IN INCREASING THE INTENSITY OF ELECTRICITY. 547 



the first polarity; several alternations of this kind being observed*. 

 Now this is precisely what would take place if we suppose that the 

 principal current induces a secondary one in an opposite direction in 

 the air surrounding the conductor, and this again another in an oppo- 

 site direction at a great distance, and so on. The needles at different 

 distances would be acted on by the different currents, and thus the 

 phaenomena described be produced. 



The action of the spiral is also probably connected with the fact in 

 common electricity called the lateral discharge : and likewise with an 

 appearance discovered some j^ears since by Nobili, of a vivid light, pro- 

 duced when a Leyden jar is discharged through a flat spiral. 



The foregoing views are not presumed to be given as exhibiting the 

 actual operation of nature in producing the phaenomena described, but 

 rather as the hypotheses which have served as the basis of my investi- 

 gations, and which may further serve as formulae from which to deduce 

 new consequences to be established or disproved by experiment. 



Many points of this subject are involved in an obscurity which requires 

 more precise and extended investigation ; we may, however, confidently 

 anticipate much additional light from the promised publication of Mr. 

 Faraday's late researches in this branch o science. 



• Gumming 's Demonferrande, p. 247 ; also E-iinburgh Joiu-nal, October 

 1826. 



NOTE. 



[For an account of some recent investigations relative to the subject of the 

 preceding Articles, the reader is referred to " An Inquiry into the Possibility and 

 Advantage of the Application of Magnetism as a Moving Power : By the Rev. 

 James William M'Gauley, in the Report of the Dublin Meeting of the British 

 Association, 183.5." See Phil. Mag. and Annals, vol. vii. p. 306. A further 

 communication was made by the same gentleman at the Bristol Meeting, 1836. 

 — Edit.] 



Vol. I.— Part IV. 2 P 



