"Ten parts of logwood are to be exhausted with eighty of boiling water. To the solution one thousandth of its weight of yellow chromate of potash is to be added gradually. The liquid turns brown and at last blue-black. No gum is needed, and the ink is not removed by soaking in water. --Chemical Gazette, London (1850)." * * * * * * * * "Shellac, 2 oz.; borax, 1 oz.; distilled or rain water, 18 oz. Boil the whole in a closely covered tin vessel, stirring it occasionally with a glass rod until the mixture has become homogeneous; filter when cold, and mix the fluid solution with an ounce of mucilage or gum arabic prepared by dissolving 1 oz. of gum in 2 oz. of water, and add pulverized indigo and lampblack ad libitum. Boil the whole again in a covered vessel, and stir the fluid well to effect the complete solution and admixture of the gum arabic. Stir it occasionally while it is cooling; and after it has remained undisturbed for two or three hours, that the excess of indigo and lamp- black may subside, bottle it for use. The above ink for documentary purposes is invaluable, being under all ordinary circumstances, indestructible. It is also particularly well adapted for the use of the laboratory. Five drops of creosote added to a pint of ordinary ink will effectually prevent its becoming mouldy." * * * * * * * * "In November, 1854, Mr. Grace Calvert read a paper before the London Society of Arts in which he said that he hoped before long some valuable dyeing substances other than carbo-azotic acid would be prepared from coal tar. "In another paper read before the same society in 1858 he said: 'This expectation has now been fulfilled. Messrs. Perkins and Church have obtained several blue coloring substances from the alkaloids of coal tar, and one from naphthalene.' Also that himself and Mr. Charles Lowe had succeeded in obtaining coal tar products yielding colors of a beautiful pink, red, violet, purple, and chocolate. (These were not soluble in water)." * * * * * * * * "Among vegetable substances useful in the arts is one that has long been known in New Grenada under the name of the ink-plant, as furnishing a juice which can be used in writing without previous preparation. Characters traced with this substance have a reddish color at first, which turns to a deep black in a few hours. This juice is said to be really less liable to thicken than ordinary ink, and not to corrode steel pens. It resists the action of water, and is practically indelible. The plant is known as coryaria thymifolia." * * * * * * * * "Desormeaux recommends that the sulphate of iron be calcined to whiteness; coarse brown sugar instead of sugar candy; 1/4 oz. acetate of copper, instead of one ounce of the sulphate, and a drop or two of creosote or essential oil of cloves to prevent moulding." (See Ribaucourt receipt, p. 194.) * * * * * * * *