Explosive reaction of Hud, 



Chio 



rine. 



243 



By calculating the quantity of metallic arsenic, which the metals 

 require in order to consider them as bin-arseniurets, it will be found 

 that 



t 



20.74 nickel takes up 52.84 arsenic, as Ni As'* 



3.37 cobalt " 

 3.25 iron '' 



ii 



a 



8.58 

 9.01 



U 



cc 



Co A5« 



70.43 



The quantity of arsenic thus determined, differs from that actu- 

 ally obtained by something more than 2 per cent ; but as this is evi- 

 dently too large, since it contains the loss unavoidable by analysis, 

 we may conclude that the chemical formula for the mineral is 



Ni 



Or if the small quantities of cobalt and iron be considered as acci- 

 dental, m As^ 



Art, IX. — Explosive Reaction of Hydrogen with Chlorine^ un- 

 der the Lijiuence of the Solar Rays; by R- Hare, M. D. Prof, 

 of Chera. in the Univ. of Penn. 



A flask is half filled with 

 chlorine over the pneumatic 

 cistern, in the usual way, and 

 then transferred to the pan P, 

 so as to have Its orifice exact- 

 ly over that of the orifice of a 

 pipe which, at the other end, 

 communicates with the cock 

 Cj to w^hich is annexed a 

 flexible pipe extending to a 

 seif-regulating reservoir of 

 hydrogen. 



The flask is surrounded by 

 a wire gauze, and just before the explosion is desired, hydrogen from 

 the reservoir is allowed to occupy that portion of the cavity which 

 was previously unoccupied by the clilorine. It should be under- 

 stood that the pan, during this operation, retains a sufficient stratum 



