43 Electro- Magnetic Experiments, 



terminate length, and those of magnets ; after that I had deter- 

 mined, bv a comparison of the results of experiment with those 

 of calcvihition, the law of the attraction and repulsion of two infi- 

 nitely small portions of electric currents. I stated in this memoir 

 all the differences which are established between the attractions 

 and repulsions of electric currents, and those of ordinary electri- 

 city, amounting not only to a dissimilarity, but almost to a com- 

 plete opposition. 



Sitting of the 1 5th of October. 



I read a note relative to the interesting experiments of M. Arago, 

 on the magnetising of steel by means of a current, produced by a 

 Voltaic pile. The object of this note was to show, that all the 

 circumstances of that actioii of electric currents, were conformable 

 with what I had announced on the identity of these currents, and 

 of those which I admit in magnets, and may be regarded as com- 

 pleting the demonstration of it. 



Sitting of th« 30th of October. 



I announced to the Academy that, conformably to my theory 

 of the phenomena which the electric and magnetic currents pre- 

 sent, the action of the earth would lead in a plane perpendicular 

 to the direction of the inclination of the needle, the |)lane of a 

 moveable portion of the conductor of a Voltaic pile, so disposed 

 as to form a circuit nearly closed. I described two sorts of ap- 

 paratus, the first of which had served me to produce the move- 

 ment of a conjunctive wire, corresponding to the direction of the 

 needle of a compass, in the horizontal plane corresponding with 

 the line of declination ; and the other, that which corresponds to 

 the direction of the inclination of the needle in the plane of the 

 magnetic meridian. I exhibited at the same sitting an instru- 

 ment, by which there may be turned in a horizontal plane a por- 

 tion of electric current, the conductor of which is attached to a 

 vertical pivot by the action of another current, an action which 

 conducts it into the situation where these two currents are pa- 

 rallel, and in the same direction. 



Sitting of the Gth of November. 



1 communicated to the Academy a fact relative to the actioii 

 of conductors twisted iti spirals ; a fact which I had observed a 

 long time before t discerned the cause of it, which M. Arago had 

 also observed, and whence I deduced — 



1st. A very simple means of neutralising the longitudinal ef- 

 fect of an electric current in a conductor twisted spirally, and of 

 reducing the action of it to the transversal effect, which would 

 then be perfectly identical with that of a magnet. 



2d. 



