270 



M. Wartmann's First Memoir 



16. From the preceding logarithms we should conclude, 

 that when the conducting wire of a current is connected with 

 another wire convolved in the form of a helix, its conducti- 

 bility measured by the intensity of the current which it is ca- 

 pable of inducing, varies for different portions of its length 

 according to a different law from that which it follows when 

 it only completes the circuit, admitting proportionality to 

 exist between the inducing and the induced current, as several 

 physicists suppose (e). 



17. In order to verify this conjecture, the copper wire was 

 placed parallel to the axis of the astatic needle, situated in the 

 plane of the magnetic meridian, and the maximum amplitude 

 of the arc traversed by this needle was observed, as well as 

 the value of its stable deviation, in the following different alter- 

 natives (the additional copper wire being united with the first 

 inductor wire to close the circuit of a pile of two elements) : — 



a. The circuit of the second inductor and that of the in- 

 duced wire both being closed. 



b. These two circuits being open. 



c. The one being shut, the other open. 



* This abnormal result is either an error of reading of the assistant, oc- 

 casioned by the smallness of the interval between the divisions of the dial, 

 or a heating of the wire under the influence of the current. 



