856 



were at a distance not less than an inch, these metals pointed axially. 

 When the battery power was somewhat increased and the poles 

 brought nearer to each other, instead of the metal being more strongly 

 attracted, it became less sensible to either attraction or repulsion, 

 becoming very sluggish in its motions ; but when the magnet was 

 well-excited and the polar terminations brought within a quarter of 

 an inch of each other, most of those metals pointed decidedly equa- 

 torially, and were repelled as dia-magnetics. 



The author found that the phenomencm of revulsion, described by 

 Faraday and more particularly noticed by him in copper, was exhi- 

 bited in nearly all metals which are less magnetic than platinum, or 

 less dia-magnetic than antimony, and noticed that the direction of 

 the revulsive motion is different in magnetic and in dia-magnetic 

 metals. He also noticed that in metals, whether pure or compound, 

 which changed from the magnetic to the dia-magnetic state, the di- 

 rection of the revulsion changed. 



Experiments are next described which were instituted for the 

 purpose of ascertaining the order in which different metals are af- 

 fected magnetically or dia-magnetically. 



Phenomena are also described which present themselves when 

 the polar terminations are from 0*25 inch to 0*1 inch apart, and 

 a disc of metal is so suspended that one-half of it is between 

 and the other half beyond these terminations. If the metal be 

 amongst those classed as magnetic, or be magnetically affected by 

 the power employed, it is attracted, and after the first motion has 

 subsided, clings to one of the polar pieces ; if the metal be dia-mag- 

 netic, it is repelled and in many instances driven entirely out from 

 between the poles. At the instant of the completion of the voltaic 

 circuit, the disc of metal moves transversely, with a tendency to pass 

 outwards from between the poles ; and on breaking the circuit, the 

 disc moves transversely in the contrary direction. The directions of 

 these transverse motions are alike in all metals which do not become 

 so strongly attracted by the magnetic influence as to cling firmly to 

 one of the polar terminations, being in the same direction with pla- 

 tinum and palladium as with antimony and bismuth ; but they are 

 exhibited with greatest force by those metals which decidedly show 

 revulsion. 



The author makes various hypothetical assumptions in order to 

 explain the phenomena he has described ; and, in conclusion, states 

 his opmion, "that the metals which have been observed to change 

 from the magnetic to the dia-magnetic state are subject to three dif- 

 ferent conditions of molecular arrangement : the first, one of mag- 

 netic polarity, and which on its cessation only induces a feeble elec- 

 tric current ; the second, the intermediate or sluggish state, in which 

 the metal is not polarized so as to be either attracted or repelled by 

 the magnet, but in which there is nevertheless so great a molecular 

 disturbance that very powerful electric currents are induced on its 

 discontinuance ; and the third, in which the particles are so polarized 

 as to be repelled by the poles of the magnet which has induced such 

 condition, but which last condition does not, on its discontinuance, 

 induce powerful electric currents." 



