21,199. Newton, P. A., [Farbenfabriken vorm. F. Bayer & Co.]. Sept. 12. Disazo dyes are obtained by combining the tetrazo compound of p-p<1>-diaminodiphenyluream-m<1>-disulphonic acid in acid or neutral solution with one molecular proportion of 2-amino-8- naphthol-6-sulphonic acid or its alkyl, aralkyl, or aryl derivatives, and in the usual way with one molecular proportion of a 2-naphthylamine sulphonic acid or an alkyl or aralkyl derivative thereof, or in alkaline solution with one molecular proportion of an alkyl, aralkyl, or aryl derivative of 2-amino-5-naphthol-7-sulphonic acid; or by combining the above tetrazo compound with two molecular proportions of the same or different 2-naphthylamine sulphonic acids or their alkyl derivatives; the combinations can be effected in any order. The same dyes are obtained by treating with phosgene two molecular proportions of the alkali salts of the monoazo dyes obtained by combining the diazo compounds of p-nitraniline-o-sulphonic acid or p-acetylaminoaniline-o-sulphonic acid with a 2-naphthylamine sulphonic acid or an alkyl derivative thereof and reducing or saponifying the products, or by treating with phosgene two molecular properties of different monoazo dyes obtained as above from 2-amino-8-naphthol- 6-snlphonic acid or its alkyl, aralkyl, or aryl derivatives, 2-naphthylamine sulphonic acids or their alkyl derivatives, or alkyl, aralkyl, or aryl derivatives of 2-amino-5-naphthol-7-sulphonic acid. According to examples, dyes are obtained from the above tetrazo body and (1) two molecular proportions of 2-methylaminonaphthalene- 7-sulphonic acid, (2) one molecular proportion of 2:8:6-acid and one molecular proportion of 2-methylaminonaphthalene-7-sulphonic acid, (3) one molecular proportion of 2:8:6-acid and one molecular proportion of 2-phenylamino-5-naphthol-7-sulphonic acid. Ethyl and benzyl derivatives of 2-naphthylamine sulphonic acids, or of 2:8:6- or 2:5:7-acid are also specified as components. The production of the dye described under (1) above by treating the corresponding monoazo dye with phosgene is also given in an example. The products dye cotton red to violet-red shades. Specification 11,766/01 is referred to. The Provisional Specification refers also to the production of disazo dyes from the above tetrazo compound and two molecular proportions of 2-naphthylamine or its derivatives or one molecular proportion of one of these and one molecular proportion of any other component. Trisazo dyes.-The Provisional Specification also refers to trisazo dyes obtained from the above tetrazo compound with one molecule of 2-naphthylamine or its derivatives and one molecule of an azo dye capable of combining with diazo compounds ; according to examples the following components are used: (1) 2- methylnaphthylamine and the chrysoidine from o-sulphanilic acid and m-phenylenediamine; (2) 2:8:6-acid and the monoazo dye obtained in acid solution from aniline and 2:5:7-acid. These products also dye cotton. 2-Methylaminonaphthalene-7-sulphonic acid is obtained by treating 2-naphthol-7-sulphonic acid with methylamine in presence of bisulphite. 2-Ethylaminonaphthalene sulphonic acids are obtained similarly from 2-naphthol sulphonic acids and ethylamine. 2-Benzylaminonaphthalene sulphonic acids are obtained from 2-naphthylamine sulphonic acids and benzyl chloride.