Sadtler.] olo [Sept. 17, 



t 



The colorless or light straw-colored filtrate is somewhat concentrated, 

 and calcic carbonate is added to neutralization. The solution is filtered, 

 if necessary, and to the filtrate is added an equal volume of 95 per cent, 

 alcohol. The calcium salts present are all precipitated, in greater part 

 at once, and completely on standing twelve hours. 



If the solution had been very concentrated the calcium salt is precipi- 

 tated in a granular condition. If, on the other hand, it was more dilute, 

 the salt only separates gradually, and has a beautiful micaceous and scaly 

 appearance. 



I had at first considered this precipitate to be pure calcium glycerate, 

 but found on dissolving it in water, in order to free it from the lime and 

 obtain the glyceric acid, that while the greater portion dissolved readily 

 in warm water, a considerable portion, although not more than one-tenth 

 of the whole amount, remained and dissolved only on continued boiling. 

 This, when filtered off and washed in cold water, appeared as a dull 

 white almost impalpable powder, contrasting in appearance with the 

 crystalline glycerate. 



It was dried carefully at 100° until constant weight was obtained. 



Calcium determinations were first made. Weighted portions were 

 ignited in a platinum crucible once or twice with excess of concentrated 

 sulphuric acid until the weight remained constant. 



.5755 grms. salt yielded .4925 grms. CaSO^ equal to 25.22 per cent. Ca. 



.1759 grms. salt yielded .1505 grms. CaSOj. equal to 25.16 per cent. Ca. 



The theoretical per cent, of calcium in calcium tartronate is 25.33, 

 while in calcium glycerate, allowing for two molecules of water of crys- 

 tallization, it is 13.99. 



I had analyzed the micaceous preparation of calcium glycerate about 

 the same time and had gotten in two determinations, 14.03, 14.07 per 

 cent, of calcium respectively. The difference was so great that I could 

 not imderstand it. On reckoning up the molecular weight, however, 

 assuming one atom of calcium to be present, I got 159. The molecular 

 weight of calcium tartronate is 158. Being dibasic, the molecular 

 weight of the calcium compound is of course much less than the weight 

 of the calcium compound of glyceric acid, a monobasic acid. 



I endeavored twice to make a combustion of the salt in order to get the 

 per cent, of hydrogen and carbon. Each time calcium carbonate re- 

 mained undecomposed at the heat of the combustion. I therefore gave 

 them up. 



I then took the remainder of my salt, grown rather small, to my great 

 regret, and neutralizing the lime with oxalic acid, obtained the free 

 acid. This, on concentration, deposited out crystals. On examination 

 with a lens they were seen to be of tabular form, well agreeing with the 

 appearance of tartronic acid obtained from nitro-tartaric acid. A com- 

 bustion was made of these, and here, unfortunately, an accident to the 

 potash bulbs lost me the carbon determination. The hydrogen determi- 

 nation however, is given. 



