Coloring Power of Aniline Dyes.

Manufacturer and builder 2, 1871

One of the most striking instances of the great divisibility of matter is shown by the power of the aniline dye when separated into infinitesimal particles. According to Hoffman, one part of fuchsine or aniline red, when dissolved in one million parts of water, will give a deep crimson hue to the entire solution; and a bunde of silk, slightly moistened with acetic acid, on being immersed therein, will be instantly dyed a beautiful red.

If twenty-five million parts of water to one of aniline red be used, the red tinge still remains quite visible, and a light shade will be imparted to silk by it in about fifteen minutes; but if the amount of water be increased to one hundred million parts, the solution will be apparently colorless.

A slight trace of color may, however, be detected by looking through thick portions of the liquid, partly by transmitted and partly by reflected light; and a white silk thread immersed therein will become distinctly but unevenly colored within twenty-four hours.

The fact of the tints on the thread being in some places of a darker shade than the liquid itself, seems to prove that under the placid exterior of the solution currents exist, which carry the molecules of color to the thread, and distribute them unevenly on its surface.