Plan No. 473. Blue Ink Powder
Many people prefer blue ink, and for them he made powders of an excellent quality as follows:
Water-blue anilin, 1 dram; dextrin, 5 drams; or according to the following formula:
Soluble Prussian blue, 1 dram; dextrin, 2 drams. Dissolve the powder in hot water, varying the intensity of the blue shade as desired, by using more or less powder.
This was a popular and profitable seller.