aniline are, para-phenylene-diamine, dimethyl-para-phenylene-diamine, para-amido-diphenylamine, para-amido-phenol, etc.” This method may be used alone as the other Aniline Blacks, or the dyed skins may be after-dyed in a bath containing a logwood dye, or it may be used in conjunction with mineral dyes, or with the Oxidation Colors (see next chapter). A typical formula for the black by Green’s process is the following: Para-amido-phenol 0.5 kg. Aniline oil 10 liters Hydrochloric acid 22° Bé. 10 liters Acetic acid 40% 5 liters Cold water 25 liters This is solution A. Solution B is prepared by dissolving Copper sulphate 2 kg. Salammoniac 10 kg. Cold water 50 liters A and B are mixed, and the mixture applied to the hair of the furs several times, drying each time at 35°–40° C. After three coats of dye have been applied, a pretty and fairly intense black shade is obtained, which is developed further by treating with a solution of 25 grams of sodium bichromate per liter of water. The skins are then allowed to dry in air, and then if desired, an after-dyeing is made with some other dye. On account of its extreme fastness, Aniline Black, produced by any of the methods outlined above, has attained a justifiable popularity for the dyeing of furs, in spite of the necessity of using the more or less cumbersome brush method of applying the dye. Very recently there was issued to a German company a patent in which is described a method whereby furs can be dyed with Aniline Black by the dip process. An abstract of the patent (D. R. P. 33402) is as follows: “As is known, aniline salt, and similar salts, together with oxidizing agents like bichromates, chlorates, etc., cannot be used for dyeing furs by the dip process, because the strongly dissociated mineral acid is injurious to the leather. The dissociation of the acid can be reduced by adding neutral salts, like common salt, or Glauber’s salt, so that good results can be obtained by dyeing in a bath of the dye mixture, the leather retaining its softness.” Thus far there have been no reports of the successful practical application of this patent, so its value cannot be discussed. It is extremely doubtful, however, that furs will ever be dyed in the dyebath with the present type of Aniline Black formulas, no matter what substances are added to prevent the leather from being affected. CHAPTER XV FUR DYEING OXIDATION COLORS