14 ELECTRIC At EXPERIMENTS. 



Alkali andal- Sulphate of potash affords a small spark, and is luminous 

 Valine salts. . ,, , T 

 by the shock. 



Nitrate of potash, commonly called nitre or salt-petre^ 

 affords a spark which is beautifully flame-coloured on its 

 surface; it is also luminous, but its light is of short du* 

 ration. 



Muriate of potash is much more phosphorescent than 

 nitre, and its light is of longer continuance. 



Hyper-oxymuriate of potash is lumious, but does not ex- 

 plode when the shock is passed through it. 



Acidulous oxalate of potash is luminous by the electric 

 shock. 



Acidulous tartrite of potash. Red and white argol, and 

 purified crystallized cream of tartar afford similar results, 

 except that cream of tartar is rather more luminous than 

 the others. They do not give a spark ; but a cake of con- 

 glomerated crystals allows a spark to pass through it, ren- 

 dering it almost transparent. 



Neutral tartrite of potash, of soluble tartar of the apo- 

 thecaries, is rendered luminous by the explosion. 



Tartrite of potash and soda, orRocltelle salt of the apo- 

 thecaries, affords a beautiful spark, flame coloured, and 

 ramified upon the surface, when a single crystal is made use 

 of; but when one crystal is placed upon another, and the 

 discharger applied to the uppermost, only a purple hissing 

 stream or a very slight spark can be taken from it. It is 

 luminous when the shock is passed above its surface. 



Acetite of potash gives a purple spark, flame coloured 

 and ramified on its surface, even when one crystal is placed 

 upon another. It is rendered luminous merely by taking 

 the spark from the conductor near it; and by exposure to 

 the shock it is beautifully phosphorescent, shining Avith a 

 green light, and is even superior in brilliancy to the sulphu- 

 rct of lime, though its light is of shorter duration than in 

 that preparation. This salt is extremely deliquescent, in 

 which state, and even when quite dissolved, it is still ren- 

 dered luminous by exposure to the light of the explosion. 



Soda. Sub-carbonate of soda affords a hissing purple 

 spark, flame coloured on its surface. It is phosphorescent 

 by the shock. 



Sulphate 



