Reciprocating Magnetic ^^ttr action. 341 



as a new effect produced by one of the most mysterious agents of 

 nature, you will not, perhaps, think the following account of it un- 

 worthy of a place in the Journal of Science. 



It is well known that an attractive or repulsive force is exerted 

 between two magnets, according as poles of different names, or poles 

 of the same name, are presented to each other. 



In order to understand how this principle can be applied to pro- 

 duce a reciprocating motion, let us suppose a bar magnet to be sup- 

 ported horizontally on an axis passing through the center of gravity, 

 in precisely the same manner as a dipping needle is poised ; and 

 suppose two other magnets to be placed perpendicularly, one under 

 each pole of the horizontal magnet, and a little below it, with their 

 north poles uppermost ; then it is evident that the south pole of the 

 horizontal magnet will be attracted by the north pole of one of the 

 perpendicular magnets, and its north pole repelled by the north pole 

 of the other : in this state it will remain at rest, but if, by any means, 

 we reverse the polarity of the horizontal magnet, its position will be 

 changed and the extremity, which was before attracted, will now be re- 

 pelled ; if the polarity be again reversed, the position Will again be 

 changed, and so on indefinitely : to produce, therefore, a continued 

 vibration, it is only necessary to introduce, into this arrangement, 

 some means by which the polarity of the horizontal magnet can be 

 instantaneously changed, and that too by a cause which shall be put 

 in operation by the motion of the magnet itself; hovsr this can be 

 effected, will not be difficult to conceive, when I mention that, instead 

 of a permanent steel magnet, in the moveable part of the apparatus, 

 a soft iron galvanic magnet is used.* 



The change of polarity is pjoduced simply by soldering to the 

 extremities of the wires which surround the galvanic magnet, two 

 small galvanic batteries in such a manner that the vibrations of the 

 magnet itself may immerse these alternately into vessels of diluted 

 acid ; care being taken that the batteries are so attached that the 

 current of galvanism from each shall pass around the magnet in an 

 opposite direction. 



Instead of soldering the batteries to the ends of the wires, and 

 thus causing them at each vibration to be lifted from the acid by the 

 power of the machine ; they may be permanently fixed in the vessels, 



* For a method of constructing the galvanic magnet on an improved plan, see my 

 paper in Vol. XIX, p. 329 of this Journal. 



Vol. XX.— No. 2. 44 



