Manchester Memoirs, Vol. Hi. (1908), No. |2 9 



rapid blackening of the lead paper, that it occurred to 

 me that it might be due to the arsine itself and not to 

 any reaction on the selenium that was being exposed to 

 it. This led me to remove the selenium tube and allow 

 the gas to act on a fresh paper moistened with solution 

 of lead acetate. This was rapidly darkened and the stain 

 had very much the appearance of papers stained with lead 

 selenide and telluride. These stains are distinguished 

 from those due to lead selenide and telluride by not 

 altering when treated with either strong or dilute hydro- 

 chloric acid. 



On allowing arsine to bubble through solution of 

 lead acetate contained in a wash bottle, the liquid soon 

 darkens in colour and a black precipitate separates. 

 Subsequently a black shining mirror forms on the sides 

 of the bottle and adheres firmly to the glass for some 

 days, when it drops off. 



I can find nothing in the precipitate but lead and 

 arsenic, but on making quantitative determinations I 

 found such varying proportions of the two elements in 

 different preparations, that I could only conclude that 

 the compound is probably an arsenide of lead but not of 

 definite composition. 



Similar experiments with stibine showed that this 

 gas has no action on solution of lead acetate. 



