586 PROCEEDINGS OF THE AMERICAN ACADEMY. 



introduced into a special separator^ ^, crystallized and the mother 

 liquor drawn off; the crystals were then allowed to melt, drawn off in 

 their turn, and analyzed. Only the fraction 138-143° was not sepa- 

 rated into crystals and mother liquor, because its amount was too 

 small. 



These analyses show that the fractional distillation gives little or 

 no promise of leading to a pure product as the percentages of sulphur 

 and silicon in the different fractions differ by 1.1 percent or less, 

 those of chlorine by 3.56 percent or less Nor is crystallization more 

 promising since there is essentially no difference in composition be- 

 tween the crystals (10, 11) and their mother-liquor (12, 13). 



Another preparation similar to the last was allowed to stand for 

 three summer months in a glass stoppered bottle under a bell-jar 

 whose atmosphere was kept dry by phosphorous pentoxide; during 

 this time a solid amounting to 23 percent of the total weight was 

 deposited, and on distillation a fraction of 53 grams or 38 percent 

 boiling at 136-156° was obtained. This fraction when cooled to —78° 

 did not crystallize, but on inoculation with a crystal of pyrosulphuryl 

 chloride it did, so many crystals developing that it became a stiff 

 paste; this had been done in the separator, and after warming a little, 

 the mother liquor was drawn off; the process was repeated twice, the 

 melted crystals serving as starting material each time. After making 

 an analysis (14) of the final crystals, a portion of the original 53 grams 

 was taken and the crystallization was repeated, but this time with an 

 alcohol bath cooled to —65° and —60° instead of —78°, in order to 

 reduce the supercooling. The material was fractionally crystallized 4 



18 Sanger and Riegel, These Proceedings, 47, 710. It consisted essentially 

 of a glass vessel holding a platinum cone, and connections above and below 

 so that suction might be applied below or above, all out of contact with moist 

 air. 



