180 Journ. of the Asiat. Soc. of Bengal. [July & Aug., 1915. 
type Ag,O, AgCl 
Richardson (J. C. S. 1892) on the other hand was of opinion 
loss of weight to take place when AgCl loses chlorine in light a0 
by Sahler (Phot. Mitt. Bd. 13) who showed that Ag(Cl darkens 
in pure nitrogen very slowly compared with oxygen. 
: H. B. Baker (J.C.S. 1892) aaa that when ke is confined 
in a bulb and exposed to light over strong KOH that contrat 
tion of the air inside the bulb takes place, and moreovel that 
the darkened product yields water when acted upo b 
hydrogen in a furnace. Completely pure AgCl did not darket 
in vacuo, nor in : It did n0 
and allowing for absorption of oxygen by the copper: 
reduced Ag was measured by aoiitia on Ae darkened product | 
