152 CORRELATION OF THE PHYSICAL FORCES. 



Here again is a fine illustration of this strong 

 power of magnetism. It is a magnet of the 



Fig. 53. 



same sort as the one you have just seen. I am 

 about to make the current of electricity pass 

 through the wires which are round this iron for 

 the purpose of showing you what powerful 

 effects we get. Here are the poles of the mag- 

 net ; and let us place on one of them this long 

 bar of iron. You see as soon as contact is made 

 how it rises in position (fig. 54) ; and if I take 

 such a piece as this cylinder, and place it on, 

 woe be to me if I get my finger between ; I can 

 roll it over, but if I try to pull it off, I might 



