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that a full-time analyst will be put in charge, who will do routine analysis connected with the various researches, prepare solutions, etc. Small BALANCE ROOMS which can be kept free from moisture, carbon dioxide, etc., open off the analysis room. The COMBUSTION LABORATORY, Room 2 13, adjoins the analysis room. It is equipped with organic and carbon combustion trains, multiple unit electric tube, crucible, and muffle furnaces. The ORGANIC LABORATORY, Room 2 2 2 , is fitted with a Kjeldah1 rack, thermostats, and the general equipment of an organic laboratory. This laboratory is not connected with the organic department but is for the convenience of those who need to do organic synthesis, etc., incidental to theoretical and technical researches. TECHNICAL LABORATORIES
The TECHNICAL LABORATORIES, Rooms 21, 2 2 , 121, and 221, form in effect a four-story factory. The upper room is equipped for the analytical control of technical operations, the factory laboratory, and a part of the room is reserved for large apparatus. The main room (Fig. 1 2 ) contains a steam table, a drying closet, a large shelf dryer, 8 in. and 15 in. International basket centrifuges, a large International centrifuge, two 250-lb., jo-ga!. jacketed autoclaves, two 2-gal. autoclaves, combination column still, extractor, condensers, etc., Kestner type evaporator, a 500-gal. tank, 5-gal. and 25-gal. jacketed cast iron kettles with extension pieces and covers. The kettles may be combined to make such pieces as vacuum pans, vacuufn agitators, vacuum crystallizing evaporators with or without agitation, nitrators, sulfonators, etc. This equipment is being added to very rapidly. The heavy technical rooms, Nos. 21 and 2 2 , contain a steam boiler, a cement kiln, a suction filter, a filter press and grinding machinery. The ELECTROCHEMICAL LABORATORY has been already partly described. Operations are worked out on a small scale in Room 119 (Fig. IO), and on a larger scale in Room 19 (Fig. 9). This room is provided with a traveling 2-ton Peerless hoist. A large stock of electrodes, refractories, and materials for furnace construction are carried in Room 11. The steel has been omitted from the floor in order to diminish eddy current losses. The furnace laboratory houses several gas and oil furnaces and a Herreshoff mechanical pyrites burner with six 24-in. hearths. STORES Stores are distributed from Rooms 214 and 216. Only a small number of instruments of general use are here. Most of the apparatus is stored in apparatus closets built in the laboratory in which it is most often used. A large room, No. 32 I , is provided for large set-ups temporarily out of use. All apparatus and stores are catalogued by the number of the room, a section letter, and shelf number. This number appears on the apparatus, and a tag giving the temporary location is left in the permanent location when the instruments, etc., are in use. It is the policy of the laboratory t o keep all apparatus in use, and easily available day or night. I n this brief outline only those features which are unique in laboratory construction and equipment have been described. The accompanying photographs are designed to show certain of the rooms as they appear under actual working conditions. UNIVERSITY OF CALIFORNIA BERKELEY
DYEING OF KHAKI IN THE UNITED STATES' HISTORICAL AND THEORETICAL By
JOHN
C. HBBDEN
The khaki-dyed fabrics are used almost wholly for military purposes. The use of this color for uniforms had its origin in the Boer War. The peculiar shade of the terrain of South 1 Address delivered before the New York Section, Society of Chemical Industry, May 24, 1918.
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Africa made it possible to conceal the presence of troops from the enemy by adopting a shade for uniforms which blended with the color of the landscape. Military observers, noting the effect of the use of this kind of uniform, gave their attention t o its development in other countries. The history of the dyeing of khaki is spread through the literature, and really originates in the first patents taken out by Gatty in Great Britain in 1884. It was not, however, until 1897 that the development of this color was taken up seriously. The British dye houses then began to give particular attention to the production of this color, both on cotton and wool. At about the year 1900 the American Government took up the use of khaki-colored fabrics for the manufacture of tents, kits, and uniforms. From that time there has been a steady development in the improvement of both the shade and quality of the fabrics. The early shades of khaki used by the American Government were comparatively light and of a greenish yellow tone. This shade was changed t o a darker and more yellow brownish khaki. As the German field gray came into use, our Government adopted what is now known as the olive-drab. At the present time the three shades of khaki seem to be in use. When the use of khaki was taken up by the American Army, our soldiers were clothed in uniforms made from woolen fabrics. Although the quality of the wool used was the best, such fabrics, in order to have strength, were of necessity heavy. Mr. T. B. Owen, between the years 1900 and 1902, while he was acting as superintendent of the Atlantic Mills in Providence, R. I., called t o the attention of the Quartermaster's Department the superiority of worsted fabrics or worsted serges, particularly for the manufacture of blouses and shirts. These fabrics were tried by the Army and found to be superior to the woolen fabrics. To-day there is scarcely any woolen fabric used, except for blankets and overcoats. Khaki is usually dyed on cotton or wool. The production of a khaki shade on silk is required so infrequently that methods for producing this color on this fiber need not be discussed. The dyeing of khaki both on cotton and wool may be classed under the following methods: I-Chemical or oxidation methods for both cotton and wool. 2-Mordant dyeing methods, particularly for dyeing wool, 3-After-chroming methods, or one-bath chrome methods, for wool. 4-Direct or substantive dye methods, with or without aftertreatment, particularly for cotton, but also applicable to wool. S S u l f u r color dyeing methods for cotton. 6-Vat color dyeing methods for cotton. The chemical or oxidation method generally used for dyeing cotton cloths or yarns for khaki-colored fabrics, for use in uniforms, tents, and kits, is based upon the production in and on the fiber of a mixture of the oxides of iron and chromium. Before the shades thus produced were used for military purposes particularly, these dyes were usually designated as iron buffs. The browns produced by the use of salts of manganese, usually called manganese bister, are too deep and too red to be used as khaki shades or as the basis for khaki colors. In the production of khaki by this method, the cloth is padded or saturated with a mixture of iron and chromium salts, and then, either with or without ageing, is passed into a solution of an alkali in order to precipitate the mixture of iron and chromium oxides in and on the fiber. An alternative method is to pad or saturate the cloth, dry a t a low temperature, age in an ageing machine, and then pass into a solution of alkali in order to precipitate the oxides and produce the khaki color on the fiber. In the padding or precipitating method, when the padded or saturated goods are not dried, it is necessary t o make several passages of the fabric through the solutions of the salts of iron and chromium, and through the alkaline solution. When the method in which the cloth is padded, dried, and aged before
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treatment with alkali is used, it is rarely necessary to make more than one passage through the different solutions. Thus i t will be seen that while it is necessary t o have special machinery and equipment in order to dye khaki by the short method, it is more economical and the shade of color can be more easily controlled. The first method described may rightly be termed the wet method, and the second the drying method. The following recipe may be given as an illustration of the wet method: 75 25 5 5
Ibs. chrome alum are dissolved in gal. water. To this solution are added qts. commercial nitrate of iron, 90" T w . qts. commercial pyrolignite of iron, 2 5 O Tw.
The goods are first thoroughly boiled out, or half or full bleached, as may be required for the particular fabric. They a r e then padded in the above solution, so that the fabric is thoroughly saturated. After padding, the goods are passed through a boiling solution containing 6 ozs. of calcined carbonate of soda per gal. The passage through the iron and chrome salt solution, followed by the passage through the alkaline solution, may be repeated 4 or 6 times before a full shade of khaki is produced. After the depth of shade required is obtained, the goods are thoroughly washed to remove excess of alkali and to prepare them for any after-treatment required. To produce a khaki color by the drying method, the following recipe will serve as an illustration. 10 gal. acetate of chrome, 32' Tw. 5 gals. pyrolignite of iron, 20" Tw. 10 gals. water are mixed together
The goods are padded in this solution, and dried a t a low temperature. The goods may then either be passed through a boiling solution of carbonated soda or passed through an ageing machine after drying, and then through a boiling solution of carbonate of soda. One passage through the solution of chrome and iron acetates will produce a full or medium shade of khaki. I t is rarely necessary to make two passages through the acetate solution. Many modifications of the typical recipes given above have 'been used. These modifications have been attempted principally t o modify the shade, i. e., t o make a color more olive in tone, and also to increase the fastness of the color produced to the chemical tests to which the fabric is subjected, after dyeing. Thus, attempts have been made to add other salts than the salts of chromium and iron to the bath, with the idea of increasing the fastness to acids. None of these attempts, however, have been particularly successful, so that it is safe to say that the chemical or oxidation khaki on cotton cloth or cotton yarn is produced b y the we of a mixture of iron and chromium salts. It is to be noted, however, that goods dyed with acetate of iron, or with iron salts other than the pyrolignite, are liable to become tender i n storing. This is due to the gradual oxidizing and deoxidizing Qf the iron oxides formed in the dyeing process, this oxidizing process being accelerated apparently by the cotton fiber. When pyrolignite of iron is used, the impurities contained in this product seem t o have a modifying action upon the oxidation process and less tendering is observed. Khaki colors when dyed by either of the above methods or modifications of these methods are not particularly €ast to acids, and do not meet the tests in this respect required by the military authorities. The colors, however, are very fast t o light, scouring, washing, and the ordinary treatments to which the fabrics are subjected. Many attempts to render the khaki-dyed fabrics, when dyed by'the iron and chromium method, fast to acid, have been proposed. These methods consist in after-treating the dyed fabrics with various salts or acids, as, for instance, copper salts, boracic acid, tungstates, etc. hTone of these methods have
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produced a fabric which would meet the tests. The only method thus far published which will produce an iron and chromium khaki fast to acid is the one patented by Gatty, which consists in treating the steamed goods with a solution of silicate o€ soda. Yery fast bronze colors are produced on cotton by oxidizing on the fiber meta-phenylene or meta-tolylene diamine. A typical recipe for producing these so-called fast bisters or browns is the following: 1 lb. phenylene diamine hydrochlorate or acetate lb. chlorate of soda ' / z Ib. yellow prussiate of soda are dissolved in one gallon of water 1/z
Pad the well-boiled or bleached goods through this soluiion, dry a t a low temperature, pass through the ager, wash and soap. The color may be modified by making various additions of oxidizing agents to the solution, or by adding various bases, as, for instance, alpha-naphthylami'ne, aniline salt, diamidodiphenylamine, sulfocyanate of ammonia, or even salts of iron and other compounds, which will produce dyes on the cotton fiber by the above oxidation method. These colors, although remarkable for their fastness to light, scouring, and acids, have not been produced successfully in a large way, owing to the fact that the padding solution is constantly oxidizing and changing in composition. The color is thus produced in the solution before the fabric is wetted, and dried. In the case of phenylene diamine, the oxidation is so rapid that in order to obtain results i t is necessary to make up the various solutions of ingredients separately, and mix these solutions together in the proper proportion as they are fed into the padding machine. This involves so much care and attention that the process does not seem to be suited to our manufacturing conditions. 'The author has made many attempts to overcome the oxidizing action in the solution, but thus far there seems to have been no method devised which will make i t possible to make a comparatively permanent solution, as is the case in the solution used in dyeing aniline black by this same method. We may safely say that the iron-chromium method for dyeing khaki on cotton is the only chemical or oxidation method in practical use. For the dyeing of khaki, however, on wool, both the iron-chrome method and the diamine method have been used very successfully. The dyeing of khaki colors on wool or worsted yarn or tops, with a combination of iron, chromium, and manganese salts was worked out a t the Atlantic Mills in Providence, R. I., in the years 1900 and 1902, by Mr. Herbert Fulsom, who was then chemist for the company. The details of the process were not made public. Mr. Fulsom succeeded in producing a color which was free from the harsh feel iisually produced in mordanting wool with iron. This permitted the wool dyed after his method to be drawn and spun in the usual manner, and t o produce yarns of excellent quality. The color was extremely fast to light, washing, and scouring, but was not remarkably fast to acid treatment. Its fastness in this respect, however, was sufficient to meet the Government test. The shade of khaki in vogue a t that time was much lighter than the dark shade used a t the present time. It would hardly have been possible to have produced as deep a color as is required by this method. Furthermore, it is not possible t o produce the olivedrab by this method. In 1903 and 1904, the author produced a t the Peacedale Manufacturing Co., Peacedale, R. I., an oxidation khaki based on the diamine method. This color is remarkable for its fastness to light, scouring, fulling, acids, reducing agents, and rubbing. The maximum shade produced by this method is too light to match the shade of khaki now in vogue. m e n darker shades of color than the shade used a t that time were attempted, this method failed. The process, however, can be used on tops,
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yarns, or piece goods; the shades produced are remarkable in that they are level and uniform. The fiber is particularly soft, and spins practically as well as white wool. The method used is as follows: For 450 lbs. worsted tops: Add to the dye bath the following products in the following order: 5 Ibs. meta-tolylene diamine dissolved in 6 gals. acetic acid, No. 8
After the addition, enter the goods into this bath, keeping the temperature a t about 1 2 0 ' F., and work the goods for 15 to 20 min. t o allow the fiber to take up the diamine. Lift the goods, and then add the following solution: 71/2
lbs. ferric chloride
18 Ibs. chromium chloride or fluoride 121/? lbs. chlorate soda
Bring the bath to the boil, and work in the boiling bath until the shade is produced. The goods are then thoroughly washed, and need no subsequent treatment to prepare them for the spinning operations. The khaki thus produced is the fastest for the depth of shade of any of the dyes known to date. Before discussing the mordant dyeing after chroming, one bath chrome, and the direct dye methods for the production of khaki shades, l e t us consider the relation of fastness t o scouring and alkali to the chemical constitution of dyestuffs in general. From a careful study it will be seen that the fastness to scouring and alkali depends upon the chemical constitution of the dye molecule, and upon the nature or chemical reactivity of the elements or molecules substituted in the nucleus or nuclei of this molecule. The substitution of halogen, nitro groups, amido groups, sulfo groups, hydroxyl, carboxyl, and other groups, not only react as chromophoric radicals, but modify the chemical reactivity of the dye molecule. These substituted groups thus determine the dyeing properties of the compounds, the fastness of the colors produced to scouring and alkali, and also modify the shade due to their chromophoric character. From a study of these substitutions in the molecule, the dyeing properties and fastness to scouring and alkali can be predicted, Generally speaking, a dyestuff, in order to be applied to the fiber, must be soluble in water. This solubility is generally dependent upon the substitution in the molecule of a sulfo, hydroxyl, or carboxyl group. If these groups be present and are not in the ortho position, the solubility of the dyestuff, even after being dyed upon a mordant or fixed by after-treatment, may be sufficient to render the color not fast to scouring. There is a class of colors containing an amido group in the molecule which, after the dye is fixed upon the fiber, can be diazotized and developed, as it is termed. If there are too many sulfo, carboxyl, or hydroxyl groups in the molecule, the color, produced, even after developing, is not fast t o scouring. The fastness to scouring and alkali is decreased in proportion to the increase in the number of these groups substituted in the dye molecule. Colors fast to scouring and alkali cannot be produced unless tliose groups which are capable of dyeing upon a mordant, or being after-treated after the dye is fixed upon the fiber, are present in the molecule and are in such a position one t o the other, that definite compounds can be produced by combining with the mordant or by the after-treatment. The sulfo groups of a dye molecule cannot be treated by any reagent now known, which will render them fast to scouring or alkali. Neither can the hydroxyl or the carboxyl groups be treated and made insoluble unless they be in the ortho position one to t h e other. Thus, two hydroxyl groups, one hydroxyl and one carboxyl group, and certain hydroxy azo groups, when in the ortho position, determine the property of fastness to water and scouring when the dyestuff is either dyed upon a mordant or aftertreated with a compound which will render the color insoluble. Kostanecki showed that the property of dyeing on a mordant, possessed by certain color acids, was due to the fact that those
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color acids which dye on a mordant, have either two hydroxyl groups in the ortho position in the molecule, or a hydroxyl and a carboxyl group in the ortho position, or that the compound was an orthonitroso, or orthoquinone oxime. When the dyeing method now known as the after-chroming method was studied and analyzed with reference to the chemical constitution of the dyestuffs, it was found that the ortho position was the determining factor. Thus, orthodihydroxy, peridihydroxy, orthohydroxycarboxy, and certain orthohydroxyazo dyes were all not only modified in color, or developed in shade by aftertreating the dyed fiber with bichromate or by dyeing with chromate or chrome salts, but they all had distinct mordant dyeing properties following the Kostanecki rule. Not all dyes, however, which meet the requirements of the Kostanecki rule, or those which may be after-treated, are fast to scouring. This lack of fastness is due to the modifying influence on the solubility of the dye, of the groups substituted in the molecule other than those which give the dye the mordant dyeing or after-chroming property. These substituted groups have sufficient influence upon the solubility of Ihe after-treated or mordant-dyed color, to render the dye produced not fast t o scouring and alkali. To illustrate these facts, a few concrete examples may be cited in order to show the relation of dye constitution to the production of fast khaki shades. Alizarine is an orthodihydroxy anthraquinone, the hydroxy groups being in the 1,2 positions. The Turkey red produced by the use of true alizarine is the fastest red to boiling and bleaching. The scarlet reds made from anthrapurpurine and flavopurpurine, as well as the red made from purpurine, are not as fast as true alizarine red made from alizarine. This lack of fastness is due to the presence in the molecule of a third hydroxy group. This group readily unites with any alkali, rendering the lakes formed with the mordant soluble. True alizarine, not having this third hydroxy group, is practically insoluble. Those alizarine blues which are penta- and hexahydroxyanthraquinones are not as fast to scouring as alizarine, because all of these dyes have a hydroxy group which can react as does the hydroxy group in anthraflavine or flavopurpurine. Sulfo, nitro, and carboxyl groups can react in the same way as does the hydroxy group when not in the ortho position. Colors containing these groups are invariably not fast to scouring or alkali unless the sulfonic acid nitro compound, or other compound, in which the group is substituted, is of itself difficultly soluble. An increase in the number of these groups in the dyestuff molecule generally produces very soluble compounds, and therefore the colors produced therefrom are not fast to scouring and alkali. The mordant dyeing methods require two operations: First, the mordanting proper; second, the dyeing. For the production of khaki shades there are really only two mordants which may be considered, oiz., the chrome and titanium mordants. Iron, nickel, cobalt, and aluminum mordants produce, when combined with the proper dyestuffs, khaki shades; but the colors produced fail either in fastness i o light, scouring, alkali, or acid. The colors produced in a titanium mordant are remarkably fast in every respect, but the colors which dye on this mordant and produce khaki shades are very limited. The chrome mordant, however, permits of the use of a wide range of dyestuffs, and has this advantage, that khaki shades can be produced by the chrome mordanting method by the use either of the regular mordanting method, the after-treating method, or by the one-bath chrome method. The chrome after-treating method, and the one-bath chrome methods are the methods usually used. Neither of these methods are applicable to the production of khaki on cotton. The true mordant dyeing yellows, as, for instance, the oxyketone colors represented by alizarine yellow or galloaceto-
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phenone and the yellow dyestuffs derived from dye woods, tannins, and from natural sources, while they can be combined with red and blue mordant dyeing dyestuffs and produce khaki shades, are not fast to scouring and alkali because of the pre’ence ol a hydroxy group in the molecule, which does not unite with the mordant. These dyes follow the rule laid down for anthrapurpurine and similar dyestuffs. The strictly mordant-dyeing dyestuffs are not, therefore, used in producing khaki colors. Many, however, of the acid dyes which produce khaki shades can be dyed on a mordant; but the method is long and does not yield the fastest colors, nor is the method as practical as the aftertreating or one-bath chrome method. The mordant-dyeing method has, therefore, found very little use for this purpose for the dyeing of wool. Except as a printing method it has found no use on cotton. The dyestuffs used for the production of the yellow-orange or yellow-brown used as a basis for khaki, to be shaded to the true khaki shade with blue, black, or green, and with red or a reddish brown, are nearly all azo dyes derived from salicylic acid. The hydroxyl and the carboxyl groups in the ortho position in the salicylic acid molecules give these dyes the property of dyeing on a mordant. They follow the Kostanecki rule in this respect. At the same time, the chromogen in the color, being the azo group, and the substitutions in the molecule being acid in character, the dyes are true acid dyestuffs. They therefore can be dyed either as acid dyes or as mordant dyes, or can be after-treated. Many of these dyes, also, can be dyed by the chrome in the bath method. The fastness of the dyes to scouring and alkali varies in proportion to the numbers of those groups substituted in the molecule, which tend to render the compound soluble. The colors are uniformly fairly fast to light and acid; certain members of the series are excepfionally fast t o all the tests required. The major part of the coloring entering into a khaki shade is yellow, so that the amount of blue and red required to produce a true khaki color, or an olive-drab in conjunction with the yellow or orange or yellow-brown, is very small. For this reason only those dyes, which in very light shades are fast to scouring and light, can be used for shading purposes. As types of the dyestuffs that may be used, the following are cited: Alizarine Yellow-Salicylic acid plus nitro anilines Milling Yellow-Salicylic acid plus amidoazobenzol and its monosulfonic acid Chrome F a s t Yellow-Salicylic acid plus amidocresolether Chrome F a s t Green H acid plus orthoamidoparanitrophenol Acid Alizarine Garnet-Resorcine plus orthoamidophenolparasulfonic acid
Changes may be run on these combinations by using dyes which produce the same relative amounts of yellow, red, and blue when dyed. Thus, the acid alizarine garnet may be in part or wholly replaced by a red-brown; the green by a black or a blue, which yields, when dyed, a fast gray. Again, the yellow derived from the salicylic ,azo compound may be replaced by the fast yellows derived from primuline, which are usually termed chloramine yellows. The khaki colors produced to-day on wool are made from combinations of dyestuffs similar t o the colors enumerated above . The khaki colors produced by the direct or substantive dye methods are in no case, even when after-treated or developed, on cotton or wool, sufficiently fast to pass the Government test. This method of dyeing is used, however, a t times. The combinations of dyestuffs that may be used are almost without limit but the colors obtained are uniformly not sufficiently fast. The dyeing method is simple, involving a dyeing in a salt or soap bath for cotton, or a weak acid bath for wool. The color produced by the direct dyeing may be used as such, or may be after-treated with a mixture of bichromate, sulfate of
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copper, and acetic acid, or diazotized and developed on the fiber, as the case may be. The sulfur colors form an important group of dyestuffs for the production of khaki shades and olive-drab on cotton. The dyeing method is simple and direct, and the fiber is, when properly dyed, uniformly soft and strong. The dyeing method consists in boiling the cotton in a solution of the dye made by reducing the color with sodium sulfide, and adding alkali and salt to this solution in order to fix the dye on the fiber. Dyeings made from sulfur colors should always be thoroughly washed with water, and then soaped and wrung or extracted in the centrifuge, so that sorhe of the soap solution may be left in the fiber, and the fiber or cloth thus be rendered alkaline. This after-treatment or finishing operation is necessary in order to render the fiber soft, and to prevent the oxidation of any sulfide compound which may be left in the fiber. This subsequent oxidation of the dye on the fiber may result in tendering of the cotton. The oxidation and tendering, however, is prevented by the alkaline condition of the fiber. Direct dyeings of sulfur colors are usually not sufficiently fast to scouring and acid to meet the Government requirements. However, if a proper selection of dyes be made, and the direct dyeings made from these be after-treated with a solution of bichrome, sulfate of copper, and acetic acid, colors which meet the ordinary Government test are obtained. The use of mineral acid in this after-treatment may produce a subsequent tendering of the fiber, even though the dyeings be after-treated or finished from soap solution. For this reason, acetic acid only should be used in this after-treatment. The sulfur dyes are all manufactured by empirical methods. The constitution of the colors and the chemical reactions involved in their manufacture are not known. It is, therefore, necessary to select the dyes to be used, only after careful dyeing tests have been made, and these dyeing tests subjected to the required tests for determining the fastness to scouring, alkali, acid, etc. By making combinations of dyes selected from the evidence obtained from such dyeing tests, satisfactory khaki shades can be produced. The sulfur colors are not applicable t o wool. The vat dyes, so-called, because they are dyed in reduced condition in a vat, as is indigo, produce, next to the oxidation or chemical method, the fastest khaki colors. These dyestuffs, when reduced to leuco compounds by the use of hydrosulfite of soda or other reducing agents, and dissolved in alkali, have an affinity for the cotton fiber. If the cotton, either as raw stock, yarn, or in the piece, be immersed in the dye, the fiber will take up the leuco compound from the solution. This dissolving of the leuco coknpound in the fiber continues until the solubility of the compound in the alkaline solution and in the fiber reaches an equilibrium. The equilibrium varies for each dye. If the cotton which has taken up the reduced dye be wrung out to remove the excess solution, and subjected to the action of the air, the leuco body is oxidized, and the color is produced on the fiber. Not all dyestuffs belonging to this class are fast. But there are several which produce the fastest shade known on cotton. From these exceedingly fast dyes, a great variety of very useful shades can be produced. The dyeing method is applicable to raw stock or yarn, and by special methods cotton piece goods may be dyed with these dyestuffs. The colors produced by the fast dyes of this class are fast to the severest scouring and boiling, fast to acids and bleaching, and exceedingly fast to light. The dyeing being performed in an alkaline bath, the cotton fiber or cloth is therefore uniformly soft and strong. In dyeing khaki by this method, the yellow entering into the shade is again the major part of the dyestuffs used. The yellows that may be employed are those known under the trade name of ALGOL YELLOWS AND ORANGES, CIBANONE YELLOWS AND ORANGES,
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and INDANTHRENE YELLOWS By the use of the proper dye methods these yellows can be shaded to produce khaki colors and olive-drab, meeting the severest tests as to fastness. For shading these yellows to produce a khaki or an olive-drab, i t is necessary to use colors of the same class, giving the red or blue-gray tones necessary to produce the shade required in conjunction with the yellow used. The colors available for this purpose are those known commercially as algol corinth, algol red, algol olive, algol brown, cibanone brown, indanthrene corinth, indanthrene brown, algol brilliant violet, and indanthrene blue. By using combinations of these ayes, the fastest khaki shades for cotton are produced. It would be interesting to study the chemical constitution of these dyestuffs, and note the effects of constitution, first, upon the dyeing method, and, second, upon the fastness of the colors produced. This discussion involves so many factors that it is not possible a t this time. The vat colors cannot be used for the dyeing of wool (at least, according to the present dyeing method) because the amount of caustic soda required to dissolve the leuco compounds is sufficient to dissolve or permanently weaken or destroy the wool fiber. The khaki-dyed fabrics, being primarily for military purposes, should be manufactured having in view the production of a fabric of the highest quality, the production of the greatest yardage in a given time, and the manufacture of the cloth a t the lowest possible cost per yard. The specifications have uniformly called for a fabric to be made from wool or cotton dyed in the stock. The production 01 fabrics following these specifications is thus of necessity confined to the mills having facilities for dyeing raw stock. The cost of yarns manufactured from stock-dyed cotton or wool is greater than the cost of yarns spun from white or gray cotton or wool. The quality of the fabrics made from stock-dyed yarns is no better, and frequently is inferior to the quality of piece-dyed goods. The production per unit of machinery of stock-dyed fabrics is lower than the production of gray or white goods. It is the opinion of the author that to procure the highest quality of fabrics, the greatest quantity in the shortest time, and a t the same time the lowest cost, the piece-dye method should be adapted both for cotton and wool and worsted fabrics. A large percentage of the cotton fabrics now used for military purposes is manufactured by the piece-dyeing method. If these goods i r e satisfactory there is n o argument against extending this method of manufacture t o include all fabrics. Serge blues or worsted piece goods, as they are termed, are recognized as standard for quality. There is no valid argument against making khaki-colored serges, dyed in the piece, standard also. When we consider the work done, and the progress made in the dyeing of khaki in the United States, we need not feel ashamed. Our manufacturers have produced fabrics equal to the best foreign goods. Our dyers have developed methods not used abroad, and have accommodated dyeing methods to manufacturing procedure, so that the foreign manufacturer has been compelled to imitate some of the methods developed in this country. We are dyeing cotton piece goods by the iron-chrome chemical or oxidation method, equal in quality to the foreign goods. Our dyers have developed machinery for this process, so that the process may be said to be truly American, as it is practiced in this country to-day. It is true, we have not developed the diamine oxidation process For cotton; but, should economic conditions recommend or warrant the development of this process, it can be safely predicted that the method will soon be developed into a practical dyeing process for khaki-colored piece goods. We have developed both the iron-chrome and the diamine oxidation methods for wool. These methods have been used very successfully, and have demonstrated that the colors obtained are HELINDONE YELLOWS AND ORANGES,
AND ORANGES
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the fastest for the depth of shades produced. It does not appear that either of these methods has been used abroad. The after-treating or chrome-in-the-bath methods are practiced by our dyers, producing goods by the raw stock, yarn and piecedyeing methods equal to the best foreign fabrics. Large quantities of sulfur dyestuffs are used for dyeing raw cotton for khaklrcolored goods, and for dyeing piece-goods producing both the true khaki shades and the olive-drab colored cloth. The dyeing methods generally used are the same as those used abroad, and the quality of the color produced is equal in every respect to the color on the foreign fabrics. We have an American method, however, for dyeing piece goods with the sulfur colors, which permits the dyer to produce a full shade of either khaki or olive-drab by making one passage through the dyeing apparatus. The color produced by the use of this method is equal to the best produced by other methods. This continuous method of dyeing piece goods is not generally in use here, however, and had apparently not been used abroad. We have produced from raw stock and yarn dyed with the vat colors the fastest known shades for cotton fabrics used for military purposes. The fabrics have been manufactured in large quantities, and have proved the value of both the dyeing and manufacturing method used. The continuous process for dyeing piece goods for sulfur colors may be, with slight modification, used €or the dyeing of piece goods with the vat dyestuffs. By this special method cotton fabrics dyed with the vat colors m a y be manufactured a t the lowest cost, and in the greatest volume. When we cast up the account as rendered by the American dyer, we must be convinced that he has made a particularly good showing in this particular branch of his industry. With intelligent coaperation between the Government, the dyer, and the manufacturer, we can have a n army clothed with the strongest, best-wearing, and warmest uniforms in the world. May this result be attained! NEWYORKCITY
THE STATUS OF CHEMICAL ENGINEERING IN OUR UNIVERSITIES AND COLLEGES IMMEDIATELY PRIOR TO THE DECLARATION OF WAR B y HARPERF. ZOLLER~ Received May 3, 1918
It was while I was engaged in gathering data on a certain problem connected with curriculum work that I forwarded. the following questionnaire to the departments of chemistry in the various universities and colleges. The questionnaire was mailect on February 5 , 1917, and by March 21, 1917, all replies that were forthcoming had been received. In respect to the nature of the questionnaire and the replies, several have suggested to me that they should be tabulated and published, since they reflect the probable status of the chemical engineering courses in our schools a t the time the United States declared war. The replies have, therefore, been arranged in a table as far as their nature would permit. I take this opportunity to express my appreciation of the readiness on the part of those in charge of the departments of chemistry to cooperate by answering the questionnaire. Of the total number sent out, only one failed to answer and I attribute that instance to the inexactness of the third question. A few colleges have been included in the table to which the questionnaire were not sent. These are indicated. The data concerning these was secured from Volume I1 of the Report of the Commissioner of Education. A bulletin or catalogue of the courses in chemistry was also requested of each of the schools and received. QUESTIONNAIRE
I-Do you offer a cQurse in chemical engineering? 2-In what year was the course first offered? 3-Do you lay special emphasis on the course? 1 Formerly of the department of chemistry of the Kansas State Agri-cultural College, Manhattan, Kansas.
