Scientific American 26, 8.3.1856
(For the Scientific American.)
Messes. Editors - In your paper of the 2d of February you state "that Piesse Dupierre, of Paris, has obtained a patent for the employment of alder flowers to form a substitute for cream of tartar in dyeing black and other colors."
That alder flowers and the bark of alder are valuable materials in dyeing black is nothing new, for between the years 1796 to 1805 I used many tuns of them in black dyeing. When a supply could not be obtained I used white oak saw-dust, which I found to produce a still better effect. Any material containing gallic acid and tanning principle can be used to advantage in black dyeing. In this country, during the last English war, I used our swamp maple bark with better effect than alder. Three pounds of ground maple bark s equal to one pound of nut-gall.
Cream of tartar is used in a given range of bright colors, such as scarlet, orange, aurora, yellows, crimson, purple, violet, &c., for the purpose of imparting to them great brilliancy. It is used with either muriate or nitro-muriate of tin. The nitric and muriatic acids having a greater affinity for potash then the tartaric combines with it, liberates the tartaric acid, which combines with tin, forming in the liquor a tartrite of tin, which gives great brilliancy to coloring matters. How the gallic acid and tanning principle, both possessing powerful saddening qualities, and precipitating tin instead of combining with it, can be used in place of the tartaric, is to me very unaccountable. It is well known by experienced dyers that cream of tartar is never used in black dyeing, as it operates as a check on saddening. Both the gallic and tartaric acids are triple compounds of the same elements, hydrogen, carbon, and oxygen, but varying materially in their proportions, tartaric containing forty per cent. less hydrogen, twenty less carbon, and sixty per cent. more oxygen. Perhaps M. Pierre Dupierre may have some cheap magic process by which he can change the components of the gallic into the tartaric.
Binghamton, N. Y., Feb. 18, 1856.