MANNl SOME STUDIES IN MAGNETISM 17 



The apparatus needed is inexpensive and most of it very easily 

 obtained. It includes a lodestone, bar magnet, compass, two 

 or three knitting needles, a half-dozen sewing needles, a few 

 tacks, pins and nails (wire and cut nails), a cork, a piece of 

 sewing silk, some sort of support from which to suspend 

 needles, a little cheese-cloth sack of iron filings and several 

 large sheets of paper for each group. Besides these, they have 

 used a wall map, a schoolroom globe and a couple of soft iron 

 rods a foot and a half long. The use of a laboratory is not neces- 

 sary, though convenient. When mapping fields of force with 

 iron filings, the sheets of paper were laid on the floor and the 

 children gathered around them. They have taken up the follow- 

 ing topics, all of which are treated in textbooks and accessible 

 to any teacher, even in a country school. The class has used no 

 text. 



I. Study of the lodestone. 

 Examination. 

 Experiments with tacks and discovery of poles as 



spots when attraction is strongest. 

 What lodestone is; where found. 

 Making magnets of needles by rubbing them with 



pole of lodestone. 

 Kind of magnet thus made, artificial. 

 11. Study of artificial magnets. 

 'Bar 

 Horseshoe. 

 Experiments with large number of different things 

 and classification into magnetic substances and 

 non-magnetic substances. 

 Best way to magnify a needle. 

 Poles of a magnet. 



Experiment with suspended magnetized knitting 

 needle and discovery of north-seeking and south- 

 seeking pole. 



III. The Compass. 



Its use; great value to sailors. 



IV. Law of magnets. 



Experiments with two magnetized needles floated on 

 cork and observation of behavior of poles toward 

 each other; bar magnet held near suspended needle, 

 etc. 



