INK 915 



a solution of oxalic acid. The blue should be washed in dilute muriatic acid. M. 

 Harnung has given the following as the best formula for blue ink : 



Mix 4 parts of perchloride of iron in solution with 750 parts of water, then add 

 4 parts of cyanide of potassium dissolved in a little water ; collect the precipitate 

 formed, wash it with several additions of water, allow it to drain until it weighs about 

 200 parts ; add to this one part of oxalic acid, and promote solution of the cyanide 

 by shaking the bottle containing the mixture. The addition of gum and sugar is 

 useless, and even appears to exercise a prejudicial effect on the beauty of the ink. It 

 may be kept without any addition for a long time. 



Gold and Silver Inks are prepared by grinding upon a porphyry slab, with a muller, 

 gold or silver leaves, with white honey, until they are reduced to the finest possible 

 state of division. The honey is thoroughly washed from the powdered metals, and 

 these are mixed up with gum-water. 



Indelible Ink. A very good ink, capable of resisting chlorine, oxalic acid, and ab- 

 lution with a hair-pencil or sponge, may be made by mixing some of the ink made by 

 the preceding prescription, with a little genuine China ink. It writes well. Many 

 other formulae have been given for indelible inks, but they are all inferior in simplicity 

 and usefulness to the one now prescribed. Solution of nitrate of silver thickened with 

 gum, and written with upon linen or cotton cloth, previously imbued with a solution 

 of soda, and dried, is the ordinary permanent ink of the shops. Before the cloths are 

 washed the writing should be exposed to the sunbeam, or to bright daylight, which 

 blackens and fixes the oxide of silver. It is easily discharged by chlorine and ammonia. 



A good permanent ink may be made by mixing a strong solution of chloride of 

 platinum with a little potash, sugar, and gum to thicken. The writing made there- 

 with should be passed over with a hot smoothing iron to fix it. 



Another indelible ink may be prepared by adding lamp-black and indigo to a so- 

 lution of the gluten of wheat in acetic acid. This ink is of a beautiful black colour, 

 at the same time cheap, and cannot be removed by water, chlorine, or dilute acids. 

 M. Herberger gives the following directions for its preparation : Wheat gluten is 

 carefully freed from the starch, and then dissolved in a little weak acetic acid ; the 

 liquid is now mixed with so much rain-water that the solution has about the strength 

 of wine vinegar, that is, neutralises -j^th of its weight of carbonate of soda. 10 grains 

 of the best lamp-black and 2 grains of indigo are mixed with 4 ounces of the solution 

 of gluten, and a little oil of cloves added. This ink may be employed for marking 

 linen, as it does not resist mechanical force. 



Indelible ink of Dr. Traill is essentially the same as above. 



French indelible ink is made of Indian ink diffused through dilute muriatic acid 

 for writing with quills, and through weak potash-lyo for writing with steel pens. 



Marking Ink. The inks used for marking linen generally consist of a solution of 

 nitrate of silver, coloured with sap-green, Indian ink, or some other colouring agent, 

 and thickened with gum. Under the combined influence of light and the organic 

 matter, the salt of silver is decomposed, and a black stain is produced. This is in- 

 delible when washed with soap and water, but may be removed by a solution of 

 cyanide of potassium. 



A cheap indelible marking-ink, which resists the action of chlorine, and is employed 

 by bleachers to mark their goods, is prepared by dissolving coal-tar in naphtha. 



Ink-powders are occasionally used, but consist merely of the common constituents of 

 ink in a dry state. A black ink of this kind may be prepared by mixing 4 parts of 

 powdered gall-nuts with 2 parts of green copperas and 1 part of gum arabic. This 

 mixture may be conveniently carried in the form of a powder, and may be prepared 

 for use by simply dissolving it in water. 



China or Indian Ink. Proust says that lamp-black purified by potash-lye, when 

 mixed with a solution of glue and dried, formed an ink which was preferred by 

 artists to that of China. M. Merime'e, in his interesting treatise entitled De la 

 Peinture a I'Huile, says, that the Chinese do not use glue in the fabrication of their 

 ink ; but that they add vegetable juices, which render it more brilliant and more 

 indelible upon paper. When the best lamp-black is levigated with the purest gelatine 

 or solution of glue, it forms, no doubt, ink of a good colour, but wants the shining 

 fracture, and is not so permanent on paper as good China ink, and it stiffens in cold 

 weather into a tremulous jelly. Glue may be deprived of the gelatinising property 

 by boiling it for a long time, or subjecting it to a high heat in a Papin's digester ; 

 but as ammonia is apt to be generated in this way, M. Merimee recommends starch- 

 gum, made by sulphuric acid, to be used in preference to glue. He gives, however, 

 the following directions for preparing this ink with glue. Into a solution of glue he 

 pours a concentrated solution of gall-nuts, which occasions an elastic resinous-looking 

 precipitate. He washes this matter with hot water, and dissolves it in a spare 

 solution of clarified glue. He filters anew, and concentrates it to the proper degree 



