Scientific American 23, 8.6.1861
In a late number of Comptea Rendus a new color, called Paris Blue, is described. It states that 0 grammes of the bichloride of tin and 16 grammes of aniline, heated for 30 hours in a sealed tube at 180°, yield a very bright and pure blue color, which requires only to be treated with water to dye animal fibers beautiful bright tints. This blue resists acids; is deepened in tone with feeble alkalies, but becomes a purple with concentrated alkalies. This is a most important discovery, and is another addition to the remarkable series of rich colors derived from the products of coal tar. We would not be much surprised if all the colors and shades of colors - reds, blues, yellows, drabs, &c. - were yet to be produced on textile fabrics by the products obtained from our oil wells and coal mines. This new blue dye is also called azuline, and is now manufactured and sold in Paris and London in the same manner as Magenta coloring matter.