concerned in the Phenomena of ordinary Electricity, ^c. 37 



powerful permanent magnet over either end of the cylindi-ical rod, 

 the permanent and temporary magnets thus presenting conti-ary 

 poles to each other, ought by the neutrahzation of the opposite 

 states of electricity to cause the armature of that end to fall off. 

 On making the trial with a powerful horseshoe magnet the arma- 

 ture of that end, as might be expected, did fall. 



So far the result corresponded with the hypothesis; but if 

 electricity be really the agent, the transmission of a stream of 

 common electricity from the prime conductor of a large and 

 powerful cjdinder machine shoukl act like the permanent magnet 

 in detaching either of the pendent armatures from the ends of 

 the temporary magnet. On throwing a torrent of sparks, which 

 to the eye appeared a continuous stream of lire from a cylinder 

 capable at the moment of affording twelve-inch sparks, on the 

 temporary magnet, the pith-balls, hitherto of course unaffected, 

 diverged to a maximum, but the pendent armatures remained in 

 their places. 



It will be said by the supporters of the hypothesis in question, 

 that the quantity of voltaic electricity passing through the coated 

 copper wire, coiled round the cylindrical iron rod, was so nmch 

 greater than that furnished by the glass cylinder machine, that 

 the electrical state of the poles of the temporary magnet and of 

 the armatures was not destroyed, and hence the armatures were 

 still attracted. If this be so, it nmst be inferred, that as the 

 voltaic electricity of the pole of the temporary magnet was neu- 

 tralized by the opposite electricity of the permanent magnet when 

 approached, so ought it also to have been neutralized by the 

 stream of opposite electricity thrown in by the conductor of the 

 electrical machine. That the quantity of the frictional electricity 

 was sufficient for such a neutralization, was abundantly proved 

 by the maximum divergence of the pith-balls with the same 

 electricity as that of the prime conductor which supplied it. 

 Why then were not the laws of electricity obeyed ? Why did not 

 the armatures fall off as well as when the permanent magnet was 

 applied, if the agent in both cases were electricity ? 



Doubts founded on the foregoing objections, although they 

 may not have been expressed, seem to have influenced the 

 language of those who have alluded to the reaction of magnetism 

 and electricity; and we discover remarkable reserve amongst 

 writers and exj)erimenters on this subject, arising no doubt from 

 appreciation of the difficulty. Dr. lioget, in his excellent article 

 on Electro- magnetism*, thus expresses himself: — "At all events 

 we know that two currents of electricity in motion, impress by 

 their mutual action, a force differing very essentially from thcwc 

 commonly considered electric, and which affects the magnetic 

 * Encyclop. Melropolit,, par. 5ii, 



