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LXIII. Electromagnets. — VI. The Tension of Lines of Force, 

 By R. H. M. Bosanquet. 



To the Editors of the Philosophical Magazine and Journal. 



Gentlemen, 



THE experimental determination of the magnetic attrac- 

 tion corresponding to measured values of magnetic 

 induction has long been in my mind. It has some bearing 

 on my theory of permeability (see Phil. Mag. ser. 5, xix. 

 1885, p. 87 (note) and p. 94, in both of which places i$ 2 is 

 inadvertently printed for 2S 2 ) ; but its independent interest is 

 considerable. 



After the following experiments were arranged, a paper on 

 a somewhat similar subject was read to the Royal Society by 

 Mr. Shelford Bidwell. From the accounts which have been 

 so far published, the method of this paper appears to be entirely 



FIXED ELECTRO-MAGNET = = = 



SMALL COIL FOR MEASURING 



INDUCTIONS 



MOVEABLE ELECT RO-MACNET = = = 



£> 



COUNTERPOISE 



SCALE PAN 



different from mine, as the magnetizing force and the weight 

 were alone directly measured : and in other respects the 

 method differs essentially from that which I have adopted. 



