11 



STUDIES ON MAGNETIC DISTK1BUTION 



[Philosophical Magazine [4], L, 257-277, 348-367, 1875] 

 [American Journal of Science [3], X, 325-335, 451-459, 1875; XI, 17-29, 103-108, 1876] 



PART I. LINEAR DISTRIBUTION 



CONTENTS 



I. Preliminary remarks. 

 II. Mathematical theory. 



III. Experimental methods for measuring linear distribution. 



IV. Iron rods magnetized by induction. 



V. Straight electro-magnets and permanent steel magnets. 

 VI. Miscellaneous applications. 



I. 



In a paper of mine published about two years ago, I alluded to some 

 investigations which I had made in 1870 and 1871 on the distribution 

 of magnetism. It is with diffidence that I approach this subject, being 

 aware of the great mathematical difficulties with which it is surrounded. 

 But as the facts are still in advance of what is known on the subject, 

 and as I see that other investigators * are following hard upon my foot- 

 steps, I thought it would be well to publish them, particularly as it is 

 no fault of mine that they did not appear some years ago. 2 The mathe- 

 matical theory which I give, although not particularly elegant, will at 

 least be found to present the matter in a new and more simple light, 

 and may be considered simply as a development of Faraday's idea of 

 the analogy between a magnet and a voltaic battery immersed in water. 

 I shall throughout speak of the conduction of, and resistance to, lines 

 of magnetic force, and shall otherwise treat them as similar to lines of 

 conducted electricity or heat, it now being well established from the 

 researches of Professor Maxwell and others that this method gives 

 exactly the same results as the other method of considering the action 

 to take place at a distance. 



In arranging this paper I have thought best to give the theory of 



1 Particularly M. Jamin. 



2 All the experiments referred to in this paper were made in the winter of 1870-71. 



