THE 

 LONDON, EDINBURGH and DUBLIN 



PHILOSOPHICAL MAGAZINE 



AND 



JOURNAL OF SCIENCE. 



[THIRD SERIES.] 



FEBRUAR Y 1849. 



X. Experiments on Diamagnetism. By H. C. QErsted*. 



A T a meeting of the Royal Society of Sciences at Copen- 

 ■^*- hagen on the 30th of June, I communicated the results 

 of some researches I had mnde upon diamagnetism, an abs- 

 tract of which appeared in the proceedings of the Society. 

 During the vacation I have continued my experiments, and 

 have obtained several new results. As the memoir will not 

 appear for many months, I have decided on giving an abstract 

 which may be communicated to my distant friends. 



My researches relate to the celebrated diamagnetic disco- 

 veries of Mr. Faraday, and to the extensions they have re- 

 ceived from some learned Germans. 



Mr. Faraday, in the experiments with his great electro- 

 magnet, met with a class of bodies which are repelled by the 

 two poles of the magnet. One or two examples of this repul- 

 sion had been known for some time ; but the researches of 

 the illustrious Englishman has rendered this fact general, and 

 of such importance as to become the object of attention of all 

 philosophers. Brugmanns had already discovered in 1778 

 that bismuth is repelled by the two poles of a magnet. Bec- 

 querel, sen., again met with this repulsion both in bismuth 

 and in antimony. Mr. Faraday found that his great electro- 

 magnet produced this repulsion in almost all the bodies it did 

 not attract. He discovered at the same time that long pieces 

 thus repelled, assume, under the influence of the electro- 

 magnet, a position perpendicular to that which an attracted 

 body would take under the same circumstances. This pro- 

 perty he called diamagnetism. 



M. Reich of Freiburg fj so well known from his beautiful 

 experiments on the deviation in the fall of bodies from a great 



* From the Annates de CMmie et de P/it/sique for December 1848. 

 t See p. 127 of the present Number. 

 P/iil. Mag. S. 3. Vol. 34.. No. 227. Feb. 1849. G 



