Magnetic Characters of MetaU^ §fc, 73 



this field of research, we are necessarily led to infer that the 

 subject has not yet been accurately and satisfactorily deter- 

 mined. 



9. The beautiful experiments of M. Arago, and the final 

 development of magnetic electricity by Dr Faraday, afford 

 an ample explanation of nearly all those experiments in 

 which vibrations of the magnetic needle, near the bodies un- 

 der examination, were taken as evidence of their magnetic 

 actions ; as well as in all those cases in which light needles 

 of the bodies examined were vibrated under the influence of 

 powerful magnets. It is reasonable to suppose, also, that 

 thermo-electric currents would influence the results of 

 those experiments which were made previous to the discovery 

 of that branch of electricity by Dr Seebeck, especially in those 

 cases in which the bodies under examination were held in the 

 hand whilst presented to the magnetic needle. 



10. There are, however, some phenomena on record, the 

 explanations of which do not appear to fall within the range 

 of the laws either of magnetic- electricity or thermo-electri- 

 city ; and, therefore, the cause of their development is neces- 

 sarily located in some other source. For instance, when 

 Coulomb employed light, delicately suspended needles of 

 gold, silver, glass, wood, and other substances, both organic 

 and inorganic, he found them obey the polar forces of a mag- 

 net in precisely the same manner as needles of iron would 

 do ; for, after the vibrations had ceased, those needles be- 

 came arranged between the north and south poles of power- 

 ful magnets, in such manner, that their axis rested in the 

 line of magnetic force, or in a right line joining the mag- 

 netic poles employed. 



11. It is somewhat remarkable that, when similar experi- 

 ments were made by M. Becquerel, the results were very 

 different. By employing needles of wood, lac, and some 

 other substances, this philosopher found that the positions 

 they assumed when at rest directly between the north and 

 south poles of powerful magnets, were invariably at right 

 angles to a right line joining those poles ; and, consequently, 

 at right angles relative to the magnetic forces, or to the 

 position in which the needles of Coulomb rested. From the 



