244 Intelligence and Miscellaneous Articles. 



between the two poles of the electromagnets in order to study only 

 their isolated action, we shall quickly verify : — 



(1) That the phenomenon announced by De la Bive is equally 

 produced within the sphere of attraction of either of those poles ; 

 , (2) That the phenomenon is not inherent in the inducing current 

 alone, but that the current from any independent pile, interrupted 

 within that sphere of attraction, gives rise to the same effects. 



(3) That the extra current receives a very real and considerable 

 augmentation of tension. 



Oxygen being magnetic (as M. Edm. Becquerel has proved), 

 there was room to ask if some action of condensation or separation 

 of the constituent elements of air did not take place in the mag- 

 netic field of the pole. I therefore collected, by means of ordinary 

 aspirators, air from several points in that field ; and analysis of it 

 revealed none of these peculiar actions. 



. To give still more precision to this research, M. Duboscq and 

 I investigated the interference-phenomena, by submitting one of 

 the two luminous rays, or both at once, to the action of a powerful 

 electromagnet. The apparatus employed was the interferential re- 

 flector of M. Jamin. We caused the two rays, or one of them, to 

 pass successively into air, oxygen, nitrogen, hydrogen, carbonic 

 acid ; and in each of these different cases we could never observe 

 the slightest displacement of the fringes. 



The hypothesis of an atmosphere of vibrating wther around the 

 poles of magnets (a conclusion to which I have thought I could 

 come) would perhaps permit us to understand a little better than 

 it has yet been comprehended the phenomenon of induction by 

 magnets, discovered by Faraday. 



I seize this opportunity to say that I have repeated the experi- 

 ment of induction in vacuo, and at all pressures, without ascertain- 

 ing the least alteration, either to more or less, in the intensity of 

 the current produced. 



To this communication the author adds a Note relative to "the 

 magnetic atmosphere of magnets." Erom some experiments, 

 w 7 hich are to be realized with greater precision by means of appa- 

 ratus which is now being constructed, he believes he can infer the 

 mode of action of an electromagnet upon a cylinder of soft iron 

 placed along its axis. — Comptes Menclus de TAcad. des Sciences, vol. 

 lxxx. pp. 310-311. 



ON A NEW ELECTROMAGNET, FORMED OF CONCENTRIC TUBES OF 

 IRON SEPARATED BY LAYERS OF CONDUCTING WIRE. BY J. 

 CAMACHO. 



The new electromagnet, of which I have the honour to forward 

 a sketch to the Academy, was constructed for the purpose of 

 obtaining very considerable dynamic effects with relatively feeble 

 currents. 



Each of the cores consists of a series of concentric tubes, the 

 intervals between them being nearly equal to their thickness ; on 



