of the Properties of, the refined Ox Gail. 351 
put one ounce of common salt, and continue it on the fire until 
combined; when cold, put it into another bottle, and cork it 
moderately close. 
Gall, thus prepared, will keep perfectly free from putridity, or 
any offensive smell, for years. 
When the above preparations have stood in a room, of a mo- 
derate temperature, for about three months, they will deposit a 
thick sediment, become clear, and fit for use in ordinary pur- 
poses; but as they contain a large portion of yellow colouring 
matter, tingeing blue of a greenish hue, reds, brown, and sullying 
purples, they are unfit for general use in painting in water co- 
lours. 
Further Process. 
The before-mentioned preparations, after standing until become 
perfectly clear, are to be decanted and combined in equal pro- 
portions ; a thick coagulum is instantly formed of the yellow 
colouring matter, which precipitates, leaving a clear liquid, 
namely, the colourless ox gall. 
N.B. After the combination of the two first preparations, the 
process may be assisted by filtering the liquid through paper. 
Age renders this preparation more brilliantly clear, and by it, it 
seems to obtain an agreeable scent ; nor has it been observed to 
contract, at any time, an unpleasant smell, or to lose its useful 
properties. 
Properties. 
The refined ox gall possesses all the valuable properties of ox 
gall, as applicable to painting in water colours, with the superior 
advantages of being deprived of all tendency to putridity, and of 
all colouring matters. 
It combines with, and fixes, all water colours, as they are 
usually prepared, either by being mixed with them, or washed 
over them after they are’ laid upon the paper, &c. It renders 
blue, purple, red, green, and all other delicate colours, more 
bright and durable ; and, if a small portion of it be added to any 
of the colours, it causes them to wash more freely and evenly 
over the surface of the paper, ivory, &c. 
Combined with gum arabic, it gives depth of tint, without any 
unpleasant glossiness upon the surface of the drawing, and_pre- 
vents the gum from cracking ; and the colours are so completely 
fixed in the paper itself, that subsequent tints can be washed 
over them without any risk of their becoming foul, or forming 
improper combinations with the under colours. 
Combined with fine lamp black, and gum water, it forms a 
complete substitute for Indian ink. 
If it be floated over the surface of drawings made with chalks, 
or 
