54 Thoughts on Magndifm. 



magnetsj when at liberty to move with a certain degree of freedom, and iron, when a fuf- 

 ficient number of its particles are arranged in that direction, and has fufficient liberty to 

 conform to it, points to thofe poles. Hence this property is called Polarity. 



The magnetic power is greater or lefler according to the number and homogenity of the 

 particlesy/«//ar/y and magnetically arranged. . Hence fm:".l magnets may be more powerful 

 than a larger, and hence a magnet will attradl a magnetized needle at a greater diftance than 

 one not magnetized. 



The magnetic power decreafes in a certain ratio of the diftance of the particles that exer- 

 cife it. Hence it is ftrongeft in the point of contaft, and at the poles, as it is there moft 

 utifaturated, and weakeft in the central part, which feparates the two oppofite poles. 



When a magnet is broken into fmall pieces its power is nearly dcftroyed, becaufe though 

 the poles fliould be all of the fame kind, yet the diftance of each from the oppofite pole is 

 fo fmall that their powers counteraft, and confequently deftroy each other. 



If when a needle is attradled by the fouth pole of a magnet a bar of iron be placed on the 

 north pole, the needle is ftill more ftrongly attracted, becaufe the iron acquires alfo a fouth 

 pole, whofe force is joined to that of the magnet. 



If two needles be fufpended from any given pole of a magnet they will diverge, becaufe they 

 both acquire the fame polar arrangement. If a bar of Iron be laid on that pole of the magnet, 

 the divergence will diminifh, becaufe the next end of the iron will acquire the difpofition of 

 the oppofite pole, and confequently counteradl the repulGve power of the magnet. 



A magnet will not tranfmit its power through a bar of iron if this be too long. 

 Mufchenbrouck limits their length to fix feet, but this depends on the ftrength of the 

 magnet. 



The power of a magnet (every thing elfe being equal) depends on the number of its furfaces 

 magnetically arranged, and the accuracy of that arrangement. 



The arrangement is accurate when the fynonimous furfaces are exactly parallel to each 

 other, and originally conformed to and parallel with thofe of. the great general magnet. 



The magnetic attradtion is ftrongeft in the diredlion perpendicular to the magnetic 

 furfaces, and weakens in proportion to the magnitude of the angle of direction with the 

 perpendicular, and confequently is null when at a right angle with it. Hence the mag- 

 netic power feems concentrated at the poles^ and the lateral powers are the weakeft, as 

 they originate only in the oblique diredion of furfaces, or from furfaces inaccurately 

 arranged. 



(To ie continued. J 



Deferlption 



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