312 INTERESTING SCIENTIFIC WORK IN THE ARCTIC 



crosses the celestial Equator coming north and going south. 

 Supposing Dr. Cook had reached the North Pole on March 21, 

 he would see the sun gradually rise in the south and move right 

 round his horizon, in sight the whole time, and return again to 

 the south point. It would not rise or fall with regard to the 

 meridian, as the sun does in these latitudes, but would very 

 gradually rise along its whole course in the form of a spiral, and 

 this change in altitude would be equal to the change in the dec- 

 lination of the sun. 



"This gradual change in altitude goes on in the same spiral 

 manner until June 21, the date of the summer solstice, when the 

 sun has reached its farthest point north, and its maximum alti- 

 tude is about 23 % degrees. It then gradually falls in the same 

 manner toward the horizon, disappearing on September 22 and 

 remaining out of sight until the following March. The stars 

 would then be visible that is, all the stars between the Pole and 

 the Equator, and these stars would neither rise nor set, but 

 would describe great circles around the observer, remaining prac- 

 tically at the same altitude. 



"The stars, indeed, would be the most satisfactory and accu- 

 rate guides in determining the latitude when the Pole had been 

 reached, more especially the Pole-star itself, which would be in 

 the zenith and free from the uncertainties due to refraction, etc. 

 Unfortunately, only the sun is available in the summer, and 

 unless the explorer reaches the Pole near midsummer, when its 

 altitude is well above the horizon, at other times it is distorted 

 and affected by refraction, and errors of observation are un- 

 avoidable. The compass, of course, is still of use, but the north- 

 seeking end, instead of pointing north, would point south in 

 the direction of the North Magnetic Pole, which is situated in 

 North America, and some degrees to the south of the North Pole. 



"Traveling toward the North Pole, and when within reach of 

 his goal, an explorer should exercise the minutest care in his 



