Experiments on the fading of colors.

Manufacturer and builder 7, 1876

—It has been observed by Kœchlin that woolen cloth dyed with indigo had its peculiar blue color notably diminished by being exposed to a freezing temperature. According to some experiments made by Goppelsrader, this discolorization is data to ozone present, which acts at temperatures below zero, but only when the tissue was wet. Cochineal reds on wool seem to lose their brilliancy when exposed to the action of ozone for eight days. Anilin black was unchanged, but anilin brown on cottons was turned into a yellowish brown. Magenta, anilin blues and violets, and iodin greens were unchanged, as were lakes and strong colors as Turkey red. Ozone seems, however, to have in some instances the property of developing and intensifying certain colors, more especially the anilin blacks.