PHILOSOPHICAL SOCIETY OF WASHINGTON. 127 



These are the results by each chronometer, and when combined 

 by weights indicated by their probable errors, the resulting longi- 

 tude is 



h. m. s. s. 



3 24 21. 1 zh 0.36 



Since these results were published, the longitude of San Francisco 

 has been determined by telegraph, and the station upon Mare Island 

 occupied by Prof. Hall geodetically connected with this determi- 

 nation. The resulting longitude of the Mare Island station is, 

 according to Assistant Schott of the Coast Survey, 



o . / // // 



122 l6 l6 ± 2.2 



or, in time, 



h. m. s. s. 



8 09 05.07 ±0.15 



whence we have for the longitude of Prof. Hall's station, at Plover 

 Bay 



h. m. s. s. 



II 33 26.2 ± 0.4. 



For Prof. Hall's station, therefore, we adopt 



Latitude, 64 22 7 25" N. 



Longitude, 173 21 33 ± 6" W. Gr. 



Before leaving Washington we were furnished by Prof. Hall with a 

 memorandum, describing his station from which it appears that no 

 permanent station mark could be left by him, the character of the soil 

 and natives preventing this. We were, therefore, unable to locate 

 the exact spot, but had no difficulty in finding the general locality, 

 and fixing upon a place that must have been within a few metres 



