INK. 



but any considerable proportion of spirit 

 of wine, or brandy, obviously did harm, 

 owing to the insolubility of the sulphate 

 of iron (as of all the other sulphates) in 

 alcohol, and therefore its diminished so- 

 lubility in any liquor is in proportion to 

 the alcohol it contains. A decoction of 

 logwood used instead of water sensibly 

 improved the beauty of the colour. 



Instead of galls other astringents were 

 employed, such as sloes, oak-bark, tor- 

 mentil root, &c. ; but though they all 

 gave a good blue black, with the salt of 

 iron, none of them was equal to the gall- 

 nut in this respect. 



Other salts of iron were also substitu- 

 ted to the sulphate. The muriate and 

 nitrate of iron neai-ly equalled the sul- 

 phate in colour, but proved too corrosive 

 to the paper, and as they were in no re- 

 spect preferable to the sulphate, there is 

 no reason for abandoning it. 



Imagining that there must be some ex- 

 cess of sulphuric acid in common ink, t.o 

 which the fading might be imputed, Dr. 

 Lewis tried to neutralize it by lime and 

 alkalies, but with manifest injury, the 

 colour being re-ndered thereby extreme- 

 ly fugitive. Another ingenious idea for 

 avoiding the supposed excess of acid was, 

 to separate the black atramentous preci- 

 pitate, wash it, and again diffuse it with 

 water thickened with gum. This, indeed, 

 makes a very good ink, but with the capi- 

 tal defect of not remaining so long sus- 

 pended in the liquor, and especially of 

 not fixing itself to the paper like com- 

 mon ink, but rather only slightly adhering 

 like a weak gum varnish, and was readily 

 washed off by water. Hence it appears 

 that the acid of the salt of iron acts as a 

 kind of mordant, or intermede, between 

 the atramentous precipitate and the pa- 

 per, and causes a degree of chemical 

 union between them ; a real advantage 

 which this species of ink possesses over 

 all the lamp-black, or China inks, which, 

 indeed, are rather black varnishes. 



With regard to the gummy ingredient, 

 the effect of which is rather mechanical, 

 it was found that any other gum-mucilage 

 would answer as well ; but not glue, isin- 

 glass, nor animal jelly of any kind. Be- 

 sides, as these latter putrify by keeping, 

 this alone would be a strong objection 



Sugar is sometimes added to ink. It 

 makes it flow somewhat easier from the 

 pen, andgivesit when dry a gloss which 

 is admired by some. It has this quality, 

 however, of making it very slow in dry- 

 ing, which in most cases is an inconve- 

 nience. 



On account of the great improvements 



to the black atramentous dye produced 

 by adding sulphate of copper, some have 

 recommended this addition to common 

 ink, which is composed of the same ma- 

 terials ; but it does not appear that the 

 same advantage is here obtained, and Dr. 

 Lewis thinks it an useless addition. 



From the above observations, Dr. 

 Lewis gires the following receipt for the 

 composition of ink : put into a stone or 

 glass bottle, or any other vessel, three 

 ounces of finely powdered galls, one 

 ounce of green vitriol, one ounce of log- 

 wood finely rasped or bruised, one ounce 

 of gum-arabic, and a quart of soft water ; 

 shake the bottle well, and let the ingre- 

 dients stand in a moderately warm place 

 for a week or ten days, shaking it fre- 

 quently in the day. It is then fit for use; 

 but a little before it is put into the ink- 

 stand, it is better to shake the bottle, that 

 the colour may be more uniformly dif- 

 fused. 



To prevent the ink from moulding, 

 Hoffman recommends half a dozen cloves 

 to be bruised with the gum-arabic, and put 

 into the bottle. This appears a useful 

 addition. Instead of water alone, where 

 a very fine ink is wanted, white wine, or 

 vinegar and water, may be used. 



If the ink be wanted for use in a very 

 short time, the galls and logwood may be 

 boiled far half an hour in the water, 

 adding a little tno?e to supply the waste, 

 and the decoction while hot strained off 

 through a cloth, and the gum arabic and 

 cloves, and the sulphate of iron, both in 

 fine powder, added to the decoction 

 when in the bottle and shaken. The ink 

 will then be fit far use almost immediately 

 after the latter ingredients are dissolved. 

 It will be improved by adding to the bot- 

 tle some pieces of gall-nut coarsely bruis- 

 ed. Ink kept in a close bottle is always 

 rather pale ; but it blackens by exposure 

 to air in a few hours ; and probably in 

 this way the colour is somewhat more 

 durable than if it were brought by pre- 

 vious exffttsure to its full colour at once. 



It has been mentioned that sugar ren- 

 ders ink slow in drying. Advantage is 

 ingeniously taken of this property in ena- 

 bling it to give one, and sometimes two 

 impressions on soft paper, when strongly 

 pressed. In this simple way letters are 

 copied in merchant's counting houses, 

 and offices of business. A little sugar is 

 mixed with the ink, the writing-sheet is 

 laid on the copying press, a blank sheet 

 of porous and damped paper is put over 

 it, and by the pressure of the machine a 

 perfect fac-simile of the writing is struck 

 off, sufficiently legible for all purposes* 



