NOMOS. 55 



instance, does not move along the current beyond a 

 certain point, but it presently escapes as gas. Its affi- 

 nities for the platinum, and those of the platinum for 

 it, are not sufficient to cause it to traverse the metal, 

 And so also, in the experiments where the discharge 

 is made across an exhausted receiver, or a receiver 

 full of nitrogen, and where the metallic particles 

 collect upon the inner surface of the glass, the affinities 

 between these particles and those of the glass are not 

 sufficiently marked to cause the former to traverse 

 the latter. These metallic particles escape out of 

 the circuit for the same reason and almost in the 

 same way as did the hydrogen. There are interrup- 

 tions, then, to the continuous propagation of chemi- 

 cal action around the circuit, and what the effects of 

 these interruptions must be, it is not easy to say. They 

 must certainly diminish the amount of action, but 

 on the other hand they may be necessary to give 

 rise to the phenomenon called tension. 

 Without this retardation of the current, o/th^ph^o- 

 indeed, the motion might be so rapid as to menon called 



& -ill tension. 



escape our notice. We might only be 

 conscious of chemical changes effected instantly 

 and as by magic, and we might have been alto- 

 gether ignorant of the process which we call elec- 

 tricity. 



There are, however, many facts which remain to 

 be considered before we can hope to be able to answer 

 the question, proposed at the outset of the inquiry 

 what is electricity ? We have spoken of certain 

 molecular movements, but we have not yet attended 



E 4 



