50 THE NEW WORLD OF SCIENCE 



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. 



H. Warning of weather conditions favorable for use of gas 



by enemy. 

 K. Probable accuracy or odds in favor of forecast. 



Most of the aerological data were obtained from theodolite 

 observations on pilot balloons. The extent to which our knowl- 

 edge of the upper air has been, and is being, extended by this 

 pilot balloon work may be seen from the fact that before the 

 war there existed but one station in the United States where 

 pilot balloon explorations were regularly carried on. Within 

 a year of the inception of the meteorological service in the 

 United States Army, thirty-seven complete stations for the ob- 

 taining of both surface and upper air data in aid of aviation 

 and the artillery had been established in the United States and 

 equipped with special aircraft theodolites and pilot balloons, 

 neither of which had ever been produced before in this coun- 

 try. Further, twenty such stations had been established by 

 our forces abroad. For the manning of this service, about 

 five hundred specially selected men had been trained in this 

 country, and three hundred and fourteen of them sent abroad, 

 while about two hundred were held for work in the United 

 States. 



The scientific interest in this service centers about four dis- 

 tinct problems : 



1. The extension of our knowledge of the law of motion of 

 pilot balloons. 



2. The procurement of data and the development of methods 

 for the preparation of artillery range table. 



