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tions, I have doubted whether in any case an electric 
current directly induces a current in a parallel conductor, 
and formed an hypothesis, by which I conceive many of 
the phenomena, otherwise discordant, may be accounted for. 
The full development of my hypothesis might lead to the 
introduction of some ideas, in relation to the constitution 
of matter, foreign to the subject of this communication : I 
must, therefore, assume certain positions which admit of 
considerable doubt. 
I will assume that matter is composed of ponderable 
atoms not in absolute contact, but separated by intervening 
space, or by imponderable matter; and I consider it un- 
necessary at present to determine, or even to consider, 
whether the space intervening between the ponderable par- 
ticles be occupied by an imponderable element, as caloric, 
by an ether, as assumed in some of the theories of light, by 
vibration, as assumed in other theories, or by any other 
manner or form of mere force. Such compound consti- 
tution of matter is necessary, in order to admit of any 
explanation in what manner matter may become affected by 
any kind of polarity. 
I will also assume that when matter becomes polar its 
molecular condition is disturbed; that when the molecular 
constitution of a body is disturbed electricity is developed, 
though the exhibition of any electrical phenomena will 
depend on the circumstances permitting the establishment 
of an electric circuit, as certain conditions of matter will, 
in many cases, so permit the return of the electricity 
through a short circuit within the matter in which it is 
developed, that no external effects can be observed. 
I also assume, as a correlative circumstance, that an 
electric current produces molecular disturbances, not only 
in the matter conducting the current, but also in the con- 
tiguous matter, whether conductor or non-conductor; that 
