WEATHER BUREAU. 79 



AEROLOGICAL INVESTIGATIONS. 



KITE STATIONS. 



Freo-air observiitions by means of kites have been continued 

 throii<iliout the year at Broken Arrow, Okla. ; Drexel, Nebr. : Ellen- 

 dale, X. Dak.; Groesbeck, Tex.; Leesbiu-fr. (ira. ; and Royal Center, 

 Ind. These observations include daily kite flights and, whenever 

 possible, continuous series of flights covering periods of 24 to 36 

 hours. Records of air pressure, temperature, humidity, and wind 

 direction and speed are thus obtained. Brief summaries are tele- 

 graphed daily to the central office and other district forecast centers. 



PILOT BALLOON' STATIONS. 



Observations by means of pilot balloons were continued at five 

 of the kite stations (all except Drexel, Xebr.), and at Ithaca, X. Y.; 

 Lansing, ]Mich. ; Madison, Wis., and Washington, D. C. Early in 

 the fiscal year this work was organized also at Burlington, Vt., and 

 Denver, Colo. These observations are made twice daily, and the 

 indicated wind conditions at various heights are telegraphed to the 

 central office and other district forecast centers for use in furnishing 

 advices to the military, naval, and postal aviation services. For the 

 most part the balloons are assumed to have a constant rate of ascent 

 and are followed with one theodolite only. In order to check the 

 accuracy of the ascensional rate formula, however, observations are 

 made with two theodolites, whenever opportunity offers, at the five 

 kite stations. 



WEST INDIAN HURRICANE SERVICE. 



In order to add to our knowledge of the origin, direction, and speed 

 of movement of hurricanes, plans were made late in the fiscal year 

 to organize an aerological service in the West Indies for the period 

 Jul}' to X'^ovembor, 1920, inclusive. Owing to the limited funds avail- 

 able, observations were undertaken by the Weather Bureau at two 

 new stations only, viz, at Key West, Fla., and San Juan, P. R. 

 These. hoAvever, together with similar stations organized by the Xavy 

 at Coco Solo, Canal Zone, and Santo Domingo, Dominican Republic, 

 and several already in operation in the Gulf States, form a network 

 of stations which, it is believed, will furnish information of much 

 aid in the study of these destructive storms and in forecasting their 

 direction and rate of movement. It is to be hoped that this service 

 may be greatly extended during the next two or three years. 



COOPERATION. 



Throughout the year cooperation with the' Army and X^'avy 

 meteorological services has not only been maintaineil but has been 

 rendered considerably more efTective than heretofore. In addition 

 to the two balloon stations established by the Navy in the West 

 Indies, already referred to, about a dozen similar stations are 

 operated by these two services in various parts of the United States. 

 These stations are so distiii)uted witii respect to those of the AVeather 

 Bureau that the countrv east of the one hundredth meridian is well 



