M. Grandsire has made the grand discovery (to dye indigo blue upon a bottom of aniline gray)

The Textile Mercury, 12.3.1892

M. Grandsire has made the grand discovery that it is profitable to dye indigo blue upon a bottom of aniline gray, and of course has obtained a French patent for the long known process, which is practised everywhere. He works 100 kilos. cotton for one hour upon a cold bath of 1,000 litres water, 2 kilos. aniline oil, 8 kilos. hydrochloric acid, and four kilos. chromate of soda or of potash; washes in two waters, centrifugates, and immediately enters the vat. Or he dyes only for ½ hour upon the cold bath, and raises the temperature during another half-hour to 60°, washes, and for the rest proceeds as above. In the former ease a verdigris colour is obtained, which after washing turns violet, and in the latter case a dark gray.