HOW COULD AN EXPLORER FIND THE POLE 8 9 



HOW COULD AN EXPLORER FIND THE POLE? 



By Professor HARRY FIELDING RBID 



JOHNS HOPKINS UNIVERSITY 



THE claim to have reached the north pole, a point sought for sev- 

 eral hundred years by many intrepid explorers, must, of course, 

 be substantiated by adequate proof; and it may interest readers of this 

 magazine to know what kind of proof is possible and necessary, and 

 what observations the explorer must make to determine his geograph- 

 ical position when he is in the neighborhood of the pole. 



Let us say, in the first place, that neither photographs, which only 

 show the condition of the ice, but do not indicate whether they were 

 taken near the pole or several hundred miles from it, nor the testimony 

 of human beings, gives any evidence whatever that an explorer has 

 been to the pole. Persons who were not actually with the explorer can 

 only express their confidence in his good faith, in his knowledge of the 

 proper astronomical observations to be made, and in his ability to make 

 them with sufficient accuracy. Persons who accompanied him could 

 only vouch for the fact that he did not remain in camp at a comfortable 

 distance from the pole and manufacture observations, but that he actu- 

 ally traveled in the general direction of the pole, that on a certain date 

 he claimed he was there, and that he made frequent astronomical ob- 

 servations on the route. 



The only evidence which can at all satisfactorily show that an 

 explorer has been near the pole is that afforded by observations on the 

 sun or stars, capable of determining his successive positions at the 

 times they were taken. Other evidence might prove the negative; 

 such as inconsistencies in the narrative, inadequate time or insufficient 

 food for the distance traveled, the description of phenomena which 

 could not have been seen at the place where the explorer thought he 

 was; and so on. It is impossible to foresee the many discrepancies 

 which might show that an explorer has not been to the pole ; they will 

 not be considered here, as this article is not controversial, but merely 

 aims to set forth, as simply as possible, what kind of observations must 

 decide the claim of having reached the pole. 



Confining our attention for the moment to observations on the sun, 

 for the sake of simplicity of statement, we may say that the determina- 

 tion of one's position anywhere on the earth depends upon measuring 

 the altitude of the sun above the horizon at two times, the second 

 being, preferably, after the direction of the sun has changed by 90°. 

 This becomes clear if we consider Fig. 1. Let us suppose the sun is 



