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XLII. On Molecular Physics. By Prof. W. A. Norton*. 



[Continued from vol. xxx. p. 289.] 



rjiERRESTRIAL MAGNETISM.— In accordance with the 

 ideas already advanced as to the essential nature of electri- 

 cal excitation (vol. xxx. p. 107), we may conceive that the earth may 

 derive its magnetic condition from currents developed in its crust 

 by the impulsive action of the aether of space upon the molecular 

 atmospheres f. Both the rotatory and orbital motions of the 

 earth may be concerned in the production of such currents. 

 The rotation of the earth should develope currents at each point 

 of its surface, starting in a direction parallel to the equator, and 

 flowing from east to west. Also, if we consider the points of 

 the earth lying on or near the meridian whose plane passes 

 through the sun, and designate the velocity of the earth in its 

 orbit by V, and that of rotation by v, the absolute velocity of 

 the points in question will be Y+v on the side opposite to the 

 sun, and V— v on the side toward the sun. The current in the 

 former case, due to the velocity Y + v, will run from east to 

 west; and that in the latter case, due to the velocity V— v, will 

 run from west to east. The intensity of the former may be re- 

 presented by m(V + v) 2 , and of the latter by m(V — v)*. Taking 

 the difference between these two expressions, we obtain as the 

 excess of the intensity of the east and west current over the 

 other, 4m Yv. Such, then, would be the intensity of the effec- 

 tive current at any point, due to the combination of the velo- 

 city of rotation and the velocity in the orbit. At points of the 

 earth's surface at any moment in the vicinity of the meridian 

 at right angles to that just considered, the currents developed, 

 so far as they originate in the tangential action of the aether, 

 will be wholly due to the earth's rotation. At certain distances 

 from this meridian, the component of the orbital velocity, in a 

 direction parallel to the surface, will exceed the velocity of 



* From Silliman's Journal for January 1866. 



t As intimated in a former part of this memoir, the priority in the pub- 

 lication of the general theory that the earth derives its magnetic condition 

 from its collision with the aether of space is conceded to Professor Hinrichs, 

 of the Iowa State University, and formerly of Copenhagen. But the idea 

 was no less an original one with the author ; and his conception of the 

 essential nature of dynamic electricity, and the magnetic condition of the 

 earth, and his physical theory of terrestrial magnetic phenomena as result- 

 ing from the same supposed original cause, are materially different from 

 the views advanced by Professor Hinrichs. It will be seen also that the 

 theory now presented is but the complement to a previous series of re- 

 searches upon terrestrial magnetism, prosecuted at intervals through a 

 period of about twenty years, and a natural offshoot from the theory of mo- 

 lecular physics propounded in this paper. 



