82 THE WANDERINGS OF THE NORTH POLE. 



lutely exactly the same'? Would there be a difference, not indeed of 

 miles but of yards or of feet between the precise position of the pole on 

 the earth determined at successive intervals of time i? Would it be the 

 same if we carried out our comparisons, not merely between one year 

 and another, but day after day, week after week, month after month'? 

 No doubt the more obvious phenomena proclaim in the most unmistak- 

 able manner that the position of the pole is substantially invariable. 

 If therefore there be any fluctuations in its position, those could only 

 be disclosed by careful scrutiny of minute phenomena which were too 

 delicate to be detected in the coarser methods of observation. There 

 is indeed a certain presumption in favor of the . notion that absolute 

 constancy in the position of the pole need not be expected. Almost 

 every statement of astronomical doctrine requires its qualification, and 

 it would seem indeed unlikely that when sufiflcient refinement was intro- 

 duced into the measurements the position of the pole in the earth should 

 appear to be absolutely unalterable. Until a very recent period the 

 evidence on the subject was almost altogether negative; it was no 

 doubt recognized that there might be some fluctuations in the position 

 of the pole, but it was known that they would only be extremely small, 

 and it was believed that in all probability those fluctuations must be 

 comj)rised within those slender limits which are too much affected 

 by inevitable errors of observation to afford any reliable result. Per- 

 severance in this interesting inquiry has been at last rewarded; and 

 as in so many similar cases we are indebted to the labors of many inde- 

 pendent workers for the recent extension of our knowledge. We are, 

 however, at present most interested by the labors of Mr. Chandler, a 

 distinguished American astronomer, who has made an exhaustive exam- 

 ination into the subject. The result has been to afford a conclusive 

 proof that the terrestrial pole does undergo movement. Mr. Chandler 

 has been so successful as to have determined the law of those polar 

 movements, and he has found that when they are taken into consider- 

 ation, an important improvement in certain delicate astronomical inquir- 

 ies is the result. These valuable investigations merit, in the highest 

 degree, the attention, not only of those who are specially devoted to 

 astronomical and mathematical researches, but of that large and ever- 

 increasing class who are anxious for general knowledge with regard to 

 the physical phenomena of our globe. 



At first sight it might seem difficult indeed to conduct the investi- 

 gation of this question. Here is a point on the earth's surface, this 

 wonderful North Pole, which, so far as we certainly know, has never 

 yet been approached to within 400 miles, and yet we are so solicitous 

 about the position of this pole and about its movement that we demand 

 a knowledge of its whereabouts with an accuracy which at first appears 

 wholly unattainable. It sounds almost incredible when we are told 

 that a shift in the position of the North Pole to the extent of 20 yards, 

 or even 20 feet, is appreciable, notwithstanding that we have never 



