4 Jones, Selenium and Tcllnrhiui on Arsinc and Stibinc. 



{b) At a teniperatnre of lodC. 



Arsine was passed over selenium contained in a 

 U-tube which was immersed in boiHng water, and the 

 whole apparatus was screened from daylight. There was 

 no difference in the appearance of the tube at the con- 

 clusion of the experiment, and on testing the contents 

 the absence of arsenic was proved, so that arsine is not 

 decomposed by selenium at the temperature of boiling 

 water. 



ic) In tJic dark. 



Arsine was passed over selenium contained in a tube 

 screened from light. The gas was jaassed for several 

 hours but no reaction occurred. 



Action of Tcllnriiini on Arsine. 



(a) In sunlight. 



Arsine was passed for three hours over powdered 

 tellurium contained in a straight glass tube. At the end 

 of the experiment there was no visible change in the 

 appearance of the tellurium, but on removing it from the 

 tube and heating it in a test tube, a sublimate formed 

 which, under the microscope, was seen to consist of 

 distinct octahedral crystals. These were dissolved in 

 water, hydrochloric acid and sulphuretted hydrogen were 

 added, and a yellow precipitate of arsenic tri-sulphide 

 appeared. So that in presence of sunlight, tellurium 

 decomposes arsine. 



{b) At a temperature of loo'^C. 



Arsine was passed over powdered tellurium contained 

 in a U-tube protected from light and kept at a tempera- 

 ture of lOO^C. After more than three hours treatment 

 the action was stopped and the contents of the tube tested 



