Ejfecl of Magnetlfm on Time-pieces. ity 



Having pretty well fatisfied myfelf as to the caufe, I now 

 proceeded to determine the poles of the balance. With that 

 view I placed its axis in a vertical fituation, and of courfe its 

 plane was horizontal; and I was much furprifed to find that, 

 in that pofition, it pofTefled fufficient polarity to overcome 

 the friftion upon its pivot ; for it readily turned on its axis 

 to place its north pole towards the north. Making a mark 

 on that fide that I might know its north pole, I then re- 

 peatedly turned that point towards the fouth; and, when left 

 ftt liberty, it as often renamed its former pofition, performing 

 a few vibrations before it quite fettled itfelf in its fituation 

 and came to reft — exactly as a heedle would do if fufpended 

 in the fame manner. 



I was extremely happy that I had obferved thefe effecls 

 before I brought a magnet to make the experiment I firft in*- 

 tended, as I might, and as others alfo might have concluded, 

 that the polarity had been produced by the approach of the 

 magnet. I now, however, brought a magnet into the fhop, 

 and, prefenting its fouth pole to the marked fide, that is, to 

 the north pole of the balance, the balance continued at reft ; 

 but upon prefenting the north pole to the marked place, it 

 immediately receded from the magnet, and renamed its for- 

 mer pofition whenever the magnet was withdrawn. 



No doubt now remaining: as to the fafts, and beino- in 

 pofleffion of the pofition of its poles, I proceeded to examine 

 the effects produced by this caufe upon the watch's rate of 

 going. Having put on the pendulum fpring, and replaced 

 the balance in the watch, I laid the watch with the dial 

 upwards, that is, with the plane of the balance horizontally, 

 and in fuch a pofition that the balance when at its place of reft 

 fhould have its marked fide toward the north: — in this fitua- 

 tion it gained 5' 35'' in twenty-four hours. I then changed 

 its pofition fo that the marked fide of the balance when at reft 

 fhould be towards the fouth, and, obfcrving its rate of going 

 for the next twenty-four hours, found it had loft 6' 48 1 '—- 

 producing, by its change of pofition only, a difference of 



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