SECT. ii. ON ELECTRIC DISCHARGES. 89 



emanated from the negative ball, while distinct luminous 

 flash discharges took place through the strise. Thus by 

 the amount of resistance introduced into the circuit, the 

 number of striae can be regulated, their position fixed, 

 separating or closing up the dark space between the 

 luminous glows round the balls. 



In these experiments there is indication of a force 

 emanating from the negative wire. The actual dis- 

 ruption of the particles from the negative terminal also 

 indicates a force, and the disruption is as freely ob- 

 tained by the continuous discharge of the battery, as it 

 is by the intermittent discharge of the induction 

 coil. Besides, when Mr. Gassiot sent discharges from 

 the induction coil through Torricellian vacua, he 

 several times observed that while a cloud-like dis- 

 charge issued from the positive terminal, a long tongue 

 of the most brilliant blue phosphorescent light ema- 

 nated from the upper part of the negative terminal, and 

 a brilliant white tongue of light was also seen close to 

 the negative wire : so there is reason to believe that force 

 emanates from both terminals. 



Some of the preceding striated discharges * present 

 an appearance somewhat analogous with the stationary 

 undulations (or nodes) which exist in a column of air 

 when isochronous progressive undulations meet one 

 another from opposite directions, and on the surface of 

 water by mechanical impulses similarly interfering with 

 each other.' 2 



6 May not the dark bands be the nodes of undulations 

 arising from similar impulses proceeding from positive 

 and negative discharges ? or can the luminous stratifi- 

 cations which we obtain in a close circuit of the 

 secondary coil of an induction apparatus, and in the 

 circuit of a voltaic battery, be the representations of 



2 Connection of the Physical Sciences.' 



