The practical utility of logwood as the base for an ink was a discovery of Runge in 1848, who found that a dilute solution of its coloring matter, to which had been added a small quantity of neutral chromate of potassium, produced a deep black liquid which apparently remained clear and did not deposit any sediment. This composition became very popular on account of its cheapness and dark purple color. It is of a fugitive character, though, and has passed almost entirely out of commercial use. CHAPTER XXI. ANCIENT AND MODERN INK RECEIPTS. "INDIAN" INK--SPANISH LICORICE--BITUMEN--CARBON FROM PETROLEUM--PROCESS TO OBTAIN GALLIC ACID--EFFECT OF SUGAR IN INK--DARK COLORED GALLS BEST FOR INK MAKING--SUBSTITUTES FOR GALLS--RELATIVE PROPORTIONS OF IRON AND GALLS--ANECDOTE OF PROFESSOR TRIALL-- ESTIMATION OF SULPHATE OF COPPER--QUAINT INK RECIPE--RIBAUCOURT'S INK--HORSELEY'S INK-- ELSNER'S INDELIBLE MARKING INK--BLACK INK FOR COMMON AND COPYING USES--COMMON BLACK INK--SHINING BLACK INK--PROCESS FOR "BEST" INK--INDELIBLE BLACK INK WITHOUT GALLS OR IRON--INK POWDER--STEEL PEN INK--SOME EARLY LITERATURE OF THE COAL TAR PRODUCTS--INK PLANT OF NEW GRANADA--"IMPERISHABLE" INK--FIRE- PROOF INK--"INERADICABLE" INK--EXCHEQUER INK--"PERMANENT" RED INK--SUBSTITUTE FOR "INDIAN" INK--TO PREVENT INK FREEZING--BACTERIA IN INK--GOLD AND OTHER INKS USED FOR ILLUMlNATING. INNUMERABLE receipts and directions for making inks of every kind, color and quality are to be found distributed in books more or less devoted to such subjects, in the encyclopaedias, chemistries, and other scientific publications. If assembled together they would occupy hundreds of pages. Those cited are exemplars indicating the trend of ideas belonging to different nations, epochs, and the diversity of materials. They can also be considered as object lessons which conclusively demonstrate the dissatisfaction always existing in respect to the constitution and modes of ink admixture. Many of them are curious and are reproduced without any amendments. "Indian ink is a black pigment brought hither from China, which on being rubbed with water, dissolves; and forms a substance resembling ink; but of a consistence extremely well adapted to the working with a pencil-brush, on which account it is not only much used as a black colour in miniature painting; but is the black now generally made use of for all smaller drawings in chiaro obscuro (or where the effect is to be produced from light and shade only). "The preparation of Indian ink, as well as of the other compositions used by the Chinese as paints, is not hitherto revealed on any good authority; but it appears clearly from experiments to be the coal of fish bones, or some other vegetable substance, mixed with isinglass size, or other size; and most probably, honey or sugar candy to prevent its cracking. A substance, therefore, much of the same nature, and applicable to the same purposes, may be formed in the following manner.