]j4j OIi THE PHOSPHORESCENCE OF BODIES* 



as they discover to us a whole class of bodies devoid of the 

 least phoxphorescency, after exposure to electric light, they 

 may be deemed of some importance, especially as being one 

 step towards leading us to a theory of this phenomenon. I 

 trust you will be kind enough to send them to Mr. Nichol- 

 son, to be inserted in his extremely useful Journal. 



Combustibles. 



Habitudes of Sulphur. 1st, Roll brimstone gives no spark, and 'm 



bodies as to the scarcely at all luminous bv the shock. 2d, Flowers of sulphur 

 electric spark . , , . . l 



and the pro- are not phosphoric. 3a, A native specimen pure gave no 



spark, and was very slightly luminous by the shock. 4th, 



A native specimen mixed with carbonate of lime gave no 



spark, but was more luminous than the preceding specimens. 



Phosphorus inflames both by the spark and shock. 



Charcoal. Some kinds afford very good sparks, are phos- 

 phorescent upon the surface, and when the rods rest upon 

 them the dust is dispersed by the explosion, in the forms of 

 a luminous cloud. But other pieces, which were tried, did 

 not become phosphoric by exposure to the electric light* 



Coke gives a good spark, but is not luminous by the shock* 



Cannel coal and common Sunderland coal give sparks 

 beautifully variegated in minute spangles radiated upon its 

 surface, but they are not phosphoric. Welsh coal gives 

 similar sparks, but not so beautiful as the above; and is not 

 luminous by the shock. 



Peat, hard and dry, affords a very good 9park, but is 

 scarcely luminous. 



Soft, porous, very light peat, termed in this neighbour- 

 hood Ramsay turf, is not luminous except in the track of the 

 discharge, and even then it is extremely evanescent. 



Charred peat affords a very good spark, and is slightly 

 luminous. 



Bitumen, hard and brittle, of a dark brown colour, from 

 Derbyshire, gives no sparks* but the fluid spreads uniformly 

 and silently over its whole surface, to pass from the conduce 

 tor to the knob of the discharger held above it, with an ap- 

 pearance similar to the electric light in an exhausted receiver. 

 It is luminous by the shock, as is also the elastic bitumen 

 from the same country. 



Jet 



duction of 

 phosphores- 

 cence. 



Sulphur. 



Phosphorus. 



Charcoal. 



Coke. 

 Cannel coal. 



Peat. 



JBHumeri. 



