74 W. Sturgeon, Esq., on the 



results afforded by the experiments of M. Becquerel, that 

 philosopher has been led to consider that the effects pro- 

 duced by a strong magnet on a magnetic needle, or on soft 

 iron, differ essentially from those which take place in all 

 bodies whose original magnetism is very weak. In the for- 

 mer the magnetic axis of each is arranged in its length ; but 

 in the latter class of bodies the magnetic axis becomes ar- 

 ranged transversely. M. Becquerel shews, however, that 

 wooden needles assume different positions, with respect to 

 the magnetic poles, according to the distance at which they 

 are placed from them.* 



12. In a paper by Dr Faraday, read before the Royal So- 

 ciety of London in January last, it is stated, that a variety 

 of bodies, bismuth being the most eminent in this respect, 

 arrange themselves with regard to powerful magnetic poles, 

 in precisely the same manner as described by Becquerel ; 

 that is, with their longest axis at right angles to the line of 

 magnetic force. 



13. Dr Faraday has attempted a classification of a great 

 number of bodies under the two following heads : — Magnetics 

 and Diamagnetics. The former class, of which iron is the 

 grand type, become arranged, whilst under magnetic influ- 

 ence, with their longest axis in the magnetic line of force ; 

 and the latter class, of which bismuth is the type, become 

 arranged at right angles to the magnetic line of force. In 

 the magnetic class, Dr Faraday places some of those bodies 

 which, according to M. Becquerel's nomenclature, would be 

 placed in the other class, or amongst those which become 

 arranged at right angles to the line of magnetic force. Such, 

 however, is the condition of this interesting inquiry at the 

 present time, no two of those hitherto engaged in it having 

 arrived at sim.ilar results in any series of experiments that 

 have been undertaken. 



14. The inquiries that I have made in this department of 

 magnetics have been conducted partly by the employment 

 of magnetic needles, partly by permanent steel magnets, and 



* Traits Experimental de l'Electricit6 et du Maguetisme, tome ii., p. 387. 



