88 : The Atlantic 



of our balance against the force of gravity. In any event, it is possible 

 for most people to tell w^hich star, if any, is immediately overhead. In 

 case of doubt, the accuracy of observation may be increased by look- 

 ing upward and walking around in a circle if on land, or rowing 

 about in a circle if afloat. 



A knowledge of the patterns of the stars together with a recogni- 

 tion of which star is overhead, permits the observer to ascertain his 

 own location on the earth. Gatty points out that if then the observer 

 knows that some other star is immediately over some island or point 

 of land he will, by directing his course toward that star, also be di- 

 recting his course toward the desired point of land. The navigators 

 among the Polynesian people are said to have studied the stars in 

 their relationship to various islands so that they had a precise knowl- 

 edge and tradition which enabled them to know which stars habitu- 

 ally passed over which islands. 



There is a curious corollary to this method of navigation, namely 

 that the navigator who pursues it and who sets his course by a star 

 automatically follows a great circle course. When European navigators 

 began to travel across the Pacific they would occasionally observe 

 and refer to the fact that Polynesian canoes apparently had taken 

 great circle courses. How this could have been done was a great mys- 

 tery to these European navigators who had always depended on opti- 

 cal instruments, chronometers and compasses in setting their courses 

 at sea. 



The fact that the Polynesians used the principle of the zenith star 

 as a method of navigation suggests the possibility that other pre- 

 scientific people who are known to have made extensive voyages on 

 the seas, out of sight of land, employed the same method. 



Western sailors of today steering a ship at night usually guide 

 themselves by a star. This has nothing to do with the zenith star 

 method of navigation. This modern usage sets the course and gives 

 direction to the steersman by our conventional methods of navigation. 

 When the steersman is on his compass course he observes a star just 

 in line with his masts or the stem of the vessel. He steers by that for 

 a while and this relieves him of the strain of continually following a 

 compass. This is what Masefield referred to when he said: 



"All I want is a tall ship 

 And a star to steer her by." 



This is beautiful but it is not zenith star navigation. Still, so many 



