As compared with other industries, the value of the entire world-production of dyes is very slight, its worth in 1913, £20,000,000, not equalling a tenth part of the value of the wool crop, nor a fifth of the cotton crop, nor a third of the rubber crop. The dyes are, however, produced under very severe competition, and the finished products fetch a very high price. The energy, intelligence, and perseverance required for their manufacture are without parallel in any other industry.

The development of the dye industry has brought it about that many once carefully guarded secrets are now matters of general knowledge. Ullmann's great "Enzyklopaedie der Tech-nischen Chemie" has shown that many processes have long been known to most of the factories. Again, the migration of various workmen has made it inevitable that every important improvement becomes known to competitors in a relatively short time. The success of the great dye factories, therefore, is not founded on any secret processes, but upon the traditions of many years, upon excellent organization, and on the specialities which are protected by patents.

It is a great mistake to think that a colour works can be kept going indefinitely upon specialities alone, and not only do young inexperienced chemists fall into this error, but technical experts and business men frequently express this opinion. Specialities are, so to speak, the choice blooms in the garden of ordinary products, and it is necessary to prepare these commoner, everyday products side by side with the more profitable specialities. In order that a dye factory may be carried on on a big scale it is essential that the standard products should be made in the largest possible quantities. Such mass products or staple products are, first of all, black dyes such as Direct Deep Black EW, Chrome Blacks of various compositions such as Diamond Black PV, Alizarin Black, Erio Chrome Black T, etc.

Next in importance to the black dyes, which constitute over 50 % of the total, come the blue colouring matters, chiefly Indigo, Indanthrene, Direct Blue, and Sulphur Blue. After that come the red dyes such as Alizarin and Benzo Fast Scarlet; and finally, yellow products such as Chrysophenine and Naphthamine Yellow NN.

On the one hand these standard products give the salesman the opportunity of bringing his specialities to the notice of his customers, and, on the other hand, they tend to reduce the general overhead charges to a minimum. Emphasis has been laid already upon the importance of recovering all the by-products produced in the manufacture of intermediates, and it will be unnecessary to add more than a few words.

The various colour factories, recognizing this fact, have united together to form a so-called "Interessengemeinschaft," 1 the members of which sell their most important intermediate products to each other at the actual cost price, and, in addition, exchange information as to the methods of production. Owing to this concentration of effort it is possible to prepare each intermediate product on a very large scale, and to recover all by-products such as nitrous and sulphurous acids, hydrogen sulphide, thiosulphate, and Glauber salt, in the most rational way. As a necessary consequence of this it will be seen that such a community of interests must also manufacture their own inorganic intermediates in order that they may be independent as regards their supplies of caustic soda, sulphuric and hydrochloric acids, sodium carbonate and chlorine, and also common salt and coal if possible.

The plant used in a colour factory must be up-to-date, and the greatest mistake committed, which is indeed only too common, consists in continuing the use of badly working, out-of-date apparatus. It is often necessary to alter a plant at a day's notice in order to undertake some new manufacture, and it is the business of the superintendent to provide as suitable an apparatus as possible. It is far better to effect once and for all a complete and fundamental reconstruction of the plant than to use an unsatisfactory appliance which takes up a lot of room and requires many workmen to run it. It is nearly always found that in the long run a ruthless, even though costly, alteration is really the cheapest. The calculations are worked out by the Costing Department, which obtains the requisite data from the engineer and from the works chemist. In order that so complex a business as a dye factory shall run smoothly, it requires very careful organization. The actual management is always in the hands both of business men and chemists, who divide up matters between them into various departments, but who are always in direct

1 Literally = "Community of Interest," and is commonly referred to as the " I.G." contact upon all important questions. The commercial director deals with the purchase and sale of products, whilst the chemical directorate is responsible for running the works, the research laboratories and the dye-house. The so-called "Propaganda Dye-house "occupies a more or less intermediate position, and deals with such current business as advertising, the examination of new colours, whether of their own manufacture or made by competing firms, the preparation of pattern cards, and so on. The position of a chemist in a dye factory varies, therefore, very considerably according to whether he is engaged in the dye-house, in the research laboratories, in the works, in the patent department, and so on. The business of the research chemist consists in working out new scientific problems, keeping a careful eye on the technical literature. Too much emphasis cannot be laid upon the fact that it is quite useless to rush into the investigation of a problem until all the available information on the subject has been carefully examined. For this reason well-managed colour factories have a special department dealing with the literature of the subject which is able on request to furnish all details required from its carefully compiled indexes, thus making it possible to obtain quickly a complete summary of the existing information. It is frequently necessary to extend a given reaction over a wide field, and possibly to make hundreds of different dyes and preparations, as it is usually found that only quite a few of the compounds sought have any value (cf. Ehrlich-Hata "606"). If the Directorate, after consulting with the various departments, such as the dye-house, pharmaceutical laboratory, or other sections,. finds a new compound or process of sufficient interest, it is usually put through on a somewhat larger scale. This is carried out in the so-called Small-scale Plant, which is an intermediate link between the laboratory and the works. In this technical laboratory is found apparatus which is larger than that used in the research laboratories, but is, of course, far smaller than the actual works plant. In this way it is possible to get an idea as to how the reaction is likely to go on the large scale, thus frequently saving large sums of money.