328 M. Poisson on the Theory of Magnetism in Motion. 



lomb, by no means affects his claim to the discovery of the 

 general fact that all bodies, whether organic or inorganic, are 

 susceptible of becoming magnetic. Coulomb's explanation 

 may be right, or it may be wrong, and it is one of those opi- 

 nions which are not likely to be overturned by experiment ; 

 but were it proved to be erroneous, his discovery remains as 

 much his own as if he had never attempted to explain it. M. 

 Biot has distinctly stated, in the page already quoted, that the 

 phenomena may not really be magnetic ; that other circum- 

 stances may develope forces similar, or analogous to those of 

 electricity by contact ; and that the magnetic action experien- 

 ced by needles of all substances made use of by Coulomb, 

 may be owing to some small force which is yet unknown 

 to us. 



Professor Hansteen of Christiania, whose important magne- 

 tic researches we have frequently communicated to our read- 

 ers, has drawn from numerous experiments and observations 

 the important conclusion, that every vertical object, of what- 

 ever material it is composed, has a magnetic south pole 

 above, and a north pole below. This curious fact we had oc- 

 casion to publish, for the first time, in the Edinburgh Philo- 

 sophical Journal for January — April 1821. 



Art. XXV. — Abstract of' a Memoir on the Theory of Mag- 

 netism in Motion.* By M. Poisson. 



At the sitting of the Academy of Sciences of Paris held on 

 the 10th July last, M. Poisson communicated his Memoir 

 on the Theory of Magnetism in Motion. 



This celebrated mathematician, who had long ago given a 

 formula representing all the phenomena in magnetism as then 

 known, has undertaken the same task for the new facts ob- 

 served by M. Arago and others. 



Besides the effects produced in the interior of bodies by the 

 austral and boreal magnetic fluids, when they are in a state of 

 rest, there are others which are the result of the same fluids 

 in motion. The first take place when the external forces, 

 which separate the fluids from one another in the small spaces 



* Abstracted from Le Globe, No. 87. 



