Page:Experimental researches in chemistry and.djvu/195

180 The solution (b) was almost tasteless, and when dried left a green, shining, brittle substance, re soluble in water, and of course precipitable by alcohol. It colours solution of per sulphate of iron green; but if its strong aqueous solution be treated with muriatic acid, a reddish-brown precipitate is formed, which, when separated, dissolves in water, does not colour persalts of iron, and when evaporated yields a pulverulent substance, burning, but not with facility, and producing a little ammonia when heated in a tube.

The alcoholic solution from which these matters had been separated contained the particular principle which colours persalts of iron green. When evaporated it left a brown, brittle, transparent substance, becoming soft by exposure to moist air. It is very bitter, soluble in water, &c., slightly acid. When heated on platina-foil, it does not burn easily, but runs out into a bulky charcoal, much like animal matter; at the same time it does not yield ammonia when heated in a tube per se, though the smell is very like that of animal substance.

Ether warmed with it di solved a small portion of matter, and the solution, upon evaporation, left globules, which, in all their characters, corresponded with wax; its quantity was but small.

Nine hundred and eighty-one grains of the original sap were washed in water several times. The washed caoutchouc, being coagulated by heat and perfectly dried, weighed 311 grains. The aqueous solutions, upon being boiled, yielded sufficient of the heavy precipitate to equal, when dried, 18.6 grains. The clear solution was now evaporated to dryness and digested in alcohol, 28.5 grains of insoluble matter were left, and the solution, upon evaporation, afforded 70 grains of dry matter. Hence the following are the contents nearly of 1000 parts of the original sap:-