

April. 1915. 



KNOWLEDGE. 



99 





I 



a. Spectrum of the blue flame of illuminating gas. 



b. Caesium chloride. Flame spectrum. 





.?-'.< ■/>'.' '-<■ i >•> j/t'i' tyo //tf /!,,• 



c. Rubidium chloride. Flame spectrum. 



(I. Potassium chloride. Flame spectrum. 



it>o ItO 



!-■'■ I '■■ Jj,y 



>■ Potas in::: ulphate (fused). Spark spectrum. 



■ 



z. 

 f. Sodium sulphate (fused). Spark spectrum. 



I I'.l Rl 



