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DYEING
871


United States 3-3, Austria 1-6, Russia i-i. In view of the great changes which have taken place these figures are now of course no longer valid. What the figures were in 1921 was not even ap- proximately known, but it is certain that the world's producing capacity, as dis'tinct from actual production, was far in excess of any likely demand.

A good deal has been said and written about the correlation of dyestuff manufacture and the manufacture of high explosives, poison gases and other products required for chemical warfare. As far as the manufacture of high explosives is concerned, two main products, namely picric acid and trinitro toluole (T.N.T.), come into consideration. It is not very generally known that the former was made in England in large quantities as a dyestuff long before the French introduced it as an explosive. As a dye- stuff it has long since been discarded, having been replaced by other coal-tar yellows of greater fastness which are not subject to any official restrictions. Both of these substances are nitro compounds of the aromatic series, and, like those manufactured as intermediates for dye-making, require, besides the coal tar common to both, large quantities of sulphuric acid, oleum and nitric acid (all products of the so-called " heavy chemical " industry) as raw materials. The nitrating operations are similar in both cases and similar plant is used, but there is always a limit to the size of the nitrating vessels which it is neither safe nor economical to exceed. Once the process is standardized on a unit of plant any increased production is obtained by increasing the number of units. Naturally any plant producing such nitro compounds in a colour works could in an emergency be turned to account to produce such a substance asT.N.T.,but the amounts required for any serious military or naval operations would be vastly in excess of what could be turned out with the nitration plants of even large colour works. Nitrating is only one of a large number of important operations required in colour manu- facture, and some dyestuffs are manufactured entirely without the help of this operation. The idea which seems to have become prevalent that the plant in a colour works is capable of turning out anything from a finished dyestuff to mustard gas or any new product that may come along is untenable. What is really wanted in this respect is a body of alert, scientifically and technically trained chemists. The best guarantee for the re- quirements of " chemical warfare " in the future is the possession of a successful colour industry, for the chemist best suited by training and habit of mind to cope with an emergency problem is the colour chemist.

REFERENCES. J. K. Wood, The Chemistry of Dyeing (1913); J. Merritt Matthews, Application of Dyestuffs; C. M. Whittaker, The Application of the Coal-Tar Dyestuffs (1919) ; A_. G. Green, Analy- sis of Dyes and Dyed Materials (1911) ; for qualitative and for quanti- tative work, New Reduction Methods in Volumetric Analysis, Knecht and Hibbert. (E. K.)

United States. The dyeing industry of the United States during 1910-21 grew commensurately with the textile industries. An important advance was made in the production of fast colours on cotton goods. This was in keeping with the rapidly extended use of cotton in high-grade wearing apparel and the increase of steam laundries, displacing household washing. Modern laundry methods of rapidly cleansing and whitening fabrics necessitated the use of strong chemicals, destructive of the colours formerly employed in dyeing cotton. The demand for laundry -fast colours was met by the introduction of the so-called " vat " dyes of which indigo was long the only representative. The extended use of the dye known as sulphur black to take the place of aniline black for cotton hosiery and piece-goods was also worthy of note. The silk industry in America also grew largely, consuming more raw silk in manufactures than any other country. This led to the great extension of silk-dyeing, chiefly in the industrial centres of South Manchester, Conn., Paterson, N.J., and Lancaster, Pa.

The World War at first threw the dyeing industry in the United States into confusion, owing to the uncertainty of trade relations with Germany, the more so when the Allied blockade put a complete embargo on Germany's exports. It was then seen how dependent America had been on Germany for dye-

stuffs, and it was estimated that manufacturing industries with products valued at about $4,000,000,000 might soon be thrown completely out of gear by a lack of dyestuffs. In the confusion which resulted all manner of expedients were adopted in the production of colours with a consequent reduction in the fastness and quality of dyeing. Dyestuffs became so scarce that exorbi- tant prices stimulated the erection of many dyestuff factories in various parts of the United States. Large amounts of capital were freely invested in the new industry, and many chemists became engaged in dyestuff research and manufacturing.

Previous to the war the United States had a small dyestuff industry distributed among about five plants. The manufactur- ing operations, however, were limited chiefly to the assembling of the coal-tar intermediates imported from Germany for the production of the finished dyes, so that the new industry had to be built from the ground up. To the great credit of the American chemist and chemical manufacturer it may be said that in a very short time the more important dyes were successfully made in the United States in such quantity that practically no dye-con- suming industry was forced to shut down by reason of a lack of dyes. Indigo and sulphur black wore soon produced on a large scale, as well as the required acid dyes for wool and silk, most of the basic dyes, and a complete line of the direct cotton dyes. In 1920 there were 213 firms manufacturing dyestuffs and related coal-tar chemicals. These employed about 2,600 chem- ists and nearly 20,000 workmen and the total value of the finished products amounted to over $112,000,000. There were 236 different intermediates manufactured, and 360 different dyes. The total production of dyes amounted to over 88,000,000 Ib. as against a pre-war importation of about 70,000,000 pounds. The total value of the finished dyes was given as $95,600,000, so that the average price per pound was about $1.07. Over 18,000,000 Ib. of synthetic indigo was made, about twice the pre-war importation, indicating great extension in the use of indigo. Associated with the making of dyestuffs there also grew up the many related branches of the coal-tar chemical industry, such as colour lakes for paints, lithographic and print- ing inks; coal-tar Pharmaceuticals; flavouring and perfume materials; photographic chemicals and synthetic tannins and resins. The great growth of the industry created a constant demand for increasing quantities of coal-tar distillates, which form the raw materials of the dyestuff industry, and this led to a rapid increase in the number of by-products coke ovens. In 1920 the production of coke in by-product ovens amounted to about 60 % of the total.

The great production of dyes in the United States during the period 1917-21 led to the building up of a considerable export trade, particularly to South America and the Orient. The total dyestuffs exported from the United States in 1920 amounted in value to nearly $30,000,000, of which $22,450,000 was for coal-tar dyes. This export trade, however, showed a rapid falling off from the beginning of 1921, due both to the general business depression throughout the world and to the fact that the German dyestuff manufacturers were again active in foreign trade.

At the close of the war the American dyestuff manufacturers quickly realized that unless they had suitable Government pro- tection they could not meet aggressive competition from Euro- pean dyestuff factories. In 1916 they petitioned for, and obtained the passage of, a bill placing a tariff of 30 % ad valorem and a specific duty of 5 cents per pound on most dyes. When hostilities ended certain Government regulations were also applied to the importation of dyestuffs and related products from Germany so that such importations were licensed to bona fide consumers and were limited to dyes that could not be satisfactorily obtained from the American manufacturers. In the meantime Congress was petitioned for an embargo on importation of dyes from foreign sources except under adequate licence regulations which would restrict the imports to dyes not manufactured in the United States. This was in line with similar action by Great Britain, France, Italy and Japan, all these countries deeming it highly expedient to foster and build up a self-contained dyestuff and coal-tar chemical industry as a measure of national defence.