STUDIES ON MAGNETIC DISTRIBUTION 



119 



electromagnets than in permanent magnets. At first I thought it 

 might be due to the direct action of the helix, but on trial found that 

 the latter was almost inappreciable. I do not at present know the 

 explanation of it. 



As before mentioned, Coulomb has made many experiments on the 

 distribution of magnetism on permanent magnets; and so I shall only 

 consider this subject briefly. I have already given one or two results 

 in Table XII. 



654321 



FIG. 5. Results from electromagnets. 



A. Iron, from Table XI. 



B. Steel, from Table XII, magnetized same as originally. 



C. Steel, from Table XII, magnetized opposite to its original magnetism. 



6 S 4 3 2 1 O 



FIG. 6. Results from steel permanent magnets. 



D. Magnetized in its original direction, Table XII. 



E. Magnetized opposite to its original direction, Table XII. 

 Scale four times that of Fig. 5. 



The following Tables were taken from two exactly similar Stubs' 

 steel rods not hardened, one of which was subsequently used in the 

 experiments of Table XII. They were 12-8 inches long and -19 inch 

 in diameter. 



The coincidence of these observations with the formula is very re- 



