INKS. 393 



pretty thick solution of gum-arabic in water, and, having mixed it 

 with the powder, grind the whole on a stone, in the same manner 

 as colour. nun grind their colours. Nothing is then necessary, 

 but to put the paste into some small moulds, formed of cards, and 

 rubbed over with white wax, to prevent it from adhering to them. 



In regard to the smell of the China ink, it arises from a little 

 musk, which the Chinese add to the gum. water, and may easily be 

 imitated. The figures seen on the sticks of China ink, are the par. 

 ticular marks of the manufacturers, who, as in all other countries, 

 are desirous of distinguishing whatever comes from their hands. 



Dr. Lewis thinks, from the information of Father du lialde, that 

 China ink is composed of nothing but lamp black and animal glue. 

 Having boiled a stick of China ink in several portions of water, in 

 order to extract all the soluble parts ; and having filtered the dif. 

 fen nt liquors, which he evaporated in a stone vessel, he found 

 that the liquors had the same odour as glue, and that they left, after 

 evaporation, a pretty considerable quantity of a tenacious sub- 

 stance, which seemed to differ in nothing from common glue* 



Coloured INKS. Few of these are used except red ink. The 

 preparation of this is very simple, consisting either of decoctions 

 of the different colouring or dying materials in water, and thickened 

 with gum-arabic, or of coloured metallic oxides, ox insoluble pow- 

 ders, merely diffused in gum water. The proportion of gum. 

 arable to be used, may be the same as for black writing ink. All 

 that applies to the fixed or fugitive nature of the several articles 

 used in dyeing, may be applied in general to the use of the same 

 substances as inks. 



Red I.\K is usually made by boiling about two ounces of Bra. 

 til wood in a pint of water, for a quarter of an hour, and adding to 

 the decoction the rr-qui-ite quantity of gum, and about half as much 

 alum. The alum both heightens the colour and makes it less fugi. 

 the. Probably a little madder would make it more durable. 



Blue INK may be made by diffusing Prussian blue or indigo 

 throuh strong gum. water. 



Yellow INK may be made by a solution of gamboge in gum- 

 water. 



Most of the common water-colour cakes diffused in water, will 

 make sufficiently good coloured inks for most purposes. 



Inks of other colours may be made from a strong decoction of 

 the ingredients used in dying, mixed with a little alum and gum. 



