Connexion between Magnetism and Mecincity. SS**" 



i. If the extremes of a voltaic battery (we will suppose 

 it to consist of 20 pairs of 8 inch plates,) be connected by 

 a platinum wire, it becomes heated, and, if of safRciently 

 small diameter, it suffers ignition. Let us suppose such a 

 wire W, lying upon the supports P and N, which represent 



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w. 



7\ 



K 



the positive and negative conductors of the active Voltaic 

 apparatus, P being connected with the first zinc plate, and 

 N with the last copper plate ; upon bringing the north pole 

 of a common magnetic needle heloiv and at a right angle to 

 the platinum wire, it will be repelled or driven downwards ; 

 jf we now remove the needle keeping it in the same posi- 

 tion, so that its north pole may be above the platinum wire, 

 it will then be attracted towards it. If the electric poles be 

 reversed, these phenomena will also be reversed. 



If we suppose the conjunctive platinum wire to be vertic- 

 al, instead of horizontal, and in that position approach it 

 with either end of the magnetic needle, the needle will os- 

 cillate, but will not be permanently attracted or repelled by 

 any part of the conjunctive wire. — Professor Oersted. 



2. If a small steel bar be attached to the conjunctive 

 wire, and parallel to it, it does not become a polar magnet ; 

 but if it be attached transversely, it does become polar, and 

 it becomes north and south, or south and north, according 

 to the direction of the supposed electric current traversing 

 the conjunctive wire, according as one or the other end of 

 it is positive or negative. Thus supposing W to represent 

 fhe platinum conjunctive wire of the Voltaic apparatus, and 



