of anthracene, caustic soda, potassium chlorate and
bichromate, and calling into existence the manufacture of fuming
sulphuric acid.

1870. Gallein, the first of the phthaleins, discovered by A. v. Baeyer,
followed in 1871 by coerulein, and in 1874 by the eosin dyes
(Caro). These discoveries necessitated the manufacture of phthalic
acid and resorcinol.

1873. Orthochromatic photography discovered by Vogel.

1876. Azo-dyes from the naphthols introduced by Roussin and Poirrier and
Witt, leading to the manufacture of the naphthols, sulphanilic
acid, &c.

1877. Preparation of quinone from aniline by Nietzki, utilized in
photography in 1880 for manufacture of hydroquinone.

1878. Disulpho-acids of beta-naphthol introduced by Meister, Lucius, and
Bruening, leading to azo-dyes from aniline, toluidine, xylidine,
and cumidine.

1879. Acid naphthol yellow introduced by Caro.

" Biebrich scarlet, the first secondary azo-colour, introduced by
Nietzki.

" Nitroso-sulpho acid of beta-naphthol discovered by the writer;
followed in 1883 by naphthol green (O. Hoffmann), and in 1889 by
eikonogen (Andresen).

" Beta-naphthol violet, the first of the oxazines, discovered by the
writer; followed in 1881 by gallocyanin.

" Coal-tar saccharin discovered by Fahlberg; manufacture made
practicable in 1884.

1880. Synthesis of indigo by A. v. Baeyer.

" Quinoline synthesised by Skraup's process.

1881. Kairine introduced by O. Fischer, the first artificial febrifuge.

" Indophenol discovered by Koechlin and Witt.

" Azo-dyes from new sulpho-acid of beta-naphthol introduced by Bayer
& Co.

1883. Antipyrine introduced by L. Knorr, leading to manufacture of
phenylhydrazine.

1884. Congo red, the first secondary azo-colour from benzidine,
introduced by Boettiger. Beginning of manufacture of cotton
azo-dyes, and leading to the production of benzidine and tolidine
on a large scale.

1885. Secondary azo-dyes from benzidine and tolidine containing two
dissimilar amines, phenols, &c., introduced by Pfaff.

" Tartrazine discovered by Ziegler; manufacture of sulpho-acid of
phenylhydrazine and of dioxytartaric acid.

1885. Thiorubin introduced by Dahl & Co., leading to manufacture of