192 PHENOMENA ACCOMPANYING PROPAGATION OF ELECTRICITY. 



the result of an optical illusion, due to a very rapid succession of jets emanating 

 from diireioiit points, and wliicli, in reality, are not simultaneous. This is a 

 point for examination. 



However this may be, it is evident that the study of the stratification of elec- 

 tric light, and of the action of the magnet on the discharges in different gaseous 

 mediums, discloses differences between those mediums which can only result 

 from their difference of molecular constitution. Density, in particular, would 

 appear to have a great influence on this order of phenomena, since we see hy- 

 drogen manifest them in so feeble a degree, while the vapors of Avater, and 

 especially of alcohol and ether, present them in so decided a manner. The 

 proper nature of elastic fluids, opposing more or less resistance to the transmis- 

 sion of electricity, must, doubtless, also play its part. It might not be impos- 

 sible then, that, in a more detailed and more exhaustive study of the phenomena 

 with which our attention has been occupied, and more particularly of those re- 

 lating to the action of the magnet on electric currents propagated in much rare- 

 fied elastic fluids, Ave may be able to find the means of acquiring some ncAV ideas 

 on the physical constitution of bodies, and on the manner in which the propa- 

 gation of electricity is therein efi'ected. 



