ON OBTAINING METEOROLOGICAL RECORDS IN THE 



UPPER AIR BY MEANS OF KITES AND 



BALLOONS. 



By a. Lawrence Rotch. 



Presented January 13, 1897. 



A KNOWLEDGE of the pliysical conditions which prevail up to the 

 highest cIo«d levels, live to nine miles above the earth, is of great im- 

 portance to meteorologists, who until recently have been studying prin- 

 cipally the conditions existing near the floor of the aerial ocean, and 

 from that standpoint have endeavored to formulate the laws which 

 control the i^ressure, temperature, humidity, and currents in the great 

 volume of air above them. Continued and systematic observations on 

 mountains in different parts of the world latterly have contributed 

 much to our knowledge of the approximate conditions of the atmosphere, 

 under various circumstances, up to a height of more than three miles 

 above sea level, but the mass and surface of the mountain, even when 

 this is an isolated peak, influence very considerably the surrounding 

 air. Recognizing, then, the value of the determination of the true 

 conditions of the free air, let us consider what methods are available 

 for this investigation, which must necessarily be sporadic and of shorter 

 duration than if conducted on mountains. In the writer's opinion, free 

 balloons with aeronauts cannot be recommended on account of the large 

 cost in money, and sometimes the loss of life, which attend their frequent 

 use, while without artificial aids to respiration the aeronaut cannot rise 

 much above five miles. Captive balloons, with observers, have been 

 used in England, and more recently, with self-recording instruments, 

 in Germany, but their height is limited to about two thousand feet by 

 the weight of the lifted cable, and a wind which is sufficient to overcome 

 tlieir buoyancy drives them down and occasions violent shocks to the sus- 

 pended instruments. A kite-balloon on trial in the German army is 

 intended to combine the advantages of a kite and a balloon, but the cost 

 and the moderate height attainable render it inferior to the simple kite 



