SOME STUDIES IX AL 1 GNETISM 19 



out from north-seeking pole to south-seeking ])ole 

 in numberless planes until they form an invisible 

 sphere of influence about the magnet. 



Place two magnets with like poles near tog-ether and 

 demonstrate the direction of the lines of force by 

 means of filings. Place two magmets with unlike 

 poles near one another. Try placing two magnets 

 side by side with like poles together; with unlike 

 poles together. 



(Gilley is good for suggestions.) 



Develop a definition of magnetic field and lines of 

 force. 

 IX. Making magnets by simply (i) putting a piece of iron or 

 steel in contact with a magnet. 



(2) By merely bringing it within the field of force of a 

 strong magnet. 

 X. The earth as a magnet. 



Illustrate by putting a magnet within a globe, or build 

 a sphere around a magnet (as suggested by Gilley), 

 and experiment by placing the compass in different 

 positions upon the globe. How does it point? Lo- 

 cate on map and on globe, the north and south 

 magnetic poles. Care must be taken here or con- 

 fusion will arise between the magnetic and the geo- 

 graphical poles. Use the suspended needle and with 

 it held near the globe containing the magnet, let it 

 trace lines of force about the globe. Sketch on the 

 board. 

 XI. Dipping needle. 



If we should take a magnetized knitting needle sus- 

 pended from a string to the north magnetic pole of 

 the earth, what position would it take? At the 

 south magnetic pole? Half-way between them? 

 How would it stand here? (Slanting.) Can we 

 find out how much it would slant? (Class suggest.) 

 (Millikan and Gale give excellent directions for 

 making a dipping needle. Everything depends up- 

 on the care with which the needle is balanced and 

 upon not destroying the equilibrium while magnetiz- 

 ing it.) 



]^Ieasure the slant or inclination in degrees by using 



