Until a very recent period the evidence on the subject was almost altogether negative; it was no doubt recognised that there might be some fluctuations in the position of the Pole, but it was known that they could only be extremely small, and it was believed that in all probability those fluctuations must be comprised within those slender limits which are too much affected by inevitable errors of observation to afford any reliable result. Perseverance in this interesting inquiry has at last been rewarded, and as in so many similar cases we are indebted to the labours of many independent workers for the recent extension of our knowledge. We are, however, at present most interested by the labours of Mr. Chandler, a distinguished American astronomer, who has made an exhaustive examination into the subject. The result has been to prove that the Pole does undergo movement in the body of the earth. 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 consideration an important improvement in certain delicate astronomical inquiries 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 investigation 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 within 400 miles, and yet we are so solicitous about the
