14 LIGHT SCIENCE FOR LEISURE HOURS. 



THE EARTH A MAGNET. 



THERE is a very prevalent but erroneous opinion that 

 the magnetic needle points to the north. I remember 

 well how I discovered in my boyhood that the needle 

 does not point to the north, for the discovery was im- 

 pressed upon me in a very unpleasant manner. I 

 had purchased a pocket-compass, and was very anxious 

 not, indeed, to test the instrument, since I placed 

 implicit reliance upon its indications but to make use 

 of it as a guide across unknown regions. Not many 

 miles from where I lived lay Cobham Wood, no very 

 extensive forest certainly, but large enough to lose 

 oneself in. Thither, accordingly, I proceeded with 

 three schoolfellows. When we had lost ourselves, we 

 gleefully called the compass into action, and made from 

 the wood in a direction which we supposed would lead 

 us home. We travelled on with full confidence in our 

 pocket guide ; at each turning we consulted it in an 

 artistic manner, carefully poising it and waiting till its 

 vibrations ceased. But when we had travelled some 

 two or three miles without seeing any house or road 

 that we recognised, matters assumed a less cheerful 

 aspect. We were unwilling to compromise our dignity 

 as ' explorers ' by asking the way a proceeding which 

 no precedent in the history of our favourite travellers 

 allowed us to think of. But evening came on, and with 



