464 Scientific Intelligence. [Juki: 



This question must be examined before we can pretend to enter 

 on any discussion of theories. And the present state of the inquiry 

 is precisely that in which the answer to this question forms the sole 

 important and legitimate object of attention. An attempt to answer 

 it, has formed the subject of the author's labours for some time past, 

 by a comparison grounded on a formula deduced from M. Cauchy's 

 researches ; which appears to give a very close accordance. The re- 

 sults will shortly be published. 



II. — Royal Institution. 



Comparison of the two theories of Electricitu. 3rd April, 

 Dr. Ritchie stated, that at present there are two theories which have 

 been proposed for the explanation of electrical phenomena. One 

 which is the simplest theory, supposes that they depend upon the 

 existence of a fluid universally diffused through matter and space, 

 the particles of which repel each other inversely as the square of the 

 distance. If we abstract a portion of this fluid from a body, the 

 latter becomes negatively electric : while if we add a portion, we 

 produce the phenomena exhibited by positive electricity. 



Another theory considers electricity to be a compound substance, 

 consisting of two elements, positive and negative electricity. None 

 of the phenomena are observed until this fluid is decomposed, and 

 then a portion of it goes to the attracted body. 



Upon this supposition we can best explain why divergence of the 

 gold leaves in an electrometer should take place in vacuo. Perhaps, 

 the fluid may be the ether, to which the phenomena of light seem 

 attributable. But unless it be a compound fluid, it is not possible to 

 explain the fact, that when a vessel, in which there is a small aper- 

 ture at the bottom is filled with water, when it is attached to either 

 conductor of the machine, there is formed a regular stream through 

 the aperture. 



Now, if there were two fluids the same appearances should not be 

 exhibited at both conductors. When a bit of wax is attached to 

 either conductor, heated, and then the machine set in motion, the 

 wax is thrown upon white paper held below it, in the form of a 

 beautiful thin film. It is difficult to explain the fact, that when we 

 place a card between two fine points, and discharge an electric jar 

 through them, the card will be pierced opposite to the negative point. 

 The reason perhaps is, that the paper is a better conductor of one of 

 the elements of the fluid than of the other. The card on each side 

 presents the same appearance, which leads to the conclusion, that a 

 fluid has passed through from both sides. 



According to the theory of Franklin, the actual particles of matter 

 repel each other, which is contrary to the law of gravitation. 



By considering electricity as a compound body we can explain also 

 the electrophorus. 



In order to confirm the idea of the existence of two elements, we 

 can by a beautiful experiment separate one element from the other. 



If we place two conductors united by their contact with fine points, 

 at a considerable distance from the conductor attached to the ma- 

 chine, charge the machine, and then suddenly remove one of the 

 separate conductors to the electrometer, we obtain a divergence in 



