[ 287 ] 



XXXVIII. On the Identity of the Vibrations of Light with Elec- 

 trical Currents. By L. Lorenz*. 



THE science of our century has succeeded in demonstrating 

 so many relations between the various forces (between elec- 

 tricity and magnetism, between heat, light, molecular and che- 

 mical actions), that we are in a sense necessarily led to regard 

 them as manifestations of one and the same force, which, accord- 

 ing to circumstances, occurs under different forms. But though 

 this has been the guiding idea with the greatest inquirers of our 

 time, it has been by no means theoretically established; and 

 though the connexion between the various forces has been de- 

 monstrated, it has only been explained in single points. Thus 

 Ampere has theoretically explained the connexion between elec- 

 tricity and magnetism, though he has not furnished a proof of 

 the possibility of the peculiar molecular electrical currents (as- 

 sumed by him) which in virtue of their ow r n power are conti- 

 nuous ; and, in like manner, Melloni w T as subsequently led step 

 by step to the assumption of an identity of light with radiant 

 heat. These theories are, however, quite isolated members of 

 the great chain ; and so far are we from being able to follow 

 out theoretically the idea of the unity of force, that even now, 

 half a century after (Ersted's discovery, the two electricities are 

 regarded as electrical fluids, light as vibrations of cether, and heat 

 as motions of the molecules of bodies. 



Yet these physical hypotheses are scarcely reconcileable with 

 the idea of the unity of force ; and while the latter has had a 

 signal influence on science, this can by no means be said of the 

 former, which have only been useful inasmuch as they furnish 

 a basis for our imagination. Hence it would probably be best 

 to admit that in the present state of science we can form no con- 

 ception of the physical reason of forces and of their working in 

 the interior of bodies ; and therefore (at present, at all events) 

 we must choose another way, free from all physical hypotheses, 

 in order, if possible, to develope theory step by step in such a 

 manner that the further progress of a future time will not nullify 

 the results obtained. 



This idea is at the basis, not only of the present investigation, 

 but also of my earlier researches on the theory of light f; and I 

 am the more moved to adhere to it, that it shows in a remark- 

 able manner how the results which I venture here to develope 

 attach themselves to those I have formerly obtained, and go 

 hand in hand with them. At the same time that I keep the in- 

 vestigation free from all physical hypotheses, I shall endeavour 



* Translated from Poggendorff's Annalen, June 1867- 

 t Phil. Mag. S. 4. vol. xxvi. p. 81. 



