1835.] Racemic Acid. 243 



When we burn the dry salt in a crucible the zinc is reduced, 

 and at least one half of it is volatilized, so that we cannot 

 determine the composition of this salt by ignition ; nor can 

 we safely trust the loss of weight when heated, as the mea- 

 sure of the quantity of water which it contains. I there- 

 fore precipitated the oxide of zinc from 20 grs. of the salt, 

 by means of carbonate of soda. The oxide of zinc obtained 

 weighed, after ignition, 6 grs. Hence, the component parts 

 of the 20 grs. of salt were 



Racemic acid . . 9*428 or 8*25 

 Oxide of zinc . . 6-000 „ 5-25 



Water 4-572 „ 4-00 



4 water is almost exactly 3 J atoms. From this we see that 

 the salt, when dried in the open air, contains 3| atoms of 

 water. 



XV. RACEMATE OF CADMIUM. 



This salt precipitates when we mix together solutions of 

 sulphate of cadmium and racemate of soda in atomic pro- 

 portions. It is a beautiful white salt, crystallized in small 

 needles. It is tasteless, or nearly so ; its lustre is saline, 

 and its specific gravity 2-64. At the temperature of 52°, 100 

 water dissolve 0-105 of this salt. 100 parts of boiling water 

 dissolve 0-206 of it. 



10 grs. of the salt being exposed for an hour to a heat 

 about 300°, lost 2*4 grs. of weight. The residue being exposed 

 to the heat of a spirit lamp; became yellow, then black, 

 burned like tinder, and gave out a yellow smoke, which con- 

 tained oxide of cadmium. The oxide of cadmium remaining 

 weighed 3*2 grs. Its colour was rather darker than usual. 



The salt being neutral, if we reckon its composition from 

 the loss sustained on the sand bath, its constituents will be 

 1 atom racemic acid . . . 8*25 

 1 atom oxide of cadmium . 8-00 

 4 J atoms water 5-0625 



21-3125 



XVI. RACEMATE OF LEAD. 



This salt precipitates when solutions of nitrate of lead 

 and racemate of soda are mixed together in atomic propor- 

 tions. When washed and dried it is a white powder, with 



r2 



