286 Researches in the Theory and Calculus of Operations. 



all kinds of vegetable and animal growth, and constitutes 

 a large portion of the substance of fallen meteorites. In a 

 series of the elements arranged with respect to magnetic 

 capacity, iron stands as the paramagnetic head of the de- 

 scending scale which passes through zero, and finally ter- 

 minates in the element bismuth as its diamagnetic antipode. 

 "When pure and in the state termed soft iron, it is not mag- 

 netic, but may be temporarily rendered so by induction or 

 influence, in a manner similar to the production of electri- 

 city by influence in an electric conductor. But when har- 

 dened by hammering or compression, or when converted 

 into steel (carburet of iron), it can be rendered permanently 

 magnetic by several different processes elsewhere described. 



24. The Earth is a magnet. 1° It is assumed that the 

 central portion of the earth contains the force of a core of 

 soft iron. The chemical action, initiated and sustained by 

 the Sun's influence, between the heterogoneous elements 

 of the fluid portions of the surface and the contiguous solid 

 portions of the earth's crust, acts inductively through the 

 drier and harder portions of the shell, upon the axial iron 

 core, similarly as the waters of the ocean act inductively 

 through the guttapercha covering of the submarine tele- 

 graph wire : the iron core, coincident with the earth's axis 

 of rotation, is continuously charged with electric force. 

 2° Experiment has sufficiently shown that when a portion 

 of a metallic ring is heated, an electric current is started in 

 it. Now the terrestrial meridians may be regarded as com- 

 prising so many contiguous atmospheric rings which are 

 daily successively heated by the Sun's rays, each meridian 

 unequally from the poles to the equator. An electric current 

 is thus generated, which draws upon the central electrified 

 core through the poles, calling forth two opposmg currents, 

 a northern or negative and a southern or positive, which 

 meet and pass each other at the magnetic equator, and give 

 direction to the magnetic needle. The successive and alter- 



