Miscellaneous Intelligence. 439 



that there is a secular change extending over a period of at least 

 sixty years. 



It is evident that if observations on opposite sides of the earth 

 show opposite phases, that is to say, if the Hawaiian Islands ap- 

 proach the equator at the same time that places in Europe recede 

 from it, there is a strong presumption that the phenomenon is not 

 a purely local one, but results from a real motion of the pole, af- 

 fecting all places on the earth's surface. Indeed this latter fact 

 now seems to be conclusively demonstrated from the observations 

 up to date. 



The method of work consists in observing, on every clear night, 

 a list of stars in pairs whose positions are very well known; pref- 

 erence being given, other things being equal, to ones that were 

 observed in England more than one hundred years ago, and 

 whose motion since that time is therefore well determined. The 

 stars, as far as they relate to the latitude work, were adopted in 

 Berlin, and their selection was made the subject of careful study. 

 In order to get the best possible result, certain relations must 

 exist between the stars chosen, and this complicates the problem 

 and makes their selection correspondingly difficult. For instance, 

 in order that refraction may be small, nothing is taken beyond, 

 say, 25 degTees from the zenith. In order that the image of the 

 star be fine and well defined, only faint stars are admitted ; and 

 stars composing the same pair must be of about the same magni- 

 tude. Besides, if there is a certain relation between the distances 

 of the stars from the zenith, the result is entirely free from any 

 effect arising from an imperfect knowledge of the measuring appa- 

 ratus. It is very desirable for several reasons to eliminate this 

 effect. Then, again, the stars must not succeed each other too 

 rapidly, in order that the measurements be carefully and deliber- 

 ately made, nor on the other hand must they be too far apart. 

 All these conditions should be satisfied at the same time, as far 

 as practicable, which makes the selection of a perfect list of stars 

 a somewhat tedious operation. 



The great degree of refinement to which observations of this 

 class are now brought, may be judged from the fact that although 

 the observatories at Waikiki are only about thirty feet apart, this 

 distance has a very perceptible effect on the result, and the obser- 

 vations continually show a difference of just this amount in the 

 determined latitudes. However, for the study of the law of 

 change of latitude, this is of no moment, for whatever the relative 

 position of the points of observation they both change equally and 

 verify the same law. The method employed, which is known as 

 that of equal zenith distances, was first practically developed in 

 the United States Coast Survey and is now universally adopted 

 in work of this kind. 



When the government at Washington was asked to cooperate 

 in the Honolulu observations, it was seen that the occasion would 

 be a favorable one for the study of several kindred subjects and 

 the American representative in addition to the international lati- 



