PRESIDENTIAL ADDRESSES. 527 



seeming to show that an augmentation took place, 

 somewhat suddenly, about the year 1890. 



When we consider how much water falls on 

 Europe and Asia during a month or two of rainy 

 season, and how many weeks or months must pass 

 before it gets to the sea, and where it has been in 

 the interval, and what has become of the air from 

 which it fell, we need not wonder that the distance 

 of the earth's axis of equilibrium of centrifugal 

 force from the instantaneous axis of rotation 

 should often vary l by five or ten metres in the 

 course of a few weeks or months. We can 

 scarcely expect, indeed, that the variation found 

 by the International Geodetic Union during the 

 year beginning June, 1891, should recur periodic- 

 ally for even as much as one or two or three times 

 of the seeming period of 385 days. 



One of the most important scientific events 

 of the past year has been Barnard's discovery, on 

 the 9th of September, of a new satellite to Jupiter. 

 On account of the extreme faintness of the object 

 it has not been observed anywhere except at the 



1 See j9nV. Assoc. Reports, 1876, Address to Section A, pp. 10, u. 



