MAGNETISM. 57 



unmagnetic state of the body, and the distance be- 

 tween them. 



Magnetic Action. 



The system of magnetic emanations, by which the 

 phenomena of the action of magnets at a distance 

 was formerly explained, has long been deservedly 

 exploded, and magnetic action has been resolved into 

 the more general and more simple fact of attraction 

 and repulsion, between the particles of all matter, 

 according to a certain function of their distance. 



The magnetic agencies are referrible to one of two 

 contrary polarities, the northern and the southern. 



Sir Isaac Newton's Magnet. 



The smallest natural magnets generally possess 

 the greatest proportion of attractive power. The 

 magnet worn by Sir Isaac Newtek, in his ring, 

 weighed only three grains, yet it was able to take 

 up 746 grains, or nearly 250 times its own weight ; 

 whereas magnets weighing above two pounds, seldom 

 lift more than five or six times their own weight. 



Iron. 



One magnet attracts another with less force than 

 it does a piece of iron; but the 'attraction begins at 

 a greater distance. The power of a magnet is weak- 

 ened by heat. 



Magnetic Attraction and Repulsion. 



Magnetic attraction only takes place betwixt the 

 opposite poles of two magnets. When either the 

 north or south poles of two magnets are placed near 

 each other, they repel ; but a north and south pole 

 attract each other. 



That magnetic attractions and repulsions follow 

 the law of the square of the distance has been regarded 



