Electro-Magnetism, as a Moving PoiDer. Ill 



the battery current in proportion to its velocity ; whereas the ap- 

 phcation of mechanical force to drive the machine against its 

 own motion, contributes to the magnetizing power of the bat- 

 tery. The same rule applies to the motion of repelling poles. 



When two repelling electro-magnets are made to approach each 

 other, a recession of the magnetic forces takes place, and conse- 

 quently a secondary current is developed flowing in the direction 

 of the battery current. While the forces are thus kept in re- 

 tirement, if the two magnets be made to recede, they will again 

 be determined towards the poles, and consequently the secon- 

 dary will flow against the battery current. By taking advan- 

 tage of these laws, I was led to the invention of a new instru- 

 ment (Magnetic Electric Multiplier, described in the last number 

 of this Journal,) in which, the secondary current may be so ap- 

 plied as to diminish or accelerate the velocity of the revolving 

 bar. 



It will now be readily seen, that two electro-magnets, with a sta- 

 tical repelling power sufficient to keep them asunder, would cease 

 to repel when the machine is in motion. The attractive forces 

 constitute the paramount motive power, and when the velocity 

 of the machine exceeds that which the repulsive powers alone 

 would give it, they are of no value whatever, unless they ope- 

 rate in conjunction with attractive forces ; but even where this is 

 the case, the secondary curreiit arising from the velocity of the 

 machine, must occasion so great a disparity between the similar 

 poles of the magnets which change and those which do not 

 change, that attraction, in lieu of repulsion, must take place. 



I have thus endeavored to point out the most important of 

 those difficulties in the way of the application of this power, 

 which necessarily arise from the connexion of galvanism and. 

 magnetism. There are many other hindrances entirely of a me- 

 chanical nature, which perseverance will doubtless overcome. 



