318 Mr HARRIS'S Experimental Inquiries concerning 



ing regularly hardened and magnetized^ and the centre poles as- 

 certained as before ; it was 17 inches long, 1 inch wide, and 0.2 

 of an inch thick ; the constant distance a* at which the attrac- 

 tive force acted on the suspended cylinder #, was 0.2 of an inch, 

 and the distances are expressed in inches. 



TABLE XVII.* 



53. As all the known operations of nature are generally of the 

 most simple kind, it is not unreasonable to suppose, that where- 

 ever we find a compound law, that law may be resolved finally 

 into two or more elementary ones. Thus, we have found, that 

 the absolute force of attraction exerted between a magnet and a 

 mass of iron, or between one magnet and another, and which 

 has been found to increase in an inverse ratio of the square of 

 the distance, is resolvable into two simple elementary actions 

 (37, 38), one depending on the induced force in the iron, the 

 other on its distance from the magnet. We may, therefore, sup- 



* In a series of experiments of this description, where the forces are at first very 

 inconsiderable, but afterwards increase rapidly, it becomes necessary to vary the di- 

 mensions of the cylindrical counterpoise W, Fig. 1, by which means we are enabled 

 to examine the force in any point of the bar at a small distance ; whilst the degrees 

 being previously estimated in grains of absolute weight, the whole can be expressed 

 as if the same counterpoise had been employed throughout the experiment, as before 

 explained (47), a certain number of degrees with one counterpoise corresponding 

 to a given number with the other; 



