160 Dr. A. E. Everest and Mr. A. J. Hall. 



(ii) Effect of metallic salts on aqueous solutions of violanin chloride :— 



(a) Addition of magnesium acetate gave a fine blue (with violanin 

 mixed with quercitrin, green). 



(b) Addition of ferrous sulphate gave a fine blue (with violanin mixed 

 with quercitrin, green). 



(c) Addition of copper sulphate produced a fine purple-blue, which 

 passed to pure blue on warming, returning to purple-blue on cooling. 



(iii) Cyanide chloride when in alcoholic solution behaved exactly like violanin 

 chloride when magnesium acetate, anhydrous sodium acetate, or potassium 

 acetate was added, a fine blue colour, followed by deposition of the blue 

 pigment, being the result in each case. 



(iv) Further observations that have been made by the present authors, and 

 which have direct bearing upon the paper under discussion, are those upon 

 the effect of adding various metallic salts to solutions of the colourless form 

 of violanin. A solution was prepared by dissolving crystalline violanin 

 chloride in a little alcohol, pouring this into water, and allowing to stand until 

 decolorised. Separate portions of the solution were taken and salts added, 

 with the results given below. (In each case one drop of a dilute solution 

 of the salt was used.) 



(a) Ferrous Ammonium Sulphate : no immediate colour, but fine blue 



gradually appeared. 

 (h) CUSO4: no immediate colour, but fine blue gradually appeared. 



(c) SnCl2 : no immediate colour, but fine blue gradually appeared. 



(d) FeCls : great difficulty iu obtaining colour as oxidation with destruc- 



tion of pigment occurred; if very dilute solution of FeCls was 

 used, got fair but pale blue. 



(e) CaCls : at once very pale green but colour did not increase. 



(/) Magnesium Acetate : at once very pale green but colour did not 

 increase. 



(g) Lead acetate : at once very pale green but colour did not increase. 



(h) Sodium Acetate : at once very pale green but colour did not increase. 



(i) l>ra2C03: rapidly yellow gieen; on standing, yellow and pigment 



destroyed. 



