Galvanism, from Galvani to Ohm. 85 



closed instead of open, and to inquire whether any effect is 

 produced on a magnetic needle when an electric current is 

 passed through a neighbouring wire. At first he placed the 

 wire at right angles to the needle, but observed no result. 

 After the end of a lecture in which this negative experiment 

 had been shown, the idea occurred to him to place the wire 

 parallel to the needle : on trying it, a pronounced deflexion was 

 observed, and the relation between magnetism and the electric 

 current was discovered. After confirmatory experiments with 

 more powerful apparatus, the public announcement was made 

 in July, 1820 * 



Oersted did not determine the quantitative laws of the 

 ;action, but contented himself with a statement of the qualita- 

 tive effect and some remarks on its cause, which recall the 

 magnetic speculations of Descartes : indeed, Oersted's concep- 

 tions may be regarded as linking those of the Cartesian school 

 to those which were introduced subsequently by Faraday. " To 

 the effect which takes place in the conductor and in the sur- 

 rounding space," he wrote, " we shall give the name of the 

 -conflict of electricity? " The electric conflict acts only on the 

 magnetic particles of matter. All non-magnetic bodies appear 

 penetrable by the electric conflict, while magnetic bodies, or 

 rather their magnetic particles, resist the passage of this conflict 

 Hence they can be moved by the impetus of the contending 

 powers. 



" It is sufficiently evident from the preceding facts that the 

 electric conflict is not confined to the conductor, but dispersed 

 pretty widely in the circumjacent space. 



" From the preceding facts we may likewise collect, that this 

 conflict performs circles ; for without this condition, it seems 

 impossible that the one part of the uniting wire, when placed 

 below the magnetic pole, should drive it toward the east, and 

 when placed above it toward the west; for it is the nature of a 



* Schweigger's Journal fur Chemie und Physik, zxix (1820), p. 275 ; Thomson's 

 Annals of Philosophy, xvi (1820), p. 273; Ostwald's Klattiter der 

 ' Wi.ssenseha.ften, Nr. 63. 



