144 MILLIKAN— METEOROLOGICAL WORK 



the winds both over western Europe and over the United States 

 blow from west to east (i.e., have a westerly component), Captain 

 Sherry in 1917 suggested the development of a large program for 

 the extension of the use of pilot balloons for the purpose of flooding 

 the whole of Germany and Austria with propaganda dropped from 

 such balloons. The project was submitted to the meteorological 

 and military agencies in France and pronounced infeasible, chiefly 

 because the rapid diffusion of hydrogen through rubber had hereto- 

 fore rendered it impossible to obtain pilot balloon flights of more 

 than about 100 miles. Undiscouraged, however, by these reports. 

 Mr. W. J. Lester, Dr. S. R. Williams and Sergeant Redman attacked 

 the problem of extending the range of pilot balloon flights by de- 

 veloping an automatic ballast-control and by reducing the diffusion 

 by means of a special dope. 



The automatic control was ingeniously simple, its essential fea- 

 ture being a belly band which kept the girth of the balloon constant 

 (at a diameter of four feet) through the discharge, in the act of 

 shrinking, of a few drops of kerosene, thus causing reascension and 

 consequent expansion. 



With this device the balloon not only does not fall but rises very 

 gradually to higher and higher levels until its ballast of kerosene 

 or alcohol is exhausted. 



In the week beginning October 3, 1918, sixty such balloons, ad- 

 justed to fly between the initial and final altitudes of 15,000 and 

 25,000 feet respectively were sent up from Fort Omaha, Nebraska, 

 carrying return cards and watches, which were arranged to stop and 

 be let down on small parachutes as soon as the ballast was ex- 

 hausted. Thirty-four out of sixty of these balloons were picked 

 up and returned to Washington. Instead of flying 100 miles, one 

 of them came down within ten miles of New York, 1,100 miles 

 from Fort Omaha, another was returned from Virginia, 930 miles 

 from its starting point, and the rest were scattered over Ohio, Ken- 

 tucky, Illinois, Wisconsin and Iowa. Not one went west of Omaha 

 though the balloons were sent up on days on which different surface 

 conditions prevailed. 



The credit for this achievement, the significance of which will 

 be discussed later, is due primarily to Mr. Lester, Captain Sherry, 



