38 



OUR OWN WORLD 



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 in- 

 different about the direction in which it points ? 



FIGURE 13. e discovery that a bar of loadstone 



or a magnetic needle, if floated or freely 

 suspended, will invariably assume a definite position was 

 made in the Far East at a very early date, but it was put 

 to no particular use in the sailing of ships until about the 

 middle of the thirteenth century. Since then it has 

 enabled sailors to go far out from the sight of land and 

 yet always to know the direction in which they are going. 

 It was supposed even up to the time of the first voyage of 

 Columbus that 

 the magnetic 

 needle always 

 pointed toward 

 the north star or 

 perhaps at some 

 place a little to 

 the east of it. 

 The sailors of 

 Columbus were 

 greatly alarmed 

 when they found 

 as they sailed 



REGION AROUND THE NORTH MAGNETIC POLE 

 The + marks the position of the pole. 



west that the needle swung off to the west of the true north. 

 This difference in the direction of the needle from a true 

 north and south line is called the declination. The west- 

 ward declination was one of the great discoveries of Colum- 



