312 
(NH,),C,0, ae HgCl,, (NH,),C,0, = FeCl,, HO; a KMnO, 
and Quinine bisulphate + H,Cr,O,. 
c. Uranium salts are general positive catalysts in photochemical 
reactions, whilst manganese salts are general negative catalysts in 
light and dark reactions alike. 
d. Prrrin’s hypothesis that all chemical reactions are induced by 
radiations support the view that the effects of temperature and of 
light on chemical reactions are of an identical nature. 
e. A solution of ammonium cupric oxalate decomposes with the 
separation of metallic copper and evolution of CO, in tropical sunlight, 
but not in carbon-are-light or the zirconium + thorium oxides-are- 
light. 
Chemical Laboratory, Muir Central College, 
Allahabad, India. 
