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like the fluid or soft parts of animals; as does likewisethe clear water, after the black matter has settled andbeen separated from it. The Indian ink appears there-fore to contain an animal substance soluble in water; andto consist of a black powder mixed with some animalglue. For the greater certainty in regard to this conglu-tinating ingredient, I boiled one of the China cakes inseveral fresh portions -of water, that all its soluble partsmight be extracted, and having filtered the liquors throughpaper, set them to evaporate in a stone bason : they smeltlike glue, and left a very considerable quantity os a tena-cious substance, which could not be perceived to differ inany respect from common glue.

Being thus convinced of the composition of the mass,I tried to imitate it, by mixing some of the lamp-black,which I had myself prepared from oil (see page 342) withas much melted glue as gave it sufficient tenacity for be-ing formed into cakes. The cakes, when dry, answeredfully as well as the genuine Indian ink, in regard both tothe colour, and the freedom and smoothness of working.Ivory-black and other charcoal blacks, levigated to agreat degree of fineness, which requires no small pains,had the same effect with the lamp-black; but in the statein which ivory-black is commonly fold, it proved muchtoo gritty, and separated too hastily from the water.

III. Compofition for marking sheep .

Great quantities of wool are annually made unser-viceable by the pitch and tar, with which sheep aremarked, and which are commonly not laid on with a spa-ring hand, as they considerably increase the weight of thefleece at a trifling expence. With a view to prevent, asmuch as possible, this great waste of so useful a commo-dity, the society instituted in London for the encourage-ment