Um TED ST A TES DA ILY A TMOSPHERIC S UR VE Y 299 



long in use,- its observers were quick to detect and point out cer- 

 tain serious and liitherto unsus]iected faults, necessitating con- 

 siderable corrections in nearly all accumulated data relating to 

 that subject. Instruments were also improved and methods 

 greatly changed, increasing at once the precision and rapidity 

 of gravity measurements. Expeditions have been sent to various 

 quarters of the globe for the purpose of gravity observations, and 

 Coast Survey pendulums have swung in all continents except 

 Australia, in most important cities, on several of the highest 

 mountains, and on many islands in the several oceans. No 

 others have been vibrated so near the pole as these and none over 

 so wide a range in longitude. The results of these operations, 

 together with the measurement of the great arc of unrivaled 

 length, form a contribution of no ordinary interest to the more 

 precise solution of the great problems of dimensional geography. 



UNITED STATES DAILY ATMOSPHERIC SURVEY* 



By Prof. Willis L. Moore, 

 Chief of the U. S. WeaiJter Baveau 



The United States Weather Service has been in existence 

 twenty-seven years. During the past twenty-five years the daily 

 synoptic charts of the service have shown tliemost comprehen- 

 sive atmospheric survey ever presented to the forecaster or to 

 the broad investigator of the fundamental principles of storms. 

 The vast region now brought under the dominion of bi-daily 

 synchronous observations embraces an area extending 2,000 

 miles north and south, 3,000 miles east and west, and so. fortu- 

 nately located in the interest of the meteorologist as to cut an 

 important arc from the circumpolar thoroughfare of storms of 

 the northern hemisphere. The extreme points of observation 

 are Edmonton, in the Canadian Province of Alberta, on the 

 northwest ; St Johns, on the northeast ; Key West, on the south- 

 east, and San Diego, on the southwest ; and arrangements are 

 now complete for a cooperation with Mexico similar to that in 

 operation with Canada, which will in a few months extend the 

 area of observation southward over Mexico and Yucatan. 



It is a wonderful panoramic i)icture of atmospheric condi- 



*Read before the Geographical Section of the British Association for the Advance- 

 ment of Science, Toronto, August 23, 1897. 



