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VIII. On a Remarkable Case of Magnetic Intensity of a Chrono- 

 meter. By GEORGE HARVEY, Esq. M. G. S. M. A. S. &c. 



(Read November 17. 1823. ) 



A. BOX Chronometer having lately come into my possession, ex- 

 hibiting remarkable proofs of strong and active Magnetism, I 

 was induced to examine it particularly, and to ascertain the in- 

 tensities of its different parts, by means of an apparatus resem- 

 bling that employed by COULOMB, and which was capable, from 

 its very delicate construction, of indicating the existence of the 

 minutest traces of attraction. 



By denoting the power of the terrestrial magnetism by 100, 

 the intensity of the Chronometer, one inch above the centre of 

 its crystal, was only 90.79, when the hour of xn pointed to the 

 north ; but, on turning the time-keeper, so as to bring ix into 

 the same direction, the intensity was augmented to 102.29, the 

 position of the oscillating cylinder remaining unchanged ; and by 

 again turning it another quadrant, so as to bring vi to the north, 

 the intensity again declined to 90.69, corresponding very nearly 

 with the result determined in the first position ; and, lastly, when 

 in was brought into the same situation, the measure of the in- 

 tensity farther declined to 78.89 : So that the attraction was a 

 maximum when ix was directed to the north, and a minimum 

 when in was brought into the same situation ; and what is farther 

 remarkable, the nearly equal intensities corresponding to the 

 positions of xn and vi, approach very closely to a state of equa- 

 lity, with the mean of the maximum and minimum intensities. 



