20 ALKALIES PRODUCE YELLOW LIGHT. 



those of CHLORINE, that it also holds a minute quantity of the 

 YELLOW (nitrogen) ray in its constitution. 



Bromine would appear to be somewhat analogous to chlorine ; 

 it also bleaches, and may have the three elements in its compo- 

 sition from its color, reddish-brown, when boiled, exhibiting 

 the red and yellow, and from the hyacinth-red solution a por- 

 tion of hydrogen, which, on addition of water as a menstruum 

 of solution, containing the red (oxygen} ray and the blue (hy- 

 drogen) ray in EXCESS, affords the red hyacinth color alluded 

 to. 



The three alkalies are composed of nitrogen, the yellow ray, 

 with various portions of the other rays. 



Sodium inflames in atmospheric air. When thrown on the 

 surface of water it decomposes with a hissing noise ; disengages 

 hydrogen, occasionally exhibits a yellow flame when nearly in 

 contact with the sides of the vessel, or on its first direct contact 

 with the water. But it burns on hot water with a bright yellow 

 light. 



Sulphuret of sodium. Sulphur and sodium, when heated 

 together in a glass tube, exhibit much heat and light, and form 

 sulphur et of sodium. 



Sulphate of sodium, mixed with charcoal, form an impure 

 sulphuret of sodium. It is semi-transparent, and of a flesh-red 

 color. While sulphur, boiled in a solution of caustic soda, 

 affords sulphuret of soda, in solution of a greenish-yellow 

 color. 



Nitrate of soda is used to give a yellow color to the flame 

 of fireworks. 



Dr. Clark has observed that phosphate of soda, when ig- 

 nited, acquires, as a ^vo- phosphate, new properties ; and when 

 re-dissolved in water, crystallizes in a different shape, and with 

 a different number of atoms of water, from the common phos- 

 phate. Its solutions, also, when mixed with solutions of silver, 

 yield a white precipitate of neutral phosphate of silver ; where- 

 as, the common phosphate produces a yellow precipitate of sub- 



