SECT. ii. ELECTRIC DISCHARGED 



lig. 2. 



81 



If a vacuum tube with or without wires or tin coat- 

 ings be laid upon the induction coil of a battery, or 

 upon the prime conductor of an electrifying machine, 

 stratifications are produced by induction which are 

 divided by a magnet. Thus there are two distinct 

 forms of the stratified discharge, one direct, the other 

 induced. 



When Professor Pliicker of Bonn sent an induced 

 current of electricity from Buhmkorff's coil through a 

 vacuum tube having a platinum wire fused into each 

 extremity, and extending a little way into the interior 

 of the tube, electric light radiated from every point of 

 the negative wire, and when exposed to the action of 

 an electro-magnet the whole tube was filled with a 

 luminous atmosphere. But when all the negative 

 platinum wire except its extreme point was insulated 

 by a coating of glass, the rays of electric light which 

 radiated from the point were united into one single and 

 perfectly regular magnetic curve, upon the approach of 

 an electro-magnet; when the negative platinum wire 

 was partially insulated by glass coating, electric light 

 emanated from every exposed part, and assumed the 

 form of magnetic curves under electro-magnetic action. 

 Whence Professor Pliicker concluded that the luminous 

 atmosphere in the first experiment was the locus of an 

 infinite number of magnetic curves, and consequently 



VOL. I. G 



