1884.] Mr. WillougJihy Smith on Electric Induction. 119 



WEEKLY EVENING MEETING, 

 Friday, June 6, 1884. 



Waeren De La Eue, Esq. M.A. D.C.L. F.R.S. Manager and 

 Vice-President, in the Chair. 



WiLLOUGHBY Smith, Esq. M.B.I. 



Volta-Electric and Magneto-Electric Induction. 



Tbe subject which I shall bring before your notice this evening is 

 " \olta-Electric and Magneto-Electric Induction " ; and I propose to 

 describe some of my experiments in connection with this phenomenon 

 in dectricity and magnetism, which was discovered, named, and for 

 fortr years fostered within this very building by our universally 

 esteemed and beloved Michael Faraday. 



It is now thirty years ago that Faraday gave me my first lesson in 

 Voltt-Electric Induction, at the same time impressing upon me the 

 fact taat physical science must ever be progressive and corrective, and 

 that hs was always pleased to learn that his experiments had been 

 repeated by others, with a view to their verification or correction. In 

 the remembrance of this, I have felt encouraged in coming before you 

 this evening. 



Doubtless all present are familiar with the fact, that about 1819 

 Professor Oersted made a discovery which has done much to advance 

 our knowledge with regard to electricity and magnetism. This 

 disccvery arose from a very simple experiment, but it is none the less 

 valuable on that account. I will now repeat this experiment, as the 

 result obtained will lead up to, and enable you to better understand 

 what I nay show later on. Here is a length of copper wire, from the 

 top surfac^e and centre of which projects a metal pin, having, balanced 

 on its point, a magnet. The position of the steel magnet is, as you 

 perceive, parallel with the wire ; and that position being north and 

 south, it will thus remain until, by pressing down this spring, the 

 length of copper wire is placed in metallic circuit with this battery, 

 and you observe that the magnet immediately has a tendency to place 

 itself at right angles to the copper wire, remaining thus displaced 

 until the current ceases to flow, when the needle again obeys the 

 influence of terrestrial magnetism, and returns to its former position. 

 This was Oersted's exjDeriment which led to the discovery that all 

 bodies possess the qualities of a magnet whilst a current is passing 

 through them. From this fact Faraday conceived the idea that, if a 

 similar length of copper wire were placed parallel with the former 



