298 GEOGRAPHIC WORK OF THE U. S. COAST SURVEY 



Grand in its inception, splendid in its execution, this monu- 

 mental work may be reckoned as the most important contribu- 

 tion to the geography of our country, on account of its present 

 and prospective value. The measurement of a great meridional 

 arc along the 98th meridian is in contemplation, and our sister 

 Republic of Mexico, which has just established a Geodetic Sur- 

 \ey, it is hoped will take a hand in its extension southward, 

 while to our cousins across the northern border a similar oppor- 

 tunity for its prolongation northward may be offered in the 

 course of time. 



The Survey has been especiall}^ called upon for assistance in 

 defining the boundaries of eleven States, and aid has been ex- 

 tended to fifteen others by the determination of geographical 

 positions within their borders. In the determination of the na- 

 tional boundaries it has cooperated in retracing the line between 

 Mexico and the United States, has made topographic surveys 

 along the northeastern boundary, and in the far north it has 

 determined the crossing of the I41st meridian on the Porcupine 

 and Yukon rivers in regions to which all adventurous eyes are 

 now turned, and in southeast Alaska it has made exploratory 

 sui'veys, as well as precise geographic determinations, for the 

 ultimate delineation of the bpundaiy between Alaska and the 

 British possessions. 



The enormous extent of the country included in the operations 

 of the Survey, and especially its nearness to the principal north 

 magnetic pole, offered a rare opportunity for the investigation of 

 the problem of terrestrial magnetism. Observations began at an 

 early date, and have been continued up to the present time at a 

 constantly increasing number of stations. In addition to a regu- 

 lar, periodic study of the magnetic elements at a large number 

 of specially selected points by the most approved methods and 

 the best of instrumental appliances, the Survey has maintained 

 a photographic registering magnetic observatory, which it has 

 moved from time to time from one part of the country to another. 

 It has made extensive publication of the data thus obtained, in- 

 cluding a series of magnetic charts which are of the greatest 

 value to navigators at sea and surveyors on the land. Its archives 

 contain a mass of reliable information concerning terrestrial 

 magnetism unequaled in extent and importance. 



In common with several similar organizations in Europe, it 

 has devoted much attention, mostly during the past twenty-five 

 years, to the study of terrestrial gravity. Beginning with methods 



