IV 



SOME SCIENTIFIC ASPECTS OF THE METEORO- 

 LOGICAL WORK OF THE UNITED STATES ARMY l 



ROBERT A. MILLIKAN 



THERE is no more interesting illustration of the applica- 

 tion of new scientific methods to warfare than is fur- 

 nished by the developments in meteorology during the great 

 war. Prior to 1914 a meteorological section was not con- 

 sidered a necessary part of the military service. No correc- 

 tions 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 cor- 

 rection 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 traversed. 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 

 accordance with the following outline : 



1 Reprinted by permission, with the omission of certain illustrations, 

 from the Proceedings American Philosophical Society, vol. 38, 1919. 



49 



