16-i Scientific Intelligence. 



smaller by about 0' ;, 2 than those observed at the same season in 

 1889. 



The well-known theoretical period of ten months, originally 

 deduced by Euler, had been shown successively by Peters, Nyren 

 and Newcomb, after careful comparison of various series of obser- 

 vations, to manifest little or no trace of real existence. The 

 supposed secular changes, on which Fergola, supported by 

 Schiaparelli, had based propositions for further investigation, had. 

 similarly been shown by Prof. Hall to be questionable. Later, 

 Radau and Helmert published researches, in which it was pointed 

 out that, an epicyclical combination of the ten-months' period 

 with one of several years' duration, commensurable with it, 

 would give a resultant inequality of the latitude having a period 

 of from eleven to fifteen months, and the particular character of 

 which would depend on the coefficients assumed. 



The observed variations of latitude might of course be ex- 

 plained by a change either in the position of the zenith or in that 

 of the pole. To decide this question, as well as to confirm or dis- 

 prove the assumption that the observed motion is common to the 

 whole globe, the Geodetic Association equipped and sent out an 

 expedition to establish a station at Honolulu, a point differing by 

 about 180° in longitude from the region in which the German 

 observations had already been made. The observer, Dr. Marcuse, 

 was instructed to make continual determinations of the latitude, 

 by Talcott's method, for a full year. And, that the determina- 

 tions might be fully confirmed, the U. S. Coast and Geodetic 

 Survey was invited also to send an observer, with another instru- 

 ment, to the same place,— an invitation which an appropriation 

 from the Bache fund of the National Academy enabled the 

 Superintendent to accept. Accordingly he deputed Mr. Preston, 

 an experienced assistant of the Survey, to make these inde- 

 pendent determinations. Meanwhile the observations in Europe, 

 were continued, and with mutually confirmatory results. More- 

 over Dr. Nyren brought to the Astronomical Congress at Munich, 

 in August last, a series of latitude-determinations made at 

 Pulkowa, which exhibited variations closely parallel to those 

 simultaneously made at the German observatories. 



Tne original observations of Dr. Marcuse at Honolulu were 

 sent to the Central Bureau at Berlin, in monthly installments, and 

 were computed there. At the close of September last, three 

 months' observations had been fully computed, and the result 

 found that, while the changes were entirely accordant in magni- 

 tude with the European ones, they were in the opposite direction. 

 This might at first be supposed to imply an actual tilting of the 

 earth's axis, corresponding to a change in position of the celestial 

 pole. But this appears not to be the case, for, although the dis- 

 tance between the zenith and the pole is thus seen to have dimin- 

 ished in one place, while it increased at the otber, on the opposite 

 side of the earth, the interpretation mentioned is excluded by 

 the important fact that identical stars were employed for the 



