Polymerization of Formaldehyde. 203 



tion, and gave a slight coloration and turbidity with phloroglucin 

 and HCl. 



A more rapid but less perfect separation than that given above 

 is effected by evaporating the whole synthesized product nearly ta 

 dryness in a water bath, and adding a minimum of cold water. 

 The calcium salt remains undissolved. The filtrate is again 

 evaporated nearly to dryness, and treated with 90% alcohol. The 

 residue consists of sodium tartrate; the filtrate contains the sugar. 



In previous work on sugar synthesis, alkalies have been used 

 singly instead of jointly, and not as here described. As the bye- 

 products described have been saccharates, formates, etc., with 

 which the calcium and sodium salts did not agree, a precise de- 

 termination of their character was necessary. 



Professor E. W. Skeats investigated the crystallographic charac- 

 ter of the calcium salt, and found that it belonged to the ortho- 

 rhombic system, forming pyramids, domes and elongated pinacoid 

 pyramids, with parallel sides. The crystals were strongly, doubly 

 refractive, optically negative, and had a mean refractive index of 

 1.55. Mr. J. W. Clendinnen carried out a complete analysis of 

 pure samples of the two salts. 



Analysis of tufo Crystalline Salts obtained by Professor Ewart. 



The calcium salt was in the form of well defined crystals, and so 

 needed no further treatment to purify it. As the salt was evidently 

 one of an organic acid, simple ignition left a residue of calcium 

 oxide, from which the percentage of calcium could be calculated. 



A combustion was then done with the calcium salt, and this 

 gave the percentages of hydrogen and carbon, and thus oxygen by 

 difference. 



These were the results obtained : — 



Percentag-e. Approx. Ratio 



Element. Duplicates. Mean. At \vk. At wk. x .3Sri. 



Oa - \^^^] - 1.5.4 - .385 - 1 



H - \^] - 4.9 - 4.9 - 12 



C - ^^%] . 18.7 - 1.56 - 4 



O - - 61.0 - 3.81 - 10 



(diff.) 



This formula (CaHjoC^ Oj^) corresponds with that of calcium 

 tartrate CaH4C^Oe.4H„0. The usual quantitative tests for tar- 



