FARADAY 



no attraction, as you will observe if I bring 1 a little iron 

 filings or nails near the iron. But now, if I make contact 

 with the battery, they are attracted at once. It becomes 

 at once a powerful magnet, so much so that I should not 



wonder if these mag- 

 netic needles on- dif- 

 ferent parts of the 

 table pointed to it. 

 And I will show you, 

 by another experi- 

 ment, what an attrac- 

 tion it has. This piece and that piece of iron, 

 and many other pieces, are now strongly attracted 

 (Fie. 52) ; but, as soon as I break contact, the 

 power is all gone, and they fall. What, then, can 

 FlG - 52 be a better or a stronger proof than this of the re- 

 lation of the powers of magnetism and electricity? Again: 

 here is a little piece of iron which is not magnetized. It will 

 not, at present, take up any one of these nails ; but I will take 

 a piece of wire and coil it round the iron (the wire being 

 covered with cotton in every part 

 it does not touch the iron), so that 

 the current must go round in this 

 spiral coil; I am, in fact, prepar- 

 ing an electro-magnet (we are 

 obliged to use such terms to ex- 

 press our meaning, because it is a 

 magnet made by electricity be- 

 cause we produce by the force of 

 electricity a magnet of far greater 

 power than a permanent steel one). 

 It is now completed, and I will re- 

 peat the experiment which you saw 

 the other day, of building up 

 a bridge of iron nails: the con- FlG> 53 



tact is now made and the current is going through ; it is now 

 a powerful magnet ; here are the iron nails which we had the 

 other day, and now I have brought this magnet near them 

 they are clinging so hard that I can scarcely move them with 

 my hand (FiG. 53). But when the contact is broken, see how 



