of the ancients was characterized by great permanency, being composed of finely pulverized carbon mixed with a mucilaginous or adhesive liquid. India or China Ink is of this composition: it is formed of lamp-black and size or fine animal glue, with the incidental addition of perfumes. It is used in China with a brush, both for writing and painting on Chinese paper; and it is employed in other countries for making drawings in black and white,—the different depths of shade being produced by varying the degree of dilution in water.
Inks of other colors than black were anciently used only for purposes of ornamental and decorative writing. In later and present times, red and blue inks have been extensively employed in ruling account-books and other paper for like uses. Blue ink, within ten or more years past, has been, with many, a preferred fluid for common writing.
Blue ink, when properly made, flows with great ease and rapidity from the pen, dries almost instantly on the paper, and has been supposed or expected to be quite durable, and unchangeable in color, under ordinary vicissitudes. Yet, experience has demonstrated the contrary,—though various and well-contrived chemical combinations have been attempted for the purpose. Blue inks that change to black some time after writing
