A LECTURE ON MAGNETISM. 361 



of your magnet successively up to either end of the needle. 

 Both the poles, you find, attract both ends of the needle. 

 Replace the needle by a bit of annealed iron wire, the same 

 effects ensue. Suspend successively little rods of lead, 

 copper, silver, or brass, of wood, glass, ivory, or whalebone ; 

 the magnet produces no sensible effect upon any of these 

 substances. You thence infer a special property in the 

 case of steel and iron. Multiply your experiments, how- 

 ever, and you will find that some other substances besides 

 iron are acted upon by your magnet. A rod of the metal 

 nickel, or of the metal cobalt, from which the blue color 

 used by painters is derived, exhibits powers similar to those 

 observed with the iron and steel. 



In studying the character of the force you may, how- 

 ever, confine yourself to iron and steel, which are always 

 at hand. Make your experiments with the darning-needle 

 over and over again ; operate on both ends of the needle ; 

 try both ends of the magnet. Do not think the work stu- 

 pid ; you are conversing with Nature, and must acquire a 

 certain grace and mastery over her language ; and these 

 practice can alone impart. Let every movement be made 

 with care, and avoid slovenliness from the outset. In every 

 one of your experiments endeavor to feel the responsibility 

 of a moral agent. Experiment, as I have said, is the lan- 

 guage by which we address Nature, and through which she 

 sends her replies ; in the use of this language a lack of 

 straightforwardness is as possible and as prejudicial as in 

 the spoken language of the tongue. If you wish to become 

 acquainted with the truth of Nature, you must from the first 

 resolve to deal with her sincerely. 



Now remove your needle from its loop, and draw it from 

 end to end along one of the ends of the magnet ; resuspend 

 it, and repeat your former experiment. You find the result 

 different. You now find that each extremity of the magnet 

 attracts one end of the needle and repels the other. The 

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