MAGNETISM 37 



whatever position it will Does it prefer any one position to all 

 others? 



Experiment 13. Suspend a bar magnet horizontally in a sling 

 and bring one of the ends of another bar magnet toward it. What is 



the effect? Reverse the ends of the magnet; is there 



any change in the position of the suspended magnet ? 

 Bring a large soft iron nail toward either end of 

 the suspended magnet. What is the effect? Re- 

 verse the ends of the nail. (Be careful that the nail 

 has not become permanently affected by the magnet.) 

 Is the effect the same as when the ends of the magnet 

 were reversed ? 



Bring pieces of copper, zinc, and other substances 

 toward the magnet. Do these affect it ? Notice that 

 the ends of the bar magnet are marked. What can 

 you state about the attraction or repulsion of similar ends of mag- 

 nets? Of opposite ends? Does it make any difference in its effect 

 on the suspended magnet toward which end the nail is brought? 

 What substances do you find attracted by the magnet? 



To the end of a small nail hanging by attraction to a magnet bring 

 another nail. How does the first nail act in respect to the second ? 



So much were some of the ancients impressed with the 

 property of loadstones for attracting iron that one of them 

 suggested building a great arch of this material in a temple 

 so that the iron statue of the goddess would remain sus- 

 pended in the air without resting upon any support. 

 There is an old legend that the iron coffin of Mohamet 

 rose and remained near the ceiling of the mosque in which 

 it was buried. 



It was early discovered that when pieces of steel were 

 rubbed on a loadstone they took on the properties of the 

 loadstone and become magnets. In the experiments with 

 magnets, it was found that like poles repelled and unlike 

 poles attracted, and that iron or steel in contact with a 

 magnet becomes magnetized. Iron and steel are practi- 

 cally the only' substances attracted by a magnet, although 



