590 PROCEEDINGS OF THE AMERICAN ACADEMY. 



paratively moderate degree of cooling below its freezing-point by a 

 crystal of pyrosulphuryl chloride in those mixtures which had 5 per- 

 cent or less of silicon, and the crystals obtained in this way gave an 

 analysis indicating a concentration of pyrosulphuryl chloride (14) 

 compared with (18), the mother liquor. Finally several distillates 

 were obtained under certain conditions stated further on, which were 

 almost pure pyrosulphuryl chloride; these cannot be used as proof 

 of its presence because they were obtained at temperatures higher 

 than usual; but taken in connection with the other agreeing observa- 

 tions, they help to establish the fact that pyrosulphuryl chloride is one 

 of the two products of the reaction. With pyrosulphuryl chloride 

 established as one of the products, the table of analyses show beyond 

 a doubt that the other is silicon oxychloride. 



The more regulated action of water on the distillate was next studied 

 in the effort to destroy one substance and isolate the other. In search- 

 ing for a neutral diluant it was found that alcohol, acetone, benzol 

 reacted with the distillate, but carbon tetrachloride, chloroform, and 

 carbon disulphide did not; chloroform and carbon tetrachloride were 

 used. 103 grams of chloroform were mixed with 84 grams of the dis- 

 tillate, the diluted material cooled to —5° and water added drop by 

 drop. Each drop caused the formation of a white ball which when 

 pricked, burst with a slight explosion and formation of hydrochloric 

 acid. The action evidently consisted in the coating of the entering 

 drop with a silica shell; while on pricking, the unchanged water was 

 freed and reacted further. 3 grams of water were added, approxi- 

 mately the amount required to change all the pyrosulphuryl chloride 

 present to chlorsulphonic acid. On transferring the material a sedi- 

 ment of 6.5 grams (silica) was found. A distillation at low pressure 

 removed the chloroform and hydrochloric acid; a distillate of 42 grams 

 was collected, while a semi-solid residue was left in the boiling flask. 

 A second distillation at low pressure gave 38 grams, free from hydro- 

 chloric acid. The density at 18° was 1.73 (pyrosulphuryl chloride is 

 1.837 at 20°). An analysis showed the change produced by the water: 



s Si ci 



(24) Before treatment with water: 16.7% — 49.9% 



(21) After " " "20.1 6.1 43.4 



The figures show that the water attacked mainly the silicon body. 

 A treatment with salt followed and the distillate from the salt mixture 

 was collected, under diminished pressure, in two fractions : the lower 

 one, 9 grams, between 50° and 110°, with oil-bath around the boiling 

 flask raised to 150°; the second, 4.5 grams, with the bath heated to 



