168 



Intelligence and Miscellaneous Articles. 



This was not so ; the quantity of heat disengaged in this thermo- 

 rheometer was always represented by the formula Krl^ 2 , at least 

 when the breaks were rapid enough, just as if each section of the cur- 



I' 



rent had a real constant intensity — ; l\ was determined by the special 



action of the coil according to new laws, which are not those of Ohm. 

 This is shown by the following Table, obtained as the result of 

 experiments where a coil was interposed in the circuit. 



Table II. — Values of K with a Coil in the Circuit. 







a — 



1. 





0-5. 



Inten- 

 sity l\. 



Resist- 

 ance r. 













K Ca 





rl\ 2 





25-46 



c. 



rl' x 2 



C. 



9 



440 



0-20 



647 



019 



925 



23-88 



350 



17 



755 



017 



9-92 



21-04 



376 



0-18 



845 



0-21 



11 00 



18-44 



381 



017 



1039 



023 



12 52 



1578 



466 



018 



915 



018 



1390 



1315 



426 



018 



997 



0-21 



1565 



10-57 



427 



016 



970 



018 



18-70 



7-86 



476 



017 



1014 



019 



22-50 



5-29 



467 



016 



965 



017 



23-83 



3-37 



289 



015 



791 



0-20 



25 95 



1-81 



265 



0-21 



611 



0-25 







Means... 



018 





019 



But if there is no change in that portion of the circuit which is made 

 up of the thermorheometer (that is, in the portion where there is no 

 induction), all is modified in the coil ; and if its resistance is R, the 

 heat there produced is far more than that calculated by the formula 



KRI' 2 



• The law has therefore been changed during the induction 



a, 

 of a current upon itself in that portion of the circuit where this in- 

 duction takes place ; but it is only changed in this portion. We 

 shall, before long, investigate this change. 



We may be permitted to advert to a claim of priority which 

 M. Le Roux has made. 



M. Le Roux published in 1857 some purely theoretical ideas, ac- 

 cording to which a fragment of a current would meet in every por- 

 tion of the conductor a resistance greater than the statical resistance 

 which Ohm's laws assign to this conductor ; and in our prece- 

 ding experiments he has seen a confirmation of his ideas. 



We are the more at a loss to understand this reclamation because 

 our formulae are in entire disagreement with those of M. Le Roux, 

 and because, far from having justified his theory, we think we have 

 proved that it has no foundation. 



In this investigation we prove that the basis of his reasoning is 

 inexact, and that a broken current acts in a rectilinear circuit like 

 a continuous current. True, things are far more complex in a coil ; 

 but that is a case of pure induction, as Helmholtz has proved. 

 — Comptes Rendus, March 22, 1869. 





