GEOGRAPHY. 



By Commander F. M. Green, U. S. N. 



While the area of unexplored regions of the earth's surface does not 

 seem to have been materially decreased during 1883, a large amount of 

 knowledge has been derived from the labors of travelers, explorers, 

 and surveyors during that time. 



Among the problems affecting geography in general the one to which 

 the most attention has been drawn during the last year is that of a 

 common prime meridian or the selection of a point from which all nations 

 shall agree to reckon longitude. Strange as it may appear, sentimental 

 considerations seem to have had a large share in forming the opinions 

 expressed on this subject, and no plan appears to have met with such 

 general approval as that of drawing the prime meridian through some 

 point in the ocean away from the capital of any country, so that no 

 national susceptibilities need be offended. It would seem that a very 

 few words should serve to dispel such an idea. As longitudes are now 

 measured, the starting point must be either a portable or permanent 

 observatory, connected with a telegraphic system of cables and shore 

 lines, in order that the local times of various places may be telegraph- 

 ically compared. These conditions would be impossible with a prime 

 meridian in the middle of the Pacific or the Atlantic Ocean, while they 

 are completely fulfilled at Greenwich, where by the tacit or expressed 

 consent of nearly all nations the prime meridian is now placed. 



At the seventh general conference of the International Geodetic 

 Association, held at Eome, October 23, 1883, it was formally resolved to 

 propose to the Governments interested to select for the initial meridian 

 that of Greenwich, defined by a point midway between the two pillars 

 of the transit circle of the Royal Observatory. 



An international convention, called, at the instance of the United 

 States Government, will meet at Washington in the autumn of 1884 to 

 endeavor to agree upon this or some other prime meridian. 



Pendulum observations of the force of gravity as a factor in the in- 

 vestigations of the figure of the earth have been continued by officers 

 of the United States Coast Survey. In the United States the princi- 

 pal stations at which pendulums have been oscillated are Albany, Ho- 

 boken, Baltimore, Washington, Saint Augustine, and San Francisco. 

 The three invariable pendulums previously swung at Greenwich, Kew, 

 H. Mis. 69 30 465 



