56 DR. FARADAY'S EXPERIMENTAL RESEARCHES IN ELECTRICITY. 



produced by the making and breaking contact, and their separation by an inter- 

 mediate and indifferent state, this separation is probably more apparent than real. 

 If the conduction of electricity be effected by vibrations, or by any other mode in 

 which opposite forces are successively and rapidly excited and neutralized, then we 

 might expect a peculiar and contrary development of force at the commencement and 

 termination of the periods during which the conducting action should last (somewhat 

 in analogy with the colours produced at the outside of an imperfectly developed solar 

 spectrum) : and the intermediate actions, although not sensible in the same way, may 

 constitute the very essence of conductibihty. It is by views and reasons such as these, 

 which seem to me connected with the fundamental laws and facts of electrical science, 

 that I have been induced to enter, more minutely than I otherwise should have done, 

 into the experimental examination of the phenomena described in this paper. 



1116. Before concluding, I may briefly remark, that on using a voltaic battery of 

 fifty pairs of plates instead of a single pair (1052.), the effects were exactly of the 

 same kind. The spark on making contact, for the reasons before given, was very 

 small (1101. 1107.); that on breaking contact, very excellent and brilliant. The 

 continuous discharge did not seem altered in character, whether a short wire or the 

 powerful electro-magnet were used as a connecting discharger. 



1117. The effects produced at the commencement and end of a current, (which are 

 separated by an interval of time when that current is supplied from a voltaic appara- 

 tus,) must occur at the same moment when a common electric discharge is passed 

 through a long wire. Whether, if happening accurately at the same moment, they 

 would entirely neutralize each other, or whether they would not still give some defi- 

 nite peculiarity to the discharge, is a matter remaining to be examined ; but it is 

 very probable that the peculiar character and pungency of sparks drawn from a long 

 wire depend in part upon the increased intensity given at the termination of the dis- 

 charge by the inductive action then occurring. 



1118. In the wire of the helix of magneto-electric machines, (as, for instance, in 

 Mr. Saxton's beautiful arrangement,) an important influence of these principles of 

 action is evidently shown. From the construction of the apparatus the current is per- 

 mitted to move in a complete metallic circuit of great length during the first instants 

 of its formation : it gradually rises in strength, and is then suddenly stopped by the 

 breaking of the metallic circuit ; and thus great intensity is given by induction to the 

 electricity, which at that moment passes (1064. 1060.). This intensity is not only 

 shown by the brilliancy of the spark and the strength of the shock, but also by the 

 necessity which has been experienced of well insulating the convolutions of the helix, 

 in which the current is formed ; and it gives to the current a force at these moments 

 verj' far above that which the apparatus could produce if the principle which forms^ 

 the subject of this paper were not called into play. 



Royal Institution, 

 December 8th, 1834. 



