.'300 Mr HARRIS'S Experimental Inquiries concerning 



vary the magnetic developement in da (19), whilst its distance 

 from the opposed iron n c is constant. 



The actual results are given in Tables VIII. and IX., the 

 distance of x being made constantly equal to three-tenths of an 

 inch. In Table VIII., D signifies the variable distance cd, and 

 / the corresponding force, as expressed by the number of de- 

 grees which the index declined, the constant distance a b be- 

 ing two-tenths of an inch. In Table IX., F signifies the va- 

 riable magnetic intensities produced by approximating the mag- 

 netic bar bm, through the respective distances 0.6, 0.3, 0.2, 0.15 

 of an inch, in order to obtain the relative forces 1, 2, 3, 4, (9) ; 

 /'is the force of induction as before ; the constant distance cd 



being in this case also two-tenths of an inch. 



TABLE VIII. 



TABLE IX. 



37. Having considered some of the principal phenomena of 

 induced magnetism, we may now investigate more particularly 

 the force made up of the reciprocal attraction between a magnet 

 and a mass of iron, when placed at different distances from each 

 other. It maybe observed (19), that this combined force exert- 

 ed between a mass of iron be, Fig. 5, in a temporary magnetic 

 state, and the suspended body x, which must be considered also 

 in a temporary magnetic state, is, at a given distance, directly 

 proportional to the intensity of the inductive magnet m, and in 

 an inverse proportion to the distance cd, the magnet m remain- 

 ing unchanged. From which we may conclude, considering 



