124 BULLETIN OF THE 



In the case of the two determinations marked with a * the two 

 Diomede Islands are so represented on the chart that the boundary- 

 line is tangent to each island. 



During the past summer an attempt was made by the party on 

 board the U. 8. C. and G. S. Schooner Yukon to make a more care- 

 ful determination of the longitude of this meridian than had been 

 attempted hitherto. For longitude purposes the party had one 

 pocket and six box chronometers. For determining time the sextant 

 was used, recourse being had to equal altitudes whenever possible. 



Plover Bay in Eastern Siberia is about 150 miles to the south- 

 ward and westward from the Diomede Islands in Behring's Strait. 

 This bay was visited by Prof. Asaph Hall of the U. S. Naval obser- 

 vatory in 1869 for the purpose of observing the total solar eclipse 

 of that year, and, in connection with the eclipse work, Prof. Hall 

 made a careful determination of the longitude of his station. 

 After a careful examination of all the longitude determinations 

 known to exist, and because the facilities for determining the longi- 

 tude of this place by the Yukon party were not sufficient to im- 

 prove upon the determination by Prof. Hall, his results have been 

 adopted, and the longitude of the boundary meridian made to 

 depend upon his determination. Before proceeding to give an ac- 

 count of our longitude observations, when near the boundary line, 

 a complete resume of observations for position at Plover Bay, with 

 discussion will be given, this being rendered necessary by the fact 

 that the longitude of the boundary line as well as that of all other 

 points along the Arctic coast and northern part of Behring Sea have 

 been made by us to depend upon Plover Bay. 



Previous to 1848 Plover Bay, though an extensive arm of the 

 sea running inland some 20 to 25 miles, appears not to have been 

 known. It is not shown upon any map before 1850. In the period 

 from 1845 to 1848 it seems to have been visited by the whalers. 

 The first information touching it upon which we can lay our hands 

 is the report of Commander Moore to the Admiralty, published in 

 the Nautical Magazine March, 1850. From this it appears that 

 Commander Moore first anchored in Plover Bay, October 17, 1848 

 Later he moved his vessel, the Plover, farther in, and wintered in 

 the harbor named by him Emma Harbor. He remained in Emma 

 Harbor until June 23, 1849. Concerning the scientific or survey- 

 ing work accomplished in this period of eight months, he says ; 

 "At intervals Mr. Martin, assisted by Mr. Hooper, made a survey 



