296 Mr. T. E. Thorpe on the [Feb. 17, 



The specific gravity at 75°-90 is 1-46900, and accordingly the specific 



T0lumeis iSi =93 ' 52 - 



Pierre has found that the expansion of phosphorus chloride may be 

 represented by the formula* 



V = 1 + 0-001 128 618 932*+ 0-000 000 872 880 045* 2 



+ 0-000 000 017 923 565* 3 , 



which gives results agreeing fairly well with those calculated by means 

 of the expression deduced from my observations. 



10°. 



Pierre 1-01139 



Thorpe 1-01147 



The specific gravity of phosphorus trichloride at various temperatures 

 has also been determined by Buff f. The results of the several observa- 

 tions are : — 



Sp. gr. at B.P. B.P. Spec. vol. 



Buff 1-47102 76-0 93-39 



Pierre 1-46601 78'34 93-71 



Thorpe .... 1-46900 75-90 93-52 



30°. 



50°. 



70°. 



1-03513 



1-06085 



1-08943 



1-03557 



1-06138 



1-08911 



Mean 93-54 

 VII. Arsenic Trichloride. 



This compound was obtained by heating arsenic trioxide in a current 

 of dry chlorine. It was distilled upwards in a current of dry carbon di- 

 oxide for some time in order to expel the excess of chlorine. Care is 

 necessary to obtain a perfectly clear product • the least trace of moisture 

 renders the liquid turbid from the formation of the insoluble oxychloride, 

 AsClO. On distillation the liquid commenced to boil at 129°-23, and all 

 came over below 129°-33, the greater portion boiling at 129 o, 30. n= 

 16°, 2' = 15°-5. Bar. 733*4 millims. Corrected and reduced boiling-point 

 130°-21. 



Its specific gravity at 8°-08, compared with water at the same tempe- 

 rature, was 2-18761 • compared with water at 4° its specific gravity is 

 found to be 2-20500. 



Other observers have given for the boiling-point and specific gravity of 

 arsenic trichloride — 



t» t> -D Sp. gr. compared with 



• B,r - ■"*?■ water at 4°. 



e millim. 



Pierre 133-81 765-9 2-20495 at 0° 



Haagen 128-0 754-0 2-1668 at 20° 2-20671 „ 



* Loc. cit. p. 10. The third term is erroneously printed 000001 79 .... 

 t Loc, cit. 



