Discoveries And Inventions Abroad: Blue Aniline Dye.

Scientific American 9, 28.2.1863

J. Ingham and W. P. Wood, of England, manufacture a blue color from any red aniline dye, by mixing the latter with caustic soda and subjecting it to a high heat in a sealed tube. The red color is gradually converted into a blue solution by this treatment. To render it fit for coloring silk, wool and cotton, the blue color thus obtained is dissolved in alcohol.