94 Historical Sketch of Improvements in [ACG. 



matter of ambergris by the name of ambreine. It may be 

 obtained by digesting ambergris in hot alcohol of the specific 

 gravity 0*827 . The alcohol on cooUng deposits the ambreine in 

 very bulky and irregular crystals, which still retain a very consi- 

 derable portion of alcohol. Thus obtained, it possesses the 

 following properties : 



It is of a brilliant white colour, has an agreeable odour, of 

 which it is deprived by repeated solutions and crystallizations. 

 It is destitute of taste, and does not act upon vegetable blues. 

 It is insoluble in water, but dissolves readily in alcohol and ether, 

 and in much greater quantity in these liquids when hot than 

 when cold. It becomes soft when heated to the temperature of 

 77°, and melts at the temperature of 86°. When exposed to a 

 temperature exceeding 212°, it flies off in the state of a white 

 smoke, while a portion of it is decomposed. 



It does not seem capable of combining with an alkali, or of 

 being converted into a soap. When heated with nitric acid, it 

 becomes green and then yellow, while nitrous gas is exhaled. 

 By this absorption of oxygen, it is converted into an acid to 

 which Pelletier and Caventou have given the name of ambreic 

 acid. 



Pure ambreic acid is yellow while in a considerable mass, but 

 when spread thin, it is nearly white. It has a pecuhar smell. It 

 reddens vegetable blues. When heated, it does not melt even 

 at the temperature of 212°, and when heated till it undergoes 

 decomposition no ammonia is given off. It dissolves readily in 

 alcohol and ether. It is likewise soluble, but only in a very 

 small degi'ee in water, though hot water dissolves more of it than 

 cold water. The solution of this acid may be saturated with 

 potash. When the alkali is added rather in excess, no precipi- 

 tate appears, even when the hquid is concentrated by evapora- 

 tion ; but if the alkaU be added only in sufficient quantity to 

 saturate the acid, white flocky precipitate falls, which is a super- 

 ambreate of potash. Ambreate of potash forms a yellow 

 precipitate when mixed with solutions of the following salts : 



Muriate of lime, Acetate of lead. 



Muriate of barj-tes, Corrosive sublimate. 



Sulphate of copper, Muriate of tin, 



Sulphate of iron. Muriate of gold. 

 Nitrate of silver. 



The gold in the last precipitate is not reduced till after an 

 interval of some hours, (.lour, de Pharm. v. 49.) 



4. Animal Charcoal. — This substance appears to be a com- 

 pound of carbon and azote. We are at present acquainted with 

 three compounds of these two bodies. 



(1.) Cyanogen composed of two atoms carbon and one atom 

 azote. 



(2.) Azoiuret of carbon, observed by Ga\^Lussac imder the 



