1836.] on Racemic Acid. 169 



10 grs. of this salt, after exposure for some hours to a 

 heat of 340°, lost 1.66 grs. The residue, which was still 

 white, being ignited in a platinum crucible, became black. 

 Being drenched in nitric acid, and again ignited, there 

 remained 2*30 grs. of pure white alumina. If we suppose 

 the heat of 340° sufficient to drive off all the water, it is 

 obvious that the salt was composed of 



Racemic acid . 6*04 or 8*25 

 Alumina . . . 2-30 „ 3-141 

 Water. . . . 1-66 „ 2*26 

 2*26 is almost exactly 2 atoms of water; and 3' 141 is very 

 nearly If atoms alumina. I have some doubts whether the 

 f ths of an atom of alumina was really united with the acid ; 

 for, when the salt was ignited it was converted into a black 

 mass, through which white dots were scattered. I think it 

 not improbable, that these white dots were portions of alu- 

 mina, which had not been united to the acid. If this sup- 

 position be well founded the constituents of the salt will be 

 1 atom racemic acid . . 8*25 



1 atom alumina . . . 2*25 



2 atoms water .... 2*25 



12-75 

 Tartaric acid acts in a very different manner on alumina 

 than racemic acid does. It dissolves hydrated alumina with 

 facility, and, on evaporation, it forms a viscid transparent 

 matter, like gum-arabic. It has an acid and sweetish taste, 

 and is probably a bi-tartrate. When washed with water a 

 white matter remains, brittle, and easily reduced to powder. 

 It is tasteless and neutral, and is composed of 



1 atom tartaric acid . . 8*25 

 1 atom alumina . . . 2*25 

 1 atom water .... 1*125 



11-625 



X. RACEMATE OF IRON. 



Racemic acid dissolves iron by the assistance of heat, 

 with the evolution of hydrogen gas, and soft white needles 

 of racemate of iron are deposited. The easiest method of 

 obtaining this salt is to dissolve 173*75 grs. of crystallized 

 sulphate of iron in 4 cubic inches of boiling water ; to put 

 the solution into a phial, which it almost fills. 122J grs. of 



