1835.] on Racemic Acid. 101 



two atoms of water, that we can entertain no doubt that 

 the crystals consist of a compound of one atom of acid with 

 two atoms of water. Why I have pitched upon 8'25 for the 

 weight of the acid will appear immediately. 



Tartaric acid crystals consist of only 1 atom of water 

 united to 1 atom of acid. It contains, therefore, just half 

 the water in racemic acid ; but with this water it will not 

 part without undergoing decomposition. Racemic acid, 

 when heated to 150° gives off one-fourth of its water ; at the 

 same temperature tartaric acid loses no weight whatever. 



3. 20 grs. of neutral racemate of lead (previously dried 

 in a low heat) were exposed for two hours on a glass capsule 

 to the temperature of 250°. The weight was reduced to 

 16*16 grs. The heat being continued for two hours longer, 

 and raised a little higher, the weight was reduced to 16*12 

 grs. But the powder where in contact with the glass had 

 become yellow, indicating an incipient decomposition of 

 the acid. 



The residual 16*12 grs. were ignited in a porcelain cruci- 

 ble. Most of the lead was reduced to the metallic state. 

 The whole weight was 9*49 grs. Of this 9*18 grs. were 

 metallic lead, and 0*1 gr. protoxide of lead. The remaining 

 0*2 gr. were probably charcoal from the acid, for they 

 disappeared on treating the lead with nitric acid. Now, 

 9*18 lead + 0*1 protoxide of lead = 10*188 grs. of pro- 

 toxide of lead. It would appear then, from this experiment, 

 that racemate of lead is a compound of, 



Racemic acid 5*972 or 8*206 



Protoxide of lead . . . .10*188 „ 14* 



16*160 



The result of this analysis gives us 8 206 for the atomic 

 weight of racemic acid. The only ground of doubt respecting 

 this analysis is the uncertainty whether any of the acid had 

 been decomposed by the heat. So far as the eye could 

 determine the salt was unchanged. 



4. An analysis of racemate of lime conducted in the same 

 way led to results not differing much from the preceding ; 

 it seems, therefore, needless to detail the analysis. For 

 the same reason the details of the analyses of racemate of 

 barytes and racemate of strontian, which were also made. 



