INK. 



This ingenious method saves a vast 

 quantity of labour usually bestowed in 

 copying letters, and besides prevents all 

 possibility of mistakes. 



Sometimes the ink of very old writings 

 is so much faded by time as to be illegi- 

 ble. Dr. Blagden (Philosophical Trans- 

 actions, vol. Ixxvii. ) in his experiments 

 on this subject, found that in most of these 

 the colour might be restored, or rather 

 a new body of colour given, by pencilling 

 them over with a solution of prussiate of 

 potash, and then with a dilute acid, either 

 sulphuric or muriatic : or else, vice versa, 

 first with the acid, and then with the 

 prussiate. The acid dissolves the oxide 

 of iron of the faded ink, and the prussiate 

 precipitates it again of a blue, which re- 

 stores the legibility of the writing. If this 

 be done neatly, and blotting paper laid 

 over the letters as fast as they become vi- 

 sible, their form will be retained very 

 distinctly. Pencilling over the letters 

 with an infusion of galls also restores the 

 blackness to a certain degree, but not so 

 speedily nor so completely. 



The blackness of common ink is almost 

 instantly and irrevocably destroyed by 

 the oxymuriatic acid, and hence any 

 writing may be effaced by this method 

 completely. To prevent this mischief, 

 which might often be a serious one, se- 

 veral additions have been proposed to 

 common ink, of which by far the best is 

 lamp-black or charcoal, in impalpable 

 powder, on which the acid has no effect. 

 The lamp-black should be of the least 

 oily kind, as it does not readily mix with 

 the ink, and some pains must be taken to 

 incorporate them. On this account, per- 

 haps, common charcoal is preferable. 

 About a quarter of the weight of the vi- 

 triol used will be amply sufficient. This 

 will not fade by age. 



INK, China or Indian. The well known 

 and much admired Indian or China ink 

 is brought over in small oblong cakes, 

 which readily become diffused in water 

 by rubbing, and the blackness remains 

 suspended in it for a considerable time, 

 owing to the extreme subtlety of division 

 of the substance that gives the colour, and 

 the intimacy with which it is united to 

 the mucilaginous matter that keeps it 

 suspended. 



Indian ink does, however, deposit the 

 whole of its colour by standing, when it is 

 diffused in a considerable quantity, of wa- 

 ter. Dr. Lewis, on e? . nining this sub- 

 stance, found that the ink consisted of a 

 black sediment, totally insoluble in water, 

 which appeared to be of the nature of 

 the finest lamp-black, and of another 



substance soluble hi water, and which 

 putrified by keeping, and when evaporat- 

 ed left a tenacious jelly exactly like glue 

 or isinglass. It appears probable, there- 

 fore, that it consists of nothing more than 

 these two ingredients, and probably may 

 be imitated with perfect accuracy by 

 using a very fine jelly, like isinglass or 

 size, and the finest lamp-black, and in- 

 corporating them thoroughly. The finest 

 lamp-black known is made from ivory 

 shavings, and thence called ivory-black. 



INK, Printers'. This is a very singular 

 composition, partaking much of the na- 

 ture of an oil varnish, but differing from 

 it in the quality of adhering firmly to 

 moistened paper, and in being, to a consi- 

 derable degree, soluble in soap- water. 



It is, when used by the printers, of the 

 consistence of rather thin jelly, so that it 

 may be smeared over the types readily 

 and thinly, when applied by leather 

 cushions, and it dries very speedily on. 

 the paper without running through to the 

 other side, or passing the limits of the 

 letter. 



The method of making printers' ink is 

 thus described by Dr. Lewis. Ten or 

 twelve gallons of nut-oil are set over the 

 fire in a large iron pot, and brought to 

 boil. It is then stirred with an iron ladle, 

 and, whilst boiling, the inflammable va- 

 pour rising from it either takes fire of it- 

 self, or is kindled, and suffered to burn in 

 this way for about half an hour, the pot 

 being partially covered so as to regulate 

 the body of the flame, and consequently 

 the heat communicated to the oil. It is 

 frequently stirred during this time, that 

 the whole may be heated equally, other- 

 wise a part would be charred and the rest 

 left imperfect. The flame is then extin- 

 guished by entirely covering the pot. 

 The oil by this process has much of its 

 unctuous quality destroyed, and when 

 cold is of the consistence of soft turpen- 

 tine, and is then called varnish. After 

 this it is made into ink by mixture with 

 the requisite quantity of lamp- black, of 

 which about two ounces and a half are 

 sufficient for sixteen ounces of the pre- 

 pared oil. The oil loses by the boiling 

 about an eighth of its weight, and emits 

 very offensive fumes. Several other addi- 

 tions are made to the oil during the boil- 

 ing, such as crusts of bread, onions, and 

 sometimes turpentine. These are kept 

 secret by the preparers. The intention 

 of them is more effectually to destroy 

 part of the unctuous quality of the oil, to 

 give it more body, to enable it to adhere 

 better to the weUed paper, and to spread 

 on the types neatly and uniformly. 



