SOME SCIENTIFIC ASPECTS OF THE METEOROLOG- 

 ICAL WORK OF THE UNITED STATES ARMY. 



By ROBERT A. MILLIKAN, Ph.D., Sc.D. 

 {Read April 26, 19 19.) 



There is no more interesting illustration of the application of 

 new scientific methods to warfare than is furnished by the develop- 

 ments in meteorology during the great war. Prior to 1914 a me- 

 teorological section was not considered a necessary part of the mili- 

 tary service. No corrections had ever been made by the artillery 

 of any army for any save surface winds. Firing by the map was 

 almost unknown. No Sound-ranging Service, no Air Service and 

 no Anti-aircraft artillery had ever existed to demand aerological 

 data. 



At the time of the signing of the armistice on the western front 

 the Air Service and all the artillery were being furnished every two 

 hours with the temperature, density, wind-speed and direction, 

 taken at the surface and at various altitudes, from 100 to 500 meters 

 apart, up to 5,000 meters. Further, tables were prepared from 

 which each battery could obtain the correction suited to its trajectory 

 for the so-called ballistic wind. This is, the average wind for the 

 trajectory, weighted for the density of the air at the elevations trav- 

 ersed. Even machine guns when used for barrage work made use 

 of these ballistic-wind tables. 



In addition, daily forecasts were furnished to the armies in ac- 

 cordance with the following outline : 



A. Character of weather for each arm of the service. 



B. Winds : Surface at 2,000 m., at 5,000 m. 



C. Cloudiness including fog and haze. 



D. Height of cloud. 



E. Visibility. 



F. Rain and snow. 



G. Temperature. 



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