1835.] Improvements in Science. 123 



the air, and a current of sulphuretted hydrogen passed 

 through it. 



The filtered solution possessed a pale yellow colour, 

 which by evaporation, free from the action of air, yielded 

 a thick pale opaque yellow mass, which was crenic acid in 

 the purest state. 



Crenic acid is yellow, destitute of any appearance of 

 crystallization, without smell, and in the dry state it tastes 

 acid, but in a dilute solution, produces no effect on the 

 tongue, although it reddens litmus paper. It dissolves in 

 all proportions in water and absolute alcohol. The alco- 

 holic solution evaporated in the air becomes brown. The 

 aqueous solution when dried assumes the appearance of a 

 syrup. When distilled, it affords an acid liquor and a 

 brownish yellow oil. Distilled with caustic potash, ammo- 

 nia is produced. While in the retort charcoal remains, 

 which burns completely away when the acid is pure. 

 Crenic acid consists of carbon, hydrogen, azote and oxygen, 

 in proportions which have not yet been determined. 



It dissolves in nitric acid in the cold without change ; by 

 the application of heat some nitrous gas is disengaged, 

 and nitric acid may be distilled off. By evaporation a yel- 

 low mass is left in the water, possessing an intensely bitter 

 taste, which unites with an alkali when the latter is added 

 to it, forming an alkaline crenate. 



When silica is separated from a crenic acid solution, the 

 precipitate contains crenic acid which can be separated by 

 an alkali; but the silica by heating becomes black and 

 disengages an animal smell, and when moist is dark grey, 

 when dry, white. 



The compounds of crenic acid and the alkalies are easily 

 soluble in water, and in concentrated solutions resemble 

 vegetable extracts. The salt3 of the alkaline earths are 

 less soluble, and those of the metallic oxides difficultly 

 soluble, but dissolving more or less by washing. 



To determine the atomic weight of crenic acid, a solution 

 of acetate of lead was precipitated by a portion of pure cre- 

 nic acid ; the precipitate was white by reflected, and yellow 

 by transmitted light. It was washed and dried, free from 

 access of air at a temperature of 100° C (212° F.) It weighed 

 0*59 grm. ; decomposed by sulphuric acid 0*4165 grm. of 

 sulphate were obtained, dried at the same temperature. 



