M. DE LA RIVE’S RESEARCHES ON THE VOLTAIC ARC. 
43 
The first principle is, that the passage of the electric current modifies, even in solid 
bodies, the arrangement of the particles ; a principle which I have already deduced 
from the experiments contained in my preceding memoir on this subject. The 
second principle is, that the action of magnetism, under whatever form it may be 
exerted, modifies alike the molecular constitution of all bodies, and that this modifi- 
cation lasts as long as the cause producing it endures, and only ceases with it. What 
is the nature of these two modifications? This is what we must endeavour to inves- 
tigate and to ascertain. I purpose to engage in this inquiry, and indeed I have 
already made some attempts of which it would, however, be premature to give any 
account. I shall confine myself at present to a single remark, which does not appear 
to me to be devoid of interest : it is, that the influence of magnetism on all conduct- 
ing bodies seems to impress on them, as long as it lasts, a molecular constitution 
similar to that which iron, and generally all bodies susceptible of magnetism possess 
naturally ; for it developes in them the property of producing, when traversed by 
interrupted currents, sounds identical with those emitted also by iron and other 
magnetic bodies when transmitting these currents, but produced in these last without 
requiring the action of a magnet. 
