INK. 



law in the mean time, and therefore an 

 injunction is granted of course ; but this 

 injunction only stays execution touching 

 the matter in question, and there is al- 

 ways a clause giving liberty to call for a 

 plea to proceed to trial, and for want of 

 it to obtain judgment ; but execution is 

 stayed till answer, or farther order. The 

 methods of dissolving injunctions are va- 

 rious. 



INK, common -writing. The preparation 

 of common writing ink is a subject of 

 great importance in technical chemistry. 

 A good ink is of a proper consistence to 

 flow freely from the pen, of a full deep 

 black, so permanent as to remain for a 

 number of years without materially fad- 

 ing or becoming illegible, dries very soon 

 after writing with it, and does not consi- 

 derably corrode or soften the pen. The 

 basis of all the common writing inks is 

 the fine black, or dark blue precipitate, 

 formed by the addition of vegetable as- 

 tringents, and particularly the soluble 

 part of the gall-nut, to a solution of iron, 

 generally the sulphate. But as this, if 

 diffused in water alone, would subside in 

 a short time, and leave the supernatant 

 liquor nearly without colour, the precipi- 

 tate is kept suspended, by thickening the 

 water with gum arable, or any other gum 

 mucilage, which also gives the ink the 

 due consistence, and enables it to trace 

 a fine stroke on the paper, without run- 

 ning. These materials, therefore, that is, 

 gall-nuts, green vitriol, (sulphate of iron) 

 gum arable, and water, are all that are 

 necessary for the composition of ink ; 

 and if they are of good quality, and pro- 

 perly proportioned to each other, every 

 other addition usually made adds very 

 little to its perfection. 



It is not well ascertained how soon the 

 present kind of writing ink came into use. 

 It has certainly been employed for many 

 centuries in most European countries ; 

 but the ancient Roman inks were, for the 

 most part, of a totally different composi- 

 tion, being made of some vegetable car- 

 bonaceous matter like lamp-black diffus- 

 ed in a liquor. The Chinese, and many 

 of the inks used by the Oriental nations, 

 are still of this kind. 



On the subject of the common writing 

 ink, Dr. Lewis (" Commerce of Arts") 

 has so full and so accurate an investiga- 

 tion, and his experiments are so simple 

 and well devised, that little else can be 

 added to the subject in a technical point 

 of view. For a fuller chemical inquiry 

 into the nature of the atramentous preci- 

 pitate, the reader is referred to the arti- 

 cles GALLIC ACID and IRON. 



Dr. Lewis first endeavoured to ascer- 

 tain the best proportion between the galls 

 and the sulphate of iron, to render the 

 ink permanent ; for it is to be observed, 

 that with almost any proportions, if the 

 entire quantity be sufficient, the ink will 

 be fine and black at first ; but many of 

 these inks, if kept for some time, espe- 

 cially exposed to light and air, will grow 

 brown and fade, and the letters made 

 with it will become nearly illegible. 



By trying different proportions of galls 

 and sulphate of iron, it was found, that 

 when about in equal quantities (the galls 

 being powdered, and boiled fully to ex- 

 tract their soluble parts) they appeared 

 to be mutually saturated, so that the 

 mixed liquors would receive no additional 

 blackness from a further dose of one or 

 the other. 



This, however, was only a rough ap- 

 proximation to accuracy, for the same ef- 

 fect was produced when either substance 

 was also in a small degree superior in 

 quantity to the other. But Dr. Lewis 

 found that an ink, with equal parts of the 

 two, though very black at first, changed 

 to a yellowish brown, upon exposure to 

 the sun and air only for a few days. This 

 was again blackened by washing with 

 fresh gall infusion, and hence it appears 

 in fair inference that the galls are a 

 perishable substance, so that to insure 

 durability, a much greater proportion 

 must enter into the ink than is required 

 for mere saturation in the first instance. 

 Thus it was found that two parts of galls 

 and one of vitriol make a much more du- 

 rable ink than with equal parts, and three 

 of galls with one of vitriol was still more 

 durable. When the galls were increased 

 beyond this point, the colour was indeed 

 quite permanent, but it was not of so full 

 a black. 



The proportion of water or ether liquid 

 to the solid ingredients will admit of 

 great variation. One part of vitriol, three 

 of galls, and fifty parts of water, gave an 

 ink black enough for common use ; but 

 the finest and blackest was made when 

 only ten of water were employed ; nor 

 was any deficiency in the gallic acid ob- 

 served after fifteen years, though the 

 water was scarcely more than sufficient 

 to cover the galls, and therefore could 

 hardly be supposed capable of extracting 

 all the soluble part of them ; and though 

 the vitriol, from its greater solubility, 

 woald probably be dissolved entirely, 

 and thus be in greater proportion than 

 usual. Other liquors besides water were 

 tried. Of these, white wine and vinegar 

 appeared to answer somewhat better^ ; 



