M. Ampere on a ne'jo Eledro^dijnamic Experiment. 373 



one direction only, and the movement of continuous rotation 

 is a necessary consequence of it. It is useless to add, that if 

 the actions exerted by the horizontal conductor upon the two 

 portions of the moveable conductor (which I have just men- 

 tioned) force it to turn in opposite directions, it is because the 

 current from this last conductor cannot approach that of the 

 horizontal conductor in one of those portions without diverg- 

 ing from it in the other, and vice versa. However, as the 

 manner in which I have established the relation 



2 k -[- 11 = I 

 was not, perhaps, sufficiently rigorous, as I had verified it 

 only on a describing current, either an entire or a semi-cir- 

 cumference, whereas it ought to have been done upon each 

 clement of the circular horizontal current, I have therefore 

 produced another instrument, by which the same relation be- 

 tween n and k may be obtained in a more simple manner, 

 and the inconvenience which I have just spoken of is avoided; 

 because the experunent which I make with that instrument 

 proves at once that the action of a complete circuit on an ele- 

 ment of the electric fluid is always perpendicular to the dii-ec- 

 tion of this element, which is sufficient to demonstrate that 

 2k + n = 1 , as I shall show in a note which I intend to pub- 

 lish shordy, and where the description of the instrument here 

 presented will be found. 

 Paris, Aug. 16th, 1825. 



LX. Memoir on a ne'w Electro-dyiiamic Experiment, on its 

 Application to the Formula representiiig the mutual Action of 

 the tiao Elements of Voltaic Coiidiictors, and on some new 

 Results deduced from that Formtda. By M. Ampere.* 



THE manner in which I have determined the relation be- 

 tween the two co-efficients of the formula by which I 

 represented the mutual action of the two elements of electric 

 currents, in the memoir which I read before the Academy on 

 the 10th of June 1822, being liable to some difficulties, I have 

 endeavoured to establish this relation in a more simple and 

 direct manner. I succeeded in this very easily by means of 

 an instrument which I shall first describe ; 1 will then present 

 some new results which I have deduced from this formula. 

 On a stand TT Plate I. (fig. 3) in the shape of a table, two 



• From the Annales de Chimie et dc Physique, torn. xxix. p. 381. This 

 memoir was read at the Royal Academy of Sciences of Paris, at the sitting 

 of the 1 2th of September last. 



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