36 



FIRST TEAR SCIENCE 



lines upon them connecting places of equal declination. 

 These lines are called isogonic lines. 



18, Magnetism. Experiment 11. Having pushed a long cam- 

 bric needle through a small disk of cork so that it will float horizon- 

 tally, carefully place the disk and needle upon the quiet surface of a 



105 95 



REGION AROUND THE MAGNETIC POLE. 



large dish of water. Does the needle assume any definite direction? 

 Taking the needle from the water stroke one end of the needle from 

 the cork out with the north end of a magnet and the opposite end 

 with the south end of a magnet. When the needle is again floated 

 on the water is it indifferent about the direction in which it points? 

 What has caused the change, if there is any ? 



Experiment 12. Suspend by a string a short bar magnet in a 

 sling made from a bent piece of wire. Turn it around in several 

 different directions. After each change allow it to come to rest in 



