THE 



LONDON and EDINBURGH 



PHILOSOPHICAL MAGAZINE 



AND 



JOURNAL OF SCIENCE, 



[THIRD SERIES.] 



JULY 1834.. 



I. On Magnetic Attraction and Repulsion and on Electrical 

 Action. By Robert Were Fox*. 



HAVING observed, whilst I was using my dipping-needle 

 with its magnetic deflector (noticed in No. 20, Third 

 Series of the London and Edinburgh Philosophical Magazine : 

 vol. iv. p. 81), that the ratio of the magnetic forces was not 

 uniform, I was induced to enter upon a series of experiments 

 for the purpose of investigating these forces. 



Of the various methods I adopted, I think it may be suffi- 

 cient for me to describe that only which seemed on the whole 

 to be most satisfactory and decisive. 



To the extremity of a horizontal beam, delicately balanced 

 on knife-edges, a magnetic bar was attached, with its axis in a 

 vertical direction, and a counterpoise was suspended from the 

 other end of the beam. Immediately under the attached or 

 suspended magnet, and in the same vertical line, another si- 

 milar magnet was placed, in a glass tube, in which it could be 

 moved freely up or down, a graduated scale having been 

 fixed to the tube to mark the exact distance between the con- 

 tiguous poles of the two magnets ; and when the poles were 

 brought very near each other, mica, paper, card-board, &c, 

 were placed between them, 2, 4, or 8 pieces being pasted to- 

 gether to obtain the duplicate ratios of the distances. Minute 

 weights were suspended to ascertain the force of attraction or 



* Communicated by the Author, on the 9th of April last. 

 Third Series. Vol. 5. No. 25. July 1834. B 



