This work compiles a great number of formulas, and rather favors the views of the chemist Dr. Bostock respecting the iron and gall inks. The book possesses value for reference purposes to the manufacturer.
Auguste Peret, author of "The Manufacture of Ink," 1891, has put together a lot of excellent material relative to ink-making and valuable for reference purposes.
The late Dr. William E. Hagan of Troy, New York, in 1894 issued his book, "Disputed Hand-writing." He devotes two chapters to the discussion of ancient and modern inks and their chemistry. He has been kind enough to quote the writer as the first to remove ink in open court with chemicals in order to determine the existence of pencil writing beneath the ink. The pencil being carbon was not affected thereby and with the subsequent restoration of the bleached ink by the use of the correct re-agent.
In the same year Dr. Persifor Frazer of Philadelphia published his "Manual of the Study of Documents." A few pages are given to the study of inks, and a part thereof is devoted to the researches of Carre, Hager, Baudrimont, Tarry, Chevallier and Lassaigne, to determine suspected forgeries. The chapter on "the sequence in crossed lines," where he indicates his method of determining which of two crossed ink lines was written first, is both original and a real contribution to science.
Alfred H. Allen, F. C. S., of England, perhaps the highest authority on the subject of tannins, dyes and coloring matters in his "Commercial Organic Analysis," revised and edited by Professor J. Merritt Mathews of Pennsylvania, edition of 1900, devotes eight pages to the subject of the "Examination of Ink Marks." He says:
"Ordinary writing ink was formerly always made from a decoction of galls, to which green vitriol was added. Of late, the composition of writing inks has become far less constant, aniline and other dyes being frequently employed, and other metallic salts substituted for the ferrous- sulphate formerly invariably used. The best black ink is a tanno-gallate of iron, obtained by adding an infusion of nut-galls to a solution of ferrous- sulphate (copperas)."
In 1897 the author in a paper read before the New York State Bar Association at Albany, entitled "A Plea for the Preservation of the Public Records," discussed the question of the stability of inks and their phenomena and took occasion to make recommendations as to their constitution and future methods of employment. A vote of thanks was adopted and the association referred the paper to the Committee on Law Reform, where no doubt it still slumbers.