AMERICAN 
JOURNAL OF SCIENCE AND ARTS. 
(SECOND SERIES.] 
Arr. XVI.—On Terrestrial Magnetism, as a mode of Motion; by 
Puiny Earve Cuasz, M.A., 8.P.A.S. 
' 
action of the sun’s rays, the precise “ occasional currents” for 
which he was seeking, as the probable cause of magnetic storms, 
Mr, Airy has recently sent me acopy of his very interesting 
Paper (Zrans. Roy. Soc., 1863, Art. XXIX), and its perusal has 
ey strengthened this belief. 
why 
the atmospheric changes, whether of humidity, es 
i : 
all-pervading ether may be both the source and the receptacle 
of all the various forms of force. In its principal features, this 
theory harmonizes with the now generally accepted belief in the 
Mechanical origin of light and heat, but in its details it involves 
some new and interesting special applications, which I have en- 
deavored partially to develop. . 
It will be readily seen, by a reference to my communication 
of April 15 (Proc. A. P. A ie ix, 367, et seq.), that the mechan- 
wat action of the currents to whose electric action mpére 
Scr} d the origin of terrestrial magnetism, produces two oppo- 
Site spirals in the air and zther,—the lower moving from the 
* From the Proceedings of the American Philosophical Society, Oct. 21, 1864, 
Ax Jour. Sc1.—Szcoxp Series, Vou. XXXIX, No. 116—Mancu, 1865. 
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