340 [Dec. 18, 



electroscope denotes the evidence of tension before the circuit is 

 completed. 



In my former communications to the Royal Society I have alluded 

 to the direction of a force in the induction discharge from the positive 

 towards the negative (Phil. Trans. 1858, p. 16, sections 57, 58). 



In 1859 I observed that there was also a tendency or indication 

 of a force emanating from the negative wire (Phil. Trans. 1859, 

 pp. 140, 142, 153, sections 68, 72, 99) ; the actual disruption of the 

 particles from the negative terminal also indicates a force ; and this 

 disruption is as freely obtained by the continuous discharge of the 

 battery ( 16) as it is by the intermittent discharge of the induction 

 coil. 



I have always observed that with the lowest state of intensity 

 with which the discharge can be obtained from an induction coil, the 

 striae are wider apart and the dark space between the positive and 

 the negative is much extended ; under some conditions of the dis- 

 charge it is the negative, and not the positive, that assumes the domi- 

 nant character. 



The form of the striae in the battery discharge, as observed in 

 No. 315, figs. 7, 8, and 9, presents an appearance somewhat analo- 

 gous with the stationary undulations which exist in a column of air 

 when isochronous progressive undulations meet each other from op- 

 posite directions, and on the surface of water by mechanical impulses 

 similarly interfering with each other. 



May not the dark bands be the nodes of undulations arising from 

 similar impulses proceeding from positive and negative discharges? 



Or can the luminous stratifications ivhich we obtain in a closed 

 circuit of the secondary coil of an induction apparatus, and in the 

 circuit of the voltaic battery, be the representation of pulsations which 

 pass along the wire of the former and through the battery of the 

 latter, impulses possibly generated by the action of the discharge 

 along the wires ? 



