OF ARTS AND SCIENCES. 



295 



b. The Armature, 



The last three vahies of the curve of magnet, under a should be 

 corrected so as to read, 



It is evident from this experiment, 1st, That the magnetism spreads 

 over the armature. 



2d, That the zero point is almost immovable. This was proved 

 repeatedly with various magnets and armatures ; and even the most 

 delicate test possible — that of testing the change of distribution at 

 the zero point, when the armature was suddenly removed, by tlie 

 current induced in a helix — even this failed to show more than the 

 very slightest change. 



3d, That the Mdiole farther end of the magnet is unaffected by the 

 armature. This was tested and proved in the same way. 



4th, That probably the permanent magnetism of the armature should 



