prepared by partly decomposing alum, held in solution by impure acetate of lime, commonly called pyrolignite of lime; sulphate of lime: precipitates and acetosulphate of alumina is thus obtained. Red liquors thus prepared have a specific gravity of 1·08, and are composed as follows:—



TABLE



In the manufacture of "red liquor," sulphate of alumina is frequently substituted for alum, and acetate of lead for pyrolignite of lime.

2. Iron Liquor.—The oxides of iron are much use& as mordants, either in the state of protoxide or peroxide. The salt most employed is the impure pyrolignite of protoxide of iron, which is prepared either by decomposing green copperas with pyrolignite of lime, or by placing in, large vats pyrolignous acid and old iron, when, after a few months, the iron, which is gradually oxidized, dissolves in, the acid, and gives rise to pyrolignite of protoxide of iron. This valuable mordant is thickened with calcined farina, flour, starch, or gum, and applied on the calico. After being exposed for a few days in a moist atmosphere, it loses a part of the acid, and becomes partially peroxidized. Pyrolignite of iron of the specific gravity of 1·05 gives a black with madder and several "tannin" substances. Various shades of purple are obtained by adding different proportions of water to the mordant previously to applying it to the cloth; and various shades of chocolates are produced by rnixing this with the alumina mordant previously described, and then dyeing also with madder.

These two mordants are the principal employed for madder colours; but several others are employed for special shades. Among these may be enumerated the aluminate of soda or alkaline pink (used as a mordant when it has to act as a resist for another colour such as aniline black), and acetates of chromium, copper, tin, and other metals.





Dye Colours.—The principal dye colour is madder or some, of its derivatives, including artificial alizarin, the dyeing principle of inadder obtained synthetically frorn anthracene. Madder is the root of a plant, Rubia tinctoria, a native of Central Asia, but introduced aad extensively cultivated in south Europe, especially at Avignon in France. For the purposes of the calico-printer, madder-root is prepared by simply grinding, or in the form of flowers of madder (fleurs de garance), of garancin, of garanceux, or of alizarin. Fleurs de garance is po wdered madder deprived of its soluble constituents and redried, whereby the tinctorial strength of the preparation is increased nearly one-half. Garancin is prepared by boiling powdered madder in sulphuric acid garanceux is spent madder similarly prepared; and alizarin, the chief tinctorial principle of madder, is obtainable from garancin by the action of superheated steam. Among the chemical principles of tinctorial value yielded by madder there is, besides alizarin, an allied substance named purpurin. Alizarin of precisely similar composition and behaviour is now artificially made from anthracene, one of the products of coal-tar, and purpurin also is obtainable by the oxidation of artificial alizarin. By chemical agency the essential ingredients of madder are thus now produced in a cheaper, more convenient, and more effective form than it was formerly possible to extract them from the cultivated root. Madder extract, garancin, and alizarin dye heavier and more brilliant colours than madder, and they require less soaping or other treatment to clean the whites after dyeing. Madder extract and artificial alizarin are also used as stearn colours.

We may now briefly follow the stages in printing a madder style, taking for example a calico printed in four ‘colours' (the technical name for whatever is printed by the machine, whether mordant or dye), with a padding or blotch of weak iron liquor. In this case the mordants or colours are—



Black from strong solution of iron liquor.

Purple from weak solution of iron liquor.

Red from solution of red liquor.

White resist of soltition of citric acid (lime juice).

Purple pad or cover of weak iron liquor, which falling on the acid resist forms a soluble ferric citrate.



Drying.—The cloth after receiving these impressions passes into a drying apparatus, generally a closed chamber, highly heated, by radiation from steam-chests of cast-iron.

Through such a chamber the cloth passes up and down over numerous rollers, traversing a long distance before it emerges dry and ready for the next process. Another

Means of drying, employed in some of the best establish-ments, such as Thornliebank, is by passing the cloth round a long series of revolving steam cans or cylinders, the metallic surface of which is covered with felt. Recently a most effective system of drying has been introduced, which consists of forcino, a strong current of heated air through an enclosed chamber by the action of a fan, connected with which is an apparatus filled with pipes, through which the air Puses, while surrounding the pipes is a steam space. By this plan any temperature may be obtained, and the current of air adjusted by the speed of the fan.

Ageing.—From the drying apparatus the goods pass to the ageing room, a lofty and spacious chamber (fig. 4), where they are exposed to the combined influence of heat and steam. The pieces pass, as shown by the arrows, up and down over rollers from end to end of the room, travelling over a long space, for twenty minutes or thereby. The atmosphere is rendered rnoist by jets of steam blowing, from pipes a, a, and hot by radiation from the same and other steam pipes. A difference of tour degrees is maintained, between the dry and wet thermometers; the readings average 80º and 76º Fahr. The cloth takes up about 5 per cent. of its weight of moisture in its passage, and as it issues at the further end of the apartment, it is piled up in loose bundles, and so left for two or three days in a warm moist atmosphere. The object of the operation of ageing is to precipitate the mordants in the fibre of the cloth, they in the meantime being partly decomposed with the disengagement of abundant fumes of acetic acid. The practical development of the modern process of ageing is due to the scientific ingenuity of the late Mr Walter Crum of Thornliebank, the method previously practised having been tedious and uncertain, depending upon variable states of the weather.

Dunging.—It is next necessary to remove any superfluous uncombined mordant which may be on the cloth, and to take away the thickening agent with which the mordant was printed. These objects are accomplished by passing the goods through hot water, in which it was formerly the practice to dissolve cow’s dung, hence the name; but now some of the numerous dung substitutes are chiefly used, the principal of which are the silicate and the arseniate of soda. The first operation in dunging is to pass the pieces through the "fly dunging" apparatus,—a cast-iron trough with rollers top and bottom—by which the cloth is made to pass, in the open state, through the hot solution. This operation fixes the mordant in the fibre and prevents it from spreading to unmordanted parts of the cloth in the subsequent washing and dyeing operations to which it is subjected. Immediately after the fly-dunging the goods are washed and submitted to a second dunging, this time in a different kind of apparatus, through which they are passed in a coil or loose rope form. They are then thoroughly washed at a machine to remove the last traces of thickening matter and all uncombined ingredients.

Dyeing.—At this point the goods are ready for dyeing, the most important process in the whole series of operations. The dye-beck or vat, one form of which is shown in longitudinal and transverse section in fig. 5, consists of trough is a stream pipe b, perforated at intervals, by which the requisite heat for the dyeing operation is raised and maintained. Sloping upward from the steam pipe is a perforated diaphragm of iron or midfeather c, and mounted on a strong framework over the trough is the winch D, which by its revolutions, effected by spur wheels, keeps the cloth moving down and up continuously into and out of the trough. A peg, rail e runs along the length of the trough which keeps the pieces from becoming entangled in their course. The figure shows the course of a chain of pieces being dyed on the endless system, in which about

twenty-five pieces, are sewn together, and passed in a spiral form up and down from end to end and back again, to go over the same course continuously throughout the entire time necessary for completing the operation. Another and more common method of arranging the pieces in the dye- vat is to pass two pieces, tied together end to end, over the winch between each separate pair of pegs, in which case the pieces revolve bet1ween the same pegs throughout the operation. Whichever method is followed, the opera-tion and results are precisely the same. The required quantity of cold water is admitted into the trough, the pieces are arranged on the winch, the dye-stuff is intro-

duced, and the machinery set in motion. Steam is then turned on, and the liquid is heated gently and gradually till it reaches about 180º Fahr. The process is continued

for from an hour and a quarter to about two hours, during which time great care is taken to maintain the temperature arrived at, and to keep the pieces in constant circulation in

and out of the vat. On the completion of the operation steam is shut off, and the pieces are rinsed through cold water, after which they are carefully and repeatedly washed. Fig. 6 presents a sectional view of an apparatus devised by Messrs Mather and Platt for loose washino, after dyeing.

In this machine there are two water-boxes a, b, and three bowls c, d, e, which are mounted horizontally in relation to each other. The central large bowl d, instead of being circular, has an irregular curved outline of alternate elevations and depressions. Against this irregular-shaped bowl the two side bowls c and e are made to press, and they move back and forward, following the irregular outline, pressed by powerful springs f acting on the axes on which they are mounted. They have thus a rubbing action in addition to their motion of revolution, an arrangement which produces a kind of flapping and squeezing action analagous to band-washing.

Clearing.—At this point the dyed calicoes present a very Unpromising appearance, the mordanted portions which have absorbed the dye being dull and heavy in colour, while the whites have a sickly pink aspect. The operations of clearing, are necessary to remove all the dye-stuff which is loosely attached to the whites, and to develop and brighten the tints of dyed pattern. A variety of processes are pursued to accomplish this object, but in all the action of soap and some "chemick" or chlorine solution Plays the principal part. The soap used must be free, from all excess of alkali, and besides its detergent action it is supposed to be decomposed and give up part of its fatty acid to the lake fornied by the mordant and the dye-stuff. The processes for clearing, such calicoes as here described are as follows. After washing out of the dye-beck the goods are passed into a soaping beck, very similar in construction to the dyebeck, but surmounted with a pair of squeezing rollers instead of the winch of the dyeing apparatus. In this they are treated with a hot solution of soap; they are then washed out, squeezed, and again soaped—the second time at a higher temperature than the first. After another washing they are "chemicked" in a weak Chlorine solution, prepared by mixing chloride of lime with soda ash, with excess of soda, and from that a final washing in pure water should leave the goods clear and bright, ready for the finishing operations they receive in common with all other styles.

The reds and pinks produced by an alumina mordant with madder or artificial alizarin receive a different treatment. Mr Charles Dreyfus of Manchester, in a paper of great practical value communicated to the Society for the Promotion of Scientific Industry,1 says of these colours: "They were some time ago dried and steamed; by the steaming a further quantity of colouring matter was combined to the mordant, and the shades thus obtained were fuller than if the goods had not been steamed. Now, instead of steaming only, the goods are passed through preparations the basis of which are fatty acids or fatty or resinous compounds; they are steamed after this preparation. I can speak highly of the good results obtained with some of these preparations, both as regards shade and saving of colour. The only difficulty is to obtain a good white; this can be overcome by careful and proper treatment of the goods. For reds and pinks there is a special and extra operation, commonly called the ‘cutting.’ It consists in passing the goods soaped and well washed through diluted nitromuriate of tin; the reds and pinks seem to be destroyed, becoming of a deep orange, but the subsequent soaping brings out again the- brilliancy of the shade."

The processes above described are followed, with only modifications as to strength of mordants and the clearing operations, for the printing Of calicoes with the madder preparations,—garancin, garanceux, and alizarin. The colours produced by these substances are as brilliant as madder colours, but they do not possess such fastness. On the other band, the whites are not deeply stained in the dye-beck, and they generally require only a simple padding tbrough a weak chlorine solution, and washing to clear the whites and prepare the goods for finishing. Some garancin and alizarin shades stand soaping well, and are improved in tone by such a treatment. Artificial alizarin and madder extract are now however chiefly used as steam colours, and to such perfection has printing in that style attained that the dye-house has been abandoned altogether in certain Continental establishments. The retention of dye-colour printing may now indeed be looked on as a question of comparative expense, which is determined chiefly by the price of fuel.

Turkey Red.—The production of this beautiful colour belongs rather to the province of Dyeing than to calico-printing; but as patterns are produced on it by means of discharges, it is necessary to include a notice of it under the head of dye colours. It is obtained with madder,



FOOTNOTE (page 688)

(1) Journal of the Society, vol. i. No. 3, Dec. 1874.



garancin, and both natural and artiticial alizarin, but the pieces previously to being dyed have to undergo a long series of operations, which consist in passino, them suc-cessively in olive oil and carbonate of soda, and hang-ing them in the air between the processes. They are then passed into a weak solution of red mordant, and afterwards of gall-nuts or sumach, well washed, and dyed in madder. When this has been effected, the colours are brightened by being boiled under pressure in a solution of soap and chloride of tin. On cloth so prepared certain discharge mixtures, principally tartaric acid properly thickened, are printed, and the pieces are passed through a solution of chloride of lime which removes the red, leaving a white pattern on a red ground. If a mineral colour or mordant is printed with the discharge it is left on the cloth in place of the discharged Turkey red, and thus various shades are produced in the brilliant red ground. In bandanna printing the Turkey red calico is folded between metallic plates, which are perforated with designs, and so arranued that each figure of the design corresponds through the pile of prints so folded. The whole is then submitted to pressure, and a chlorine liquor is forced by pressure to percolate through the mass, which destroys the red colour in all those parts where the perforated plates allow the bleaching liquor to circulate.

Although madder and its various derivatives are the principal dye colours, there are various others which may be and sometimes are so treated. Of these the most important is logwood, the wood of Hoematoxylon campech-ianum, which, although chiefly used as an oxidation colour, also yields with alumina and iron mordants black and sombre slate tints, which, however, do not possess the peculiar fastness of madders. Sapanwood and peachwood are also used as dye colours, the mordant and method of dyeing being the same as for madder or garancin; the cloth, however, does not receive the same treatment after dyeing, and does not require it, because these colours are much more easily removed from the parts of the cloth which are destitute of mordant. Beautiful reds and pinks are produced by means of cochineal; but this dye-stuff is chiefly used as a steam colour and for mousselines de laine. The mordant in the case of calicoes is either alumina or oxides of tin, and the method of proceeding is similar to that already described for madder and garancin colours. Quercitron bark (Quercus tinctoria), and flavin—a prepara-tion from it, fustic, the wood of Maclura tinctoria, and Persian berries, the fruit of Rhamnus infectorius, are all used as dye colours, chiefly for the production of various shades of yellow. In the paper above quoted, Mr C. Dreyfus states that mahogany has lately been brought out as a colour-giving substance, that it gives with the tin and alumina mordants very bright and fast shades of brown, much more brilliant than those made from catechu, and that he has dyed some very good specimens with Spanish mahogany.





OXIDATION COLOURS.

Under this head is included a class of tinctorial substances which attach themselves to cotton fibre without the intervention of any mordant, but which for the development and fixation of their colour must undergo a process of oxidation after printing in the machine. The oxidation may be induced either by exposure, of the pieces to atmospheric influences, by passing them through a solution containing an oxidizing agent, or by printing with the material some chemical substance which on exposure to heat gives off oxygen. The materials principally treated in this manner are indigo, catechu, aniline black, and certain blacks obtained from logwood. The processes udopted for the printing of indigoand aniline black—the two most important styles under this head—will make the practical application of the oxidation principle clear.

Indigotin, the colouring principle of indigo, is a substance obtainable from several other plants besides the, species of Indigofera, from which it is commercially prepared. It is a body altogether insoluble in water, alcohol, ether, oils, or dilute acids or alkalies; but in presence of a variety of substances it takes up an additional equivalent of hydrogen, and thus is converted into white indigo, a colourless substance soluble in solutions of alkalies and alkaline earths. The change is thus represented.

White indigo is a most unstable compound, taking up oxygen with great facility either from the air or from certain solutions, and thus becomino, retransformed into blue indigo. Advantage is taken of these circumstances in printing indigo colours; the colour is hydrogenized and dissolved, in which condition it is applied to calico, and on exposure of the pieces so dyed to the influence of oxygen the blue colour is both developed and fixed in the fibre. The following are the principal styles in practice:—

Indiyo-blue dips.—This fine blue colour is produced in the old Copperas vat method by putting in a vat hold-ing 2000 gals. of water 60 lb of finely ground indigo, to which is gradually added 120 lb of green Copperas, or sulphate of protoxide of iron, together with 180 lb of slaked lime. Owing to the lime removing the sulphuric, acid from the salt of iron, the protoxide of that metal is liberated, and by its affinity for oxygen it decomposes the water, liberating hydrogen, which in its nascent condition reacts on the blue indigo, and thus transforms it into white indigo, which is soluble in the, excess of lime employed in the operation. A zinc vat of recent introduc-tion is now much more generally adopted than the above, its advantages being that the indigo is much more quickly converted, and by avoiding the abundant precipitate of sulphate of lime a better clms of work is produced. The zinc vat is prepared by adding to the 2000 gals. of water 20 lb of ground indigo, 30 lb of iron filings, 30 lb of finely powdered zinc, and 35 lb of lime. The powdered zinc in presence of the lime decomposes the water, giving off hydrogen, which is taken up by the indigo, which then as white indigo dissolves in the lime.

By whichever process prepared, the dye-vat being ready, a piece of calico is hooked on a wooden frame and well stretched out; it is then dipped into the vat for fifteen minutes, taken out, and left exposed to the air for five minutes. The piece of calico, which is white when it comes out of the vat, gradually becomes green and then blue, owing to the oxygen of the air oxidizing the white indigo, and transforming it into blue, which is insoluble in water and fixed on the calico. The number of successive dips that the piece undergoes varies according to the various shades of blue which the printer requires. The pieces, after having been passed into a weak solution of sulphuric acid or "sours," which fixes the indigo thoroughly, only require to be well washed and dried.

To produce the well-known style of print which con-sists in a blue ground and white design, it is necessary to print a resist, pass the pieces into a vat containing lime,

and then dye them in the above indigo vat. The prin-cipal resist used is the blue resist, a mixture of sulphate, acetate, and sometimes nitrate of copper, and the solution

is thickened with British gum, or calcined flummery, together with pipe-clay for the block, and flour for the machine printing. When the cloth on which this paste has been printed is dipped into an indicro vat, the indigo is oxidized before it reaches the surface of the cloth. After dyeing, the pieces are passed through weak sulphuric acid, not only to remove the oxide of copper, which has been precipitated, but also to fix the indigo on the calico, by liberating it entirely from its lime combination. Various other resist pastes are employed when it is desired to print other colours over the white portions, as for example, when -orange or yellow grounds are desired the mixture consists of a salt of copper to resist the blue indigo vat, with a salt of lead to produce the chromate of lead by treatment with bichromate of potash after the blue dyeing, is complete. The late J. Lightfoot of Accrington devised and patented, in 1867, a method of printing reduced indigo simultaneously with the mordants for madder, garancin, and other dye colours, by which a combination of indigo blue with other tints can be obtained of perfect clearness and brilliancy, without resorting to the complex and tedious processes involved in discharging colours, repeated printings, &c., when colours are blocked on a blue ground. The success of his process depends on the preparation of a pulp of indigotin and tin, in which he carefully avoided any excess of tin salt, so that it does not attract the alizarin in the madder beck, and in consequence leaves the indigo effects clear and unclouded.

China Blue.—This style of print is obtained by printing on the calico a mixture composed of pulverized indigo and sulphate of protoxide of iron, to which is sometimes added orpiment, and thickened with British gum. The pieces so printed are passed alternately, by means of rollers, first into a milk of lime, and then into a solution of sulphate of protoxide of iron, when there ensues one of the most in-teresting phenomena of calico-printing; for as fast as the blue indigo is reduced into white indigo, instead of being dissolved by the lime of the bath, it is retained with force through the molecular attraction of the fibre of the calico, and prevented leaving the cloth until it is fixed by the exposure of the piece to the oxygen of the atmosphere. The pieces then only require to be passed into weak sulphuric acid, washed, and dried, in order to be com-pleted. This process is not now much used.

Pencil Blue is obtained by reducing blue into white indigo, by boiling it for several hours with protochloride of tin and alkali. When the indigo is well reduced, citrate of soda and starch are added; and after the whole is carried to the boiling-point, the calico is printed with it, passed into a milk of lime, washed, and dried.

Aniline Black is a most beautiful and fast colour, pre-pared by mixing a salt of aniline with a metallic salt and an oxidizing agent, which substances on exposure gradually react on each other, and develop a rich velvety black. There is thus produced one of the most unalterable colours known, resisting soap, acids, and even chlorine to a remark-able extent. It is a colour of recent introduction, having been first printed by Mr John Lightfoot of Acerington, in 1859, and patented in 1863; but it is now in very exten-sive use, many different methods for producing it having been devised and patented. The most extensively employed system. is that patented in 1871 by Mr Lightfoot, the originator of the colour, which is thus given by Mr Dreyfus—30 pints chlorate, of ammonia, prepared either by means of tartaric acid and chlorate of potash, or by another process without tartaric acid, are thickened with 6 to 8 lb wheat starch and 6 to 8 lb best dark British gum. When this colour has been well boiled, it is allowed to get cool, and then 7 pints of a solution of the purest and most neutral aniline salt that it is possible to get are added; this solution is made with 8 lb of salt to the gallon of water, with three-quarters to one pint of sulphide of copper paste. After the mixture is printed, the pieces are lightly dried and hinag in the ageing room in a moist warm atmosphere, with the dry bulb thermometer about 80º and the wet bulb 10º lower. From Thirty hours

are required to develop the colour, the printer judging of the progress of the ageing by the tint. According to Mr William Mather an ordinary ageing machine will

effectually "age" the aniline black, if only a proper current of air is maintained of the requisite moisture and tempera-tre. This is readily accomplished by having a properly

contrived outlet to the chamber at the top, the draught of hich is controllable, and inlets for fresh air in the side at of the chamber. This mode Air Mather states is in successful

operation, and by simple mechanical contrivances may be universally adopted. When the pattern has assumed a deep bottle-green tint, the goods are removed and passed

through a solution either of bichromate of potash, of carbonate of soda, or of both mixed, and then soaped and dried.When aniline blacks are to be further printed with steam colours or dye colours, as is commonly the case, the treat-ment of the pieces after ageing is modified according to the necessities of the case.

Chrome Black is an oxidation colour produced by printing with logwood liquor and passing the goods through a bath of bichromate of potash, when the colouring principle of the logwood—haetoxylin—undergoes a special oxidation. The colours, obtained from catechu, are also fixed by oxidation, the colouring principle—catechuin—being only soluble in its unoxidized condition, and when oxidized after printing, it yields various browns and drabs, which have a very high degree of fastness.



STEAM COLOURS.

The various processes of printing included under this head are of modern introduction, but they have steadily risen in importance, till now they embrace the largest part of the art, having so largely and rapidly superseded all other styles that the process would appear to be destined to become the predominant style of the future. Indeed, to such perfection have steam colours been brought that in some Continental establishments, it appears, the dye-house has been altogether closed and steam colours only now printed. As compared with the printing of dye colours the "topical" or steam colour style is simple, direct, and expeditious, requiring no tedious dyeing, and only light soaping, clearing, and finishing operations. By the dyeing processes alone the range of shades which it is practicable to print on one piece is strictly limited by what the mordants and their various combinations will yield with the paiticular dye-stuff used. But in steam colouts there is no limit to the number and variety of shades which may be produced, each colour-box. on the cylinder printing -machine containing the whole ingredients essential to the production and fixation of a separate and distinct shade or colour. In addition to this the steaming propess can be and is extensively employed to supplement, the effect of madder-printed or Turkey red goods by printing steam colours into the whites, produced either by resist pastes or by discharges printed on the dyed texture.

The distinguishing peculiarities of steam colours consist, in printing direct and at one operation on the cloth the whole of the materials of the dye and its fixing agent properly mixed and thickened; and 2d, in submitting the printed cloth to the influence of steam, which effects the fixation of the colour. The effect produced by the com-bined heat and moisture of the steaming process is, in the, case of certain combinations, purely mechanical, while in others a chemical reaction ensues. In the printing of what are termed pigment colours, or, in other words, insoluble coloured powders such as used by painters, they are simply mechanically fastened or glued to the cloth by means of albumen, or some body of similar constitution, which coagulates and becomes insoluble on the application of a certain heat. In the case ot tne regular steam colours an a aniline dyes there is printed on the cloth a chemical mix-ture or solution, which on the application of heat produces a reaction resulting in the precipitation of all insoluble compound in the, fibres, or a volatilization of the solvent medium is caused, so that in both cases the same result—an insoluble precipitate—is produced.

With the development of steam colours efforts have been made with success to improve oil the, original crude and unsatisfactory manner in which the steaming was performed. The old method, still largely employed, consists in wrapping the printed cloth around a perforated cylinder of copper, called a "column," into one end of which a pipe passes for the admission of steam. Around the column are first wrapped several folds of felt, above which comes white calico, next the printed goods, and lastly an outer envelope of white calico. When so prepared the column is set perpendicularly on a steam pipe, a stop cock is opened, and steam is admitted into the interior of the column, which presses through and acts on the printed goods. Immediately on the conclusion of the process the column must be dismounted and the goods run, off, otherwise steam might condense in the cloth and cause certain colours to run.

The most common arrangement for steaming, however, consists of the chest or "cottage," which is a cylindrical steam-tight chamber, into which a carriage is introduced. The carriage is mounted with a series of rollers on which the pieces to be steamed are hung, or, in a different arrange-ment, the cloth is fastened on a range of hooks projecting from a steam pipe. In the latter arrangement the hooks are heated by steam before the carriage is thrust into the chest, to prevent condensation of steam on the cold spikes, and consequent rust-staining of the cloth. Fig. 7 shows a sectional view of an ordinary steaming chest by Messrs Mather and Platt. A represents the body of the chest ; B the steam-tight door, which draws up when the chainber is to be opened; C the carriage or waggon fitted with a range of square wooden rollers E. The rollers are all geared to move by means of a cog-wheel F, which is turned by the attendant outside the chamber. The carriage is run in upon the rails D; steam is admitted by the perforated steam-pipe G; H is a tap for running off condensed water, and J is a safety-valve. While one carriage is in the chamber another is being filled and prepared outside to take its place when the goods are sufficiently steamed.

The steaming chest is at best only a crude and discon-nected manner of performing one process in printing, and as all the others are continuous, it forms an awkward break in theseries. To obviate this, and to secure expedi-tion and continuity, a method of steaming has been devised by M. Cordillot of Moscow and Mr William Mather of Salford, which they patented in 1874. Their apparatus,, of which a sectional illustration is shown in fig. 8, they claim will effectually steam 1000 pieces of 25 yards per day. According to their specification, it consists of a, brick or other chamber a, the roof of which is lined with a curved steam jacket b, connected by side pipes c c to the perforated pipe d near the floor. At each end of the: chamber a is an opening closed by a steam-tight door e, through which openings the waggons for receiving the steamed fabrics are admitted and discharged. The fabric is fed into the chamber a over the feed roller g and between the small guide roller or tube h and copper troughs i and i, both of which and the tube h are heated by steam and project on each side of the wall to collect any moisture that may run down. When the fabric is in the chamber it is carried around three or other convenient number of rollers marked j, the last of which delivers it into one of the waggons f." The rollers are all heated by steam to prevent condensation, and as very moist steam is required for some colours, the supply pipe passes through water before entering through the pipes q into the curved jacket b, and thence going by the side pipes c c into the perforated pipe d as before described. "When the apparatus is in operation the steamed fabrics are deposited in one of the waggons, as shown in the figure, and when one is full both end doors are opened to allow the last waggon near the left-hand door to be discharged and to move the full waggon one step towards the exit door by the introduction of an empty waggon through the right-hand door; this brings another waggon in position for receiving the steamed fabrics, and while this is being filled the full waggon (after the four empty ones introduced to fill up the chamber at starting have passed through) that had been discharged can be emptied and brought back to the entrance door." The waggons are made of strong wire and are heated up before entering the chamber. By this system the patentees affirm that the goods are long enough exposed to the steam to allow the chemical reactions to take place in the cloth, so that the colours neither print off nor run during the remainder of the process, and the fixation is completed while the goods lie in the waggons inside the chamber. This system of steaming is in successful operation in soine Man-chester print-works.

Steam colours include two distinct classes of work—1st. pigment colours, or the series fixed by a mechanical effect produced in steaming; and 2d, ordinary steam colours, in which the fixation is effected more by chemical agency.

Pigment Colours are so named because the tinctorial agents employed are coloured lakes, and the insoluble mineral powders used otherwise as painters’ colours. Only a limited number of painters’ colours are so used, as, for a -variety of reasons, many of thern are not suitable for calico--printing. Colours containing arsenic, for example, and some others which produce brilliant effects, cannot be used on account of their highly poisonous nature. Others are excluded on account of their cost, some are too dull and muddy in colour, and some are liable to tarnish or darken on exposure to light, air, moisture, or other influences. The pigments which are most extensively useful are ultramarine blue, Guignet’s or chrome green, and chrome, orange, all of which are very largely used by themselves or in combination with other colours. Lamp black is also employed for the production of a solid grey, and vermilion-red with some other metallic sulphides are sometimes, though rarely, printed as pigment colours. The principal lakes used are carmine, corallin lake (a derivative of phenol or carbolic acid), black logwood lake, and several others prepared from the dye-woods with tin and alumina salts. The aniline dyes on their first introduction were also worked as pigment colours, and printed with albumen.

The first medium employed for fixing mineral pigments and lakes to calico was a solution of India rubber in coal naphtha, an agent which, so far as clearness and permanency of the printed colour is concerned, was perfectly satisfactory. The steaming, dissipated the highly volatile naphtha and left the thin film of caoutchoue mixed with the colour firmly adherent to the tissue. But the inflammability of the copious naphtha fumes evolved gave rise to many serious accidents, and the method had on that account to be abandoned. No other medium has been found to give so satisfactory results as the protein compounds, of which albumen obtained from the white of eggs is the type. Besides egg albumen, blood albumen, lactarin or casein from milk, and gluten from wheaten flour are used as aaents for fixing pigments. In printing with albumen advantage is taken of its well-known peculiarity of coagulating and becoming quite insoluble at a temperature under the boiling point. It is mixed with the colour and deposited on the cloth in its soluble state, when, by the operation of steaming, it coagulates and remains firmly attached to the tissue, imprisoning with it the particles of colour with which it was mixed. The cloth is not in reality dyed, but has only a coloured pattern mechanically fastened or glued to it. Egg albumen gives the most delicate and clear shades, but recent improvements in the preparation of blood albumen render it increasingly available for bright colours. Lactarin ,and gluten, dissolved by means of caustic alkalies, are used for printing ultramarine and other pigment colours. The length of time that pigment colours, are left in the steaming apparatus varies from half-an-hour to an hour.

Ordinary Steam, Colours.—The essential features of this style consist in printing, direct on the cloth the dyeing material, mixed in proper proportion, with any necessary mordant, and certain acids or salts to keep the mixture in solution. On the application of moist heat after printing, the acid is evaporated or a chemical decomposition takes place in the case of the salt, and an insoluble precipitate is produced in the fibre. Steam colours, possess great brilliancy, but they have not the fastness and solidity of madder-dyed goods. The dyes in the case of steam colours must be in the form of decoctions or prepared extracts of the special chemical tinctorial principles. Such prepara-tions have of recent years come into very wide use, and with the progress of chemical science they are daily attaining greater prominence and perfection, so that the older applica-tion of crude materials is rapidly being supplanted by the use of agents and quality. Thus, as already mentioned, madder extract and artificial alizarin treated as steam or "topical" colours, have largely talken the place of madder root as a dye colour, and by the preparation of artificial alizarin from anthracene, printers are now rendered independent of the vegetable kingdom as a source of their hitherto most important dye-stuff.

As a preparatory to printing, the cloth is mordanted or prepared by passing it through a solution of stannate of soda, and treating with a very weak solution of sulphuric acid which decomposes the stannate, combining with the soda, and leaves the stannic acid (peroxide of tin) precipitated in the fibres. Cloth thus prepared has much purer and brighter shades than simple bleached calico. The common steam colours include black and chocolate from logwood liquor, orange from annatto, yellow from Persian berry liquor and from bark liquor, green from Persian berries and yellow prussiate of potash, purple from logwood and red prussiate of potash, dark red from sapanwood and bark liquor, reds, purples, and chocolate from madder extract and alizarin, and blues from Prussian blue. Iron, alumina, and other mordants are used wvith these colours according to their character and the nature of the shades desired. The solvent principally employed is acetic acid, which readily volatilizes in the steaming process, but oxalic acid is also employed to keep certain special oxides in solution during the printing. Oxidizing agents, as the chlorate or bichromate of potash, are also required for the development of some colours. Steam blue is printed, not by using the Prussian blue colours ready formed, but by effecting the chemical reaction on the cloth itself, which results in the blue colour. In some cases yellow prussiate of potash is used, which yields Prussian blue; again, when the red prussiate is employed, Turnbull blue is the result; but a mixture of both, to which a proportion of ferro-prus-siate of tin, called tin pulp, is added, is the source of the best steam blue. The reaction by which the colour is developed will be understood by instancing the development of Prussian blue from the yellow prussiate. It is mixed with an acid—tartaric, oxalic, or sulphuric—or the whole three combined, and printed on the cloth. In the steaming the added acid combines with the potassium of the prussiate and liberates ferrocyanic acid, which is furtlier decomposed into cyanide of iron, abundant fumes of hydrocyanic acid (Prussic acid) being meantime evolved. On withdrawing the goods from the steaming chest after this decomposition is complete the pieces are quite colourless, but exposure to the atmosphere in an ageing chamber, or passing them through an oxidizing solution, such as the bichromate of potash, develops the characteristic blue of Prussian blue.

Andine Colours.—These colours now constitute the largest and most important section of steam-fixed dyeing materials, and in their behaviour and method of printing they form a class by themselves. The range of aniline colours now embraces almost every possible shade; and in no other department of scientific and technical research has equal activity been displayed within the few years which have passed since these colours were introduced; and the rewards of investigation have been commensurate. The number of colours introduced, and the methods of preparing them which have been suggested are beyond computation, and the list of those which are now in current use is exceedingly extensive. In addition to the dyes procured from aniline many more of an allied nature are prepared from other derivatives of coal-tar, plienol, naphthalin, and anthracene, some of which have also come into extensive use, and the applicability of others has been demonstrated. The topical use of these colours in connection with extract of madder, Guignet’s green, ultramarine, &c., has exercised a powerful influence in improving the art of design in connection with calico-printing, placing as they do at the disposal of the designer an unlimited range, of the most striking, brilliant, and pure colours.

Aniline colours have a powerful affinity for animal substances, dyeing silk and woollen tissues readily without the intervention of any mordant. Taking advantage of this property aniline colours were, on their introduction, printed as dye colours, albumen being used as a mordant. An albuminous solution was printed and fixed on the cotton, and on its introduction, so prepared, into the dye-vat the albumen readily took up the colour, while the unmordanted portions merely imbibed an easily discharged stain. Aniline colours were also printed with albumen in the, manner already described as applied to pigments and coloured lakes; and the patents secured by Mr Walter Crum, in 1859, for the application of gluten and lactaxin in printing had chiefly to the use of aniline colours. The process of fixina these colours now generally adopted is known as the arsenite of alumina process. In this process the dye is dissolved in water or acetic acid, carefully filtered through a fine cloth and mixed with acetate of alumina, a thickener, and arsenious acid dissolved in glycerine. This mixture is printed on the cloth, which is then introduced into the steaming chest. In the steaming, acetic acid is liberated and arsenite, of alumina formed, which with the aniline colour is precipitated in the fibres as a brilliant insoluble lake.



SPIRIT COLOURS.

This style of printing consists simply of a modification of the process for ordinary steam colours, but excluding the steaming. All the decoctions and extracts used for regular steam colours may be employed in this method, but they are miyxed with such large proportions of the mordants and acids that were they submitted to the action of steam the fibre wculd be quite destroyed. When printed, spirit colours are therefore simply dried and aged for several hours, after which they are rinsed in water, washed, and dried. The style yields very brilliant but very loose and fugitive colours, and is now falling into disrepute.



FINISHING PROCESSES.

After the prints have undergone the various operations described above, they are submitted to a series of processes, whose object is to give to the fabrics such an appearance as will please the eye of the buyer. All the finishing processes have one common end, namely, to fill up the interstices which exist in the fabrics, and thus give to the calico a more substantial and glossy appearance; and this is effected by filling the cloth with boiled starch, farina, or sour flour, which is obtained from wheat flour which has been allowed to ferment. To these are ofter added large quantities of sulphate of lime or baryta, and other similar substances, with the object of imparting to, the cloth a weight and appearance of solidity which it doe& not really possess. The finishing processes are varied according to the nature of the print, muslins requiring a quite distinct inethod of treatment from ordinary calicoes, and furniture chintzes also receive a finish peculiar to glazed goods. Some of the apparatus employed in finishing will be found flaured under the heading BLEACHING, where also the subject is entered into in some detail. As the general features of finishing, including water-mangling, drying,

damping, starehing, and calendering are the same both for white cottons and prints, it is unnecessary here to detail these operations. The machines and operations in a finishing-room may be briefly noticed as follows. The good are opened by passing over a wilich at a considerable eleva-tion, and if necessary stretched in breadth on a machine which evens the texture and draws it out laterally. They are then passed into the chloring machine, which has two rollers, one of brass and one covered with india-rubber. The lower one is made to revolve in an aclueous solution of chlorine, and as the cloth passes between the rollers it is saturated with this solution. It passes immediately through a box containing a vapour of steam, which at once arrests the action of the chlorine, the momentary contact being con-sidered sufficient to brighten the white ground without giving time for the colours to be affected. From the steam-ing box the piece passes through a water mangle, where pure water is spurted on the cloth, and after passing through the trough it receives a hard squeeze to extract as much moisture as possible before the drying is reached. The machine is a range of steam cans, generally made of copper. The next operation is that of starching, the machinery of which is almost identical with that used for chloring, starch paste, however, occupying the Place of the chlorine liquor. The lower roller revolves in and carries up the starch to, the cloth, which passes round the upper rollers and becomes saturated by the squeezing action produced and regulated by the screws and levers of the machine. After starching, the goods pass direct to another drying machine, whence they are taken to be damped by a slight sprinkling of water, which they receive in passing over a simple machine for the purpose, consisting of a rapidly revolving brush throwing up a fine spray. Calendering is the next and final operation, after which each piece is separated and folded up by a plait-ing machine, or hooked by hand. It is then made up in the. ordinary book form, and after being pressed in a screw or hydraulic press is ready for the market. (J. PA.)



The above article was written by James Paton, F.L.S.; Superintendent of Museums and Art Galleries of Corporation of Glasgow from 1876; Assistant in Museum of Science and Art, Edinburgh, 1861-76; President of Museums Association of the United Kingdom, 1896; editor and part-author of Scottish National Memorials, fol. 1890.




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