3. Best, or Japan Ink.—M. Ribaucourt, who has paid particular attention to the process of making black ink, has drawn the following inferences from his experiments. That logwood, from its disposition to unite with the solutions of iron, is a valuable ingredient in the making of ink, rendering it not only of a very dark colour, but less capable of change from the action of acids or of the air. That sulphate of copper, in a certain proportion, gives depth and firmness to the colour of the ink. That gum has all the advantages we have before named. That sugar (although it has some bad qualities) is of use in giving a degree of fluidity to the ink, which permits the dose of gum to be enlarged beyond what the ink would bear without it. That water is the best solvent. From these considerations M. Ribaucourt has given the following directions for the composition of good ink, namely, 8 ounces Aleppo galls, 4 ounces logwood, 4 ounces sulphate of iron, 3 ounces gum arabic, 1 ounce sulphate of coppeil nd 1 ounce of sugar candy The villa logwood to be boiled in 12 lbs water, till reduced to 6 lbs. and after straining, the other ingredients are to qe added. This ink flows from the pen of a jet black, and from the gum being in greater proportion to the liquid than in the previous recipe, the writing dries with a gloss upon it ; hence it has been called Japan ink. If it is desired to give it more gloss, the gum may be increased, to which some more sugar must be added to give it equal fluidity ; but an excess in &Clatter ingredient render papers written upon with it liable to stick together, upon contracting the least dampness.
M. Desormeaux, jun. an ink manufacturer of Spitalfields, gave an excellent recipe for making ink some time since in the Philosophical Magazine ; but as his process does not differ essentially from those we have given, and as his observations are confirmatory, as far as they extend, of our own, we shall only notice the points of difference in his communication. He directs the sulphate of iron to be calcined to a whiteness, and employs comae brown sugar instead of sugar-candy, the acetate of copper instead of the sulphate, and only is one -fourth the quantity ; and recommends the ink to be agitated twice a day for a fortnight before it is poured from the dregs and corked up for use. These variations appear to be judicious and deserving of .imitation.
Dr. Lewis and others have recommended vinegar as the menstruum in pre ference to water; on which, as well as the sulphate of copper of Mr. Bibaucourt, Dr. Ure acutely observes, " I have found an inconvenience in the use of either, which, though it does not relate to the goodness of the ink, is sufficiently great, in their practical exhibition, to forbid their use: The acid of the vinegar acts so strongly upon the pen, that it very frequently requires mending; and the sulphate of copper has a still more unpleasant effect upon the pen-knife. It seldom happens that when a pen requires mending, that the ink IS wiped very perfectly from it; and often, when the nib is only to be taken off, it is done without wiping at all. Whenever this is the case, the ink immediately deposits a film of copper upon the knife, and by superior electric attraction of the sulphuric acid, a correspondent portion of the edge of the knife is dissolved, and is by this means rendered incapable of cutting until it has been again set upon the bone.
4. Copying Ink,—for transferring writings to thin unsizedpaper is prepared by the simple addition of a little sugar to common writing ink. The powerful affinity of water to sugar, causes the damp paper to immediately absord the ink by the powerful aid of the copying-machine. See COPYING PREYS.
5. Indelible Ink.—It is well known that common writing ink may be easily obliterated by the application of oxymuriatic acid, or aqueous chlorine; It therefore becomes an Important object to employ :those substances which 4011 be indestructible by the application of any process-that will not at the same time destroy the material upon which it shall be used. For this purpose Mr. Close has recommended twenty-five grains of copal in powder, dissolved in two hundred grains of oil of lavender, by the assistance of a gentle heat, and then mixed with two and a half grains of lamp-black, and half a grain of indigo. A little oil of lavender, or of turpentine, may be added if the ;ink be too thick. Mr. Sheldrake suggests that a mixture of genuine asphaltum, dis solved in oil of turpentine, amber varnish, and lamp-black, would be superior to the foregoing. For many common purposes the introduction of a little lamp black into the composition of common ink will answer sufficiently. In the Journal of the Royal Institution the following process of making an indelible ink has been recommended :—Let a saturated solution of indigo and madder in boiling water be made in such proportion as to give a purple tint ; add to it from one-sixth to one-eighth of its weight of sulphuric acid, according to the thickness and strength of the paper to be used. This makes an ink which flows pretty freel from the pen ; and when writing which has been executed with it is ex to a considerable but gradual heat from the fire, it becomes completely lack, the letters being thoroughly burnt in, and charred by the action of the sulphuric acid. If the acid has not been used in sufficient quantity to destroy the texture of the paper, and reduce it to the state of tinder, the colour may be discharged by the oxymuriatic and oxalic acids, and their com pounds, though not without great difficulty. When the full proportion of acid has been employed, a little crumpling and rubbing of the paper reduces the carbonaceous matter to powder; but by putting a black ground behind them they may be preserved; and thus a species of indelible writing ink is procured, (for the letters are in a manner stamped out of the paper) which might be useful for some purposes, perhaps for the signature of blank notes. (See the inks for marking linen.) When writing with common ink has been effaced by means of -aqueous chlorine, the vapour of sulphuret of ammonia, or immersion in water impregnated with this sulpburet, will render it again legible. Or if the paper that contained the writing be put into a weak solution of prussiate of potash, and when it is thoroughly wet, a little suphuric acid be added to the liquor, so as to render it slightly acidulous, the same purpose will be answered.