Manufacture of India-Ink.

Manufacturer and builder 5, 1871

We communicated, on page 111, Vol. II., upon the authority of a London journal, the method said to be followed by time Chinese in making India ink. We suspect that time writer had been deceived by those who gave him the information. In any case, the account is meagre and defective. The material from which the lamp-black is prepared is not mentioned, and this is of the utmost importance. Only time coarser kinds of India ink are made from ordinary lamp-black; for the superior kinds, coal is obtained by burning, in an appropriate furnace, in iron or earthmen cylinders, cork, young sprouts of vines, or the stones of peaches, apricots, cherries, and other fruit, etc., in the same manner as bone-black is made. In using lamp-black, sifting is not sufficient to make it a fit material, as it is always fatty or oily, and this must be remedied by heating it over a fire in an iron or earthen vessel to such a degree that a few sheets of blotting-paper, placed on time top of time black, take fire. When well heated, and deprived of all greasiness, it is removed from the fire, covered up, and cooled, and then rubbed with water, gum-arabic, and sometimes a little sugar, to a paste, which is moulded in forms, and dried in the air. Time coal obtained by burning cork, vine-sprouts, peach-kernels, etc., must be reduced to an impalpable powder in a covered mortar, and passed throughia fine hair-sieve; then well rubbed wills rain-water and gum-arabic, with a very little musk to per-fume it. It is then placed in a water-bath and evaporated to the right consistency, to be formed into the usual sticks. If time Chinese really suppose that glue obtained from the horns of deer is the test for this purpose, it is only a notion of theirs, without foundation. This is not only no better than other good glue, but glue is not adapted for snaking India ink, since it cracks and shrinks in drying, as gum-arabic does not, and it does not easily dissolve in cold water, as gum-arabic does. India ink, made entirely with glue in place of gum-arabic, is decidedly objectionable, being too hard. Again, the statement that when time ingredients have been rubbed too much, time ink is spoiled, and that "the error is rectified by holding it before a slow fire," is absurd; the more time material is rubbed up, and time more finely it is pulverized, the more homogeneous will be the resultant mass, and the better the ink.

Artists in water-colors know that there are two shades of India ink, the brown and time blue, which can only be distinguished by comparison of the lighter tints produced with each. Of course, this difference depends upon the material from which time black has been de'rived; but a bluish shade is also produced by the addition of indigo. If this is added in the right quantity to a brown ink, a deep black is the result, producing perfectly neutral tints in the half-shadows. Such ink is, however, rare. The following prescription is claimed to give such a deep black ink; we have found it to be bluish; but by diminishing time amount of indigo, no doubt the neutral tint may be reached Take 8 parts well-burnt lamp-black, 64 parts water, 4 parts fine pulverized indigo, well rubbed up and boiled till the greater portion of time water is evaporated; then add 5 parts gum-arabic, 2 parts bone,- glue, 1 part extract of succory; boil till time mixture is as thick as paste, then mould in wooden forms, well greased with olive or almond-oil, in order to prevent adhesion. By using burnt peach-kernels or cork, in place of ordinary lamp-black, a finer quality may be given to time ink. The glue would better be left out, and gum-arabic substituted.

Many substances are used nowadays for the basis of black paints or India inks; as, for instance, the black soot obtained in chemical laboratories where coal-tar is treated for the manufacture of carbolic acid, aniline, etc., the deposit of a common oil lamp, or ke-rosene burner, or that of burning camphor with defi-cient access of air. In the latter case, however, the product (which is called Spanish black) must be washed with alcohol, to remove remnants of the original matter. The coal produced by burning time deposits obtained in making wine (called Frankfort black) may likewise be used in time preparation of India ink. But time most original of all is the method of Boszwell, who separates carbon without burning time mass containing it. He takes horn-shavings from button-factories, where they may be obtained in any quantity, and dissolves them in a solution of caustic potassa till time latter is saturated -that is, will dissolve no more. The dark-brown liquid is then eva-porated, in an iron vessel, to the consistency of a dough. This is again dissolved in twice its volume of boiling water, and a solution of alum is added, which precipitates the carbon in a condition finer than time finest pulverization can make it. Time deposit is washed, dried, and simply mixed with gum-water. As time carbon is thus at once obtained in time wet condition, the process of mixing lamp-black with water is avoid. ed. In time ordinary manufacture, this is a tedious manipulation, since time black floats on water and refuses to mix with it. It is true, the addition of a little alcohol facilitates matters; but timis causes an additional expense, of some importance when large quantities are treated.