SINGEING. This is the first operation to which the cotton ware must be subjected. By it, the fine down which covers the wefts, and is of great inconvenience, especially for printing, will be removed from the ware. The old method consisted in turning the ware quite equally by means of rollers upon a cast-iron half cylinder or on half-cylindrical plates, which are heated from below, and are therefore red hot. The goods are generally singed twice; at first upon the side which is to be printed, and then upon the other. Much better than the process of singeing with icd-hot cylinders is that of employing for the same operation an intense flame. An alcohol flame is too expensive; the flame produced by oil attacks and injures the weft far too seriously to make it practicable. The most suitable flame is that of gas. The gas must be employed to proceed from an iron tube which has a series of small apertures beside each other, so that we obtain a flame of some length when the gas is ignited. Above this tube a horizontal tube is supported, which is, in construction, similar to a channel, and has an opening fronting the previously-mentioned tube. This channel is combined with other vertical tubes, and causes a strong draft of air, by which not only the products of combustion are removed, but the flame is also caused to pass over the meshes of the weft, and thus to consume all the down on the upper side of the weft. Hence, when gas is employed, the operation of singeing must be performed but once. If the gas were to proceed directly out of the openings of the horizontal pipe, we would obtain the desired continuous flame, but it would ignite and render the weft black by its soot. To prevent this, there is inserted above every small opening from which the gas proceeds, a wide metal tube in a vertical position, so that it forms a right angle with the horizontal tube above. These wide tubes that are placed over every opening, have at their base two openings on each side. When the gas now proceeds out of the previously-mentioned small apertures, and a light is held over the upper end of the wide tube, so much air is drawn into the tube and mixed with the gas by means of the openings on the sides of the wide metallic tube, that the flame produced will not ignite fully, but burn with a weak blue light, which is free from all superfluous carbon, and will therefore not soot the weft. This sort of burner is generally known as the " Bunsen burner," and is the invention of the celebrated chemist of that name These Bunsen burners are generally employed in laboratories; at present they are, however, used also for domestic purposes whenever anything is to be heated without being covered with soot. The entire horizontal tube is then covered with these burners, placed alongside of each other. Then, when the gas is turned on in the burners, and a light applied, a long blue flame is produced, which, though it is devoid of full brightness, and not perfectly ignited, gives a very intense heat. Moreover, while the results attained by these burners are far more favorable than without them, the gas consumption is also less when they are employed. Until quite recently the goods were drawn over the top of the gas flames. The top of the flame being, however, everywhere a little higher where there was a burner below, the weft that was drawn across was necessarily singed irregularly, that is to say, either it was singed imperfectly at some spots or burnt at others. A French manufacturer of machines, Mr. Tulpin, of Rou-en, has lately introduced another mode of drawing the goods through the flame. He does not'draw the goods over the top of the flames, but places on each side of the flame a metal roller, whose surface is touched by the flame. Over these two rollers he draws the weft, which no longer meets the top of the flame, but the sides. These sides of the flame can very readily be obtained of perfectly regular dimensions, and thus the goods are singed quite well and without any fault; they can, of course, be singed twice by one flame, if they are drawn the second time over the roller on the other side. By a simple construction it may be caused to touch the flame with its upper side the first time, and afterward with its lower side. After being singed, the goods are subjected to the second preparatory operation, namely, bleaching. This process must be divided into two parts. The manipulations in the first part have the purpose of removing from the weft the resinous substances, gum, and fat, contained in it by nature, as also those substances which were added in the process of manufacturing. The operation of the second series embrace the bleaching, par excellence, by these operations, both the coloring matter, contained by nature in the fiber, and that which was added to it in the processes of spinning and weaving are removed. THE NEWEST BLEACHING PROCESS EMPLOYED IN MOST MAN UFACTORIES. It is necessary here to remark that the weights, as they occur below, are calculated with reference to a quantity of 60 yards of cotton ware. (1.) The ware is at first boiled for five hours in the steam apparatus, whose description will be given further on, with lime milk. The tension of the steam must amount to at least 3—3 atmospheres. The lime milk may be produced by combining with 80 lbs. of lime as much water as is necessary. The ware, after being boiled in the lime liquid, is cooled in the same apparatus with cold water, and then washed. (2.) The goods are now placed from 7 to 10 hours in a bath of hydrochloric acid, 2 strong, according to Baume's areometer. After being sufficiently treated with the hydrochloric acid, the goods pass through the washing machine, and are (3) boiled with resin soap in the same steam apparatus. The resin soap necessary for this purpose is obtained by boiling 120 pounds of colophonium with a solution of 20C pounds of soda-ash. When the goods are thoroughly boiled the liquid is allowed to pass off, and the cotton is treated (4.) again with resin soap. This time the boiling operation must be continued for 4 hours; the same quantity of resin soap must be employed as in the first boiling operation. The same liquid may be used on the next occasion for the first boiling of the cotton. After this second boiling of the cotton ware with resin soap, the goods are either immediately washed or boiled for some hours in a solution of 200 lbs. of soda crystals. They are then washed and passed into the bleaching fluid. It is especially advantageous to perform this operation of boiling with soda crystals, when the water contains considerable quantities of lime, and hence a precipitation of Hme soap might result. (5.) The bleaching fluid with which the ware is now treated, is a solution of bleaching powder (hypochlorite of lime), with a specific weight of 1,025, the specific weight of the water employed being 1,000. In this liquid the goods remain from 7 to 10 hours. (6.) They are then washed and brought into a bath of hydrochloric acid. After remaining here for a similar length of time, as in the preceding case, and being washed, they are dried, either by suspending them in some apartment, or by means of a steam-drying cylinder. In t.b.6 operations designated above by the numbers 2, 5, and 6, the liquid with which the goods are treated from 7 to 10 hours is allowed to pass off some 3 to 4 times into a wooden vat below, and then again poured, by means of a pump, upon the goods. By this circulation of the fluid, the important advantage is gained that the cotton becomes more thoroughly impregnated, and therefore will be more equally bleached. The fluids mentioned above must, of course, be replaced by fresh liquid every time that a new quantity of goods is to be treated. THE- STEAM APPARATUS AND ITS USE. The drawing appended to this article represents the apparatus, we may therefore immediately proceed to the discussion of its use. The bottom of the large boiler is covered with stones, and then the entire boiler is filled with the goods, in such a manner, moreover, that no empty space remains between the folds of the weft. The more the pieces of goods are pressed against the sides of the boiler, the better and more equally the boiling will proceed. When the boiler is filled, some layers of ordinary linen cloth are placed on the top of the cotton ware, and are in turn pressed by the addition of some stones. Then the manhole, R (see the drawing), is closed, the' cock, I, opened, and steam allowed to enter through the cock, D. As the steam enters, it presses down the pieces and removes the fluid adhering to the ware, as also the atmospheric air. When the steam begins to rush out of the cock, I, this cock is allowed to remain for some minutes open; in this time the lime milk or the resin-soap solution is introduced through the cock, M, into the boiling vesssl, B; these liquids are heated by steam, which enters through the cock, E. The cock, D, is then closed, so that the boiler, A, is in no combination, either with the steam tube, C, nor with the tube, H. After some minutes, when the tension of the steam in the boiler, A, is reduced by cooling, the cock, I, is closed, and the cock, D, opened, so that this boiler, A, is brought into connection with the tube, H. Then the pressure of the steam in the boiler, B, drives the fluid from the boiler through the tube, H, over the goods contained in the boiler, A. When the entire fluid has been driven from B into the boiler, A,— which may be observed by the glass tube,- J,—the cock, E, is closed, so that the boiler is in combination neither with the steam tube, C, nor with the steam tube, G. Steam is now allowed to enter the boiler, A, and after some minutes, during which time the pressure of the steam in the boiler, A, rises, the cock, E, is opened. As the drawing shows, this cock connects the boiler, B, with the tube, Q. In this manner the steam drives the fluid through the goods and through the tube, G, back into the boiler, B. It is necessary that during this process the air-cock, L, of the boiler into which the fluid is driven, be opened. At the same time equal caution must be observed in closing it in proper time, as otherwise the entire fluid might escape by means of it. When the entire fluid is again in the boiler, B, which may be observed by the glass tube, J, the steam is shut off and again passed into the boiler, B, to heat the fluid contained in it, and to drive it a second time into the boiler, A. The operation described above is repeated for a period of four hours, which time suffices for a thorough treatment of the goods. Finally, the outlet-cock, I, is opened, and when the steam has driven the fluid out of the boiler, A, it is allowed to rush through the boiler for some minutes more, and then shut off, after which the air-cock, L, is opened. As soon as the steam in the vessel, A, has lost its pressure, the manhole is opened, and the goods cooled with cold water. In fill ing the boiler, B, a little space must be left, in order that the fluid may expand. The proper dimension of the space to be left free is readily determined by the glass tube, J. SHEARING THE WARE. The shearing operation has as its purpose the removal of that portion of down, which is fixed by weaver's glue, and therefore not destroyed by singeing; it rises again after the removal of the glue by the bleaching. The shearing machine, which is most frequently employed, is that with the vacillating cylinder. The sheaving apparatus consists of a knife, from 3 to 4 feet long, and a wooden cylinder parallel to it, in which are set steel rails, formed like coils. The cylinder receives a rotating motion, backward and forward, by a simple mechanism. The knife raises the down, while the knives, set in the wooden cylinder, cuts it off. For removing the down which has been sheared, a brushing apparatus is employed. The ware is wound up after this operation, and is now ready for printing. FINISHING, LAYING, AND PRESSING THE COTTON WARE. The majority of cotton ware, whether it be white, dyed, or printed, must, before bein ready f jr trade, receive a certain degree of stiffness and smoothness—that is to say, it must be finished. Finishing is effected with a moro or less solid starch paste. In some cases thi3 paste must be transformed by the addition of a little bleaching powder in solution into Leiscome. If the goods are to be bright, it is necessary to add to the starch paste some way, stearine or spermacetti. As cotton always receives through the bleaching process a certain yellow shade, it is passed through water in which some ultramarine is in suspension, ?nd then finished. It is also possible to add for the same purpose a quantity of ultramarine to the starch paste with winch the finishing is effected. The pieces, after being starched, are calendered to impart to them a certain degree of smoothness. Previously, however, the pieces must be moistened. This moistening of the ware is effected by entering it into a sprinkling machine. This consists of a cylindrical brush, the hairs of which dip into a vat below the brush, which is filled with water. The brush, when brought into rotation, rapidly throws a rain of small drops over the ware. The pieces are then allowed to lie quietly for some time, so that the moisture may extend over the whole surface of the ware. This moistening operation can be entirely dispensed with if in the course of the finishing operation there bo, added to the mass some hygroscopic salt, that is, one that attracts moisture from the atmosphere. If, for instance, the mass is allowed to contain a small quantity of hydiochlorate of lime, and is allowed to lie quietly for some hours in a cool room, so much moisture is attracted as to render the sprinkling unnecessary. A finishing mass, which can altogether dispense with the sprinkling, may be composed as follows : In 25 gallons of the starch paste are dissolved 100 grammes (one-fifth of a pound) of hydrochlorate of lime. A weak finish is produced by allowing the moistened pieces to pass through a calender in which the roller in the middle is covered with felt or cloth. For obtaining a glazed finish, a machine is used consisting of 3 rollers, the upper and lower one of which are made of paper, that in the center of cast iron. This latter roller is hollow, and can be heated by steam. By means of levers or screws these rollers can be pressed more or less compactly together. For the glazing finish the so-called friction calender is used. This glazingf machine differs from the above-mentioned machine merely in the more rapid rotation of the hollow iron roller in the middle, which is effected by the insertion of an additional wheel in the mechanism. For rendering the wefts similar to silk mohair, two finished pieces were formerly laid together and allowed to pass through the calender. By the pressure of the rollers of the calender, as the threads of the one piece are not parallel to those of the other, and therefore cross each other, the latter threads are pressed quite smooth, and a beautiful effect is thus produced. At present there are suitable machines employed for this purpose. They consist of a leathei, paper, or wooden roller, and an engraved cylinder of copper or brass. Before the ware is passed through the machine, the pap.er or wooden roller must receive an impress of the engraving OE the metal cylinder; this is effected by pressing the two rollers strongly together. By employing a suitably-engraved cylinder all kinds of weft, as moreen, huckaback, quilting, reps, etc., may be readily imitated. Fine wefts, as jaconets, organdy, batiste, which are prone to contract, and whose threads often are drawn apart, must be strained after the process of finishing. The pieces, when finished and calendered are laid in certain layers, then sewed, marked, and finally pressed for some hours under a screw or hydraulic press. The glazing finish is composed of 50 gallons of water, 40 kilogrammes of starch, and 2 kilogrammes of stearine, which which ubstanees are boiled together for from 5 to 6 hours. THE San Francisco Mechanics' Institute will open its Seventh Annual Exhibition, next September, in a building cover ing 70,000 feet of ground, and erected special ly for the purpose at a cost of $45,000.
This article was originally published with the title "The Preparation of Cotton Ware for Dyeing and Printing" in Scientific American 20, 21, 326 (May 1869)