ELECTRICAL EXPERIMENTS. 



11 



Sulphate of soda gives a purple spark, and is luminous Alkali and at 

 , * , . ° kaline salts. 



by the shock. 



Nitrate of soda is not at all luminous, even when the 

 points of the discharging rods are in contact with it, during 

 the explosion. 



Muriate of soda. Several native specimens of diiFerent 

 colours were tried, and gave only a small stream of electric 

 light, almost without any sound. They were all luminous 

 by the shock, as was also common culinary salt. 



Fhosphate of soda affords only a purple hissing stream^ 

 but is luminous by the shock, though in a less degree than 

 the sub-carbonate. 



Sub-borate of soda. 1st. Tincal gives a purple hissing 

 spark, apparently proceeding from a red point upon its sur- 

 face. It is but slightly luminous by the shock. 2nd. Fast 

 Indian borax gives no spark, but the electric fluid glides si- 

 lently over every part of its surface from the conductor to 

 the knob of the discharger. Its phosnhorescency by the 

 shock is superior to tincal, but not equal to the refined bo- 

 rax of the shops. 3rd. Refined borax affords a hissing pur- 

 ple spark, sometimes flame coloured upon its surface; but 

 when a large piece is placed on the conductor it allows only 

 a purple stream to be drawn from it. It is luminous when 

 4he explosion is made above if, but when the shock is passed 

 through it) the phosphoric appearance is very brilliant and 

 has a greenish tint, the light is of short continuance, and 

 the salt is shattered to pieces. 



Ammonia. Aqua ammonia? of the shops is not luminous. 

 Carbonate of ammonia affords a dense purple spark, ra- 

 diated on its surface. It is very luminous with a white light, 

 when the shock is taken above it ; but it possesses a delicate 

 blue or rather purple tint, when the rods rest upon its sur- 

 face, and it is shattered into luminous pieces when the shock 

 is passed through it. 



Sulphate of ammonia <nves a purple hissing stream and is 

 luminous by the shock. 



Nitrate of ammonia i? not at all luminous when properly 

 prepared and crystallized ; but it is slightly phosphoric when 

 prepared with the common aqua fortis of the shops, and 

 not carefully crystallized. 



Muriate 



