<S Jones, Sclodmu and Telliiriinii on Arsine and Stibine. 



to be noted that the action of these hydrides on sulphur, 

 selenium, and tellurium corresponds with the rise in the 

 atomic weights of these elements. This is shown by the 

 comparative rapidity with which the action takes place in 

 each case, stibine being readily decomposed by selenium 

 and more slowly by tellurium exposed to sunlight, 

 whereas arsine reacts on selenium slowly and on tellurium 

 only very slowly. The fact that stibine is decomposed 

 by selenium, even in the dark is, of course, a marked 

 exception. I have previously shown that paper coated 

 with sulphur when in contact with stibine and exposed 

 to light, may be used like sensitive paper in photographic 

 printing, the exposed portions becoming orange coloured 

 owing to the deposition of antimony trisulphide, the 

 protected parts retaining the yellow colour of the sulphur. 

 In a similar way paper coated with selenium and kept in 

 contact with stibine may be used as printing paper, but 

 there is, of course, not so great a contrast between the 

 colour of the antimonj' selenide deposited and the 

 selenium, as there is between the orange-coloured anti- 

 mony trisulphide and the sulphur. 



Action of Arsine on solutions of Lead. 

 I have already referred to the action of arsine on 

 solution of lead acetate as preventing the adoption of 

 the lead paper test with this gas. It is .'surprising that 

 this reaction seems hitherto to have escaped observation, 

 seeing how thoroughly the behaviour of both arsine 

 and stibine with reagents has been investigated. In 

 Gmelin's " Handbook," vol. 4, pages 268 and 335, it is 

 stated on the authority of Simon that arsine and stibine 

 do not act on lead acetate, and I have not found any 

 other statement on the subject. In the course of the 

 experiments above described I found in one case such a 



