78 OUR PHYSICAL WORLD 



characterized the attempts to utilize the air as a means of further- 

 ing his purposes: (i) to harness the winds to provide power for 

 his machines; (2) to use the air as a medium of transportation. 

 Under the first heading may be mentioned windmills and sail 

 boats; under the second, kites, aeroplanes, and balloons. 



Who the inventive genius was who first devised and flew a 

 kite we do not know. But probably it was some Chinaman, 

 for kites have been known in China and Malaysia for a very long 

 time, even before historic times; they are used there for decora- 

 tive effects at the numerous festivals. Not only the tailed 

 variety but also the tailless sorts are made, and these latter of 

 many curious designs fish, birds, and geometrical figures of 

 pleasing shapes. 



Kites have been largely playthings for the race until very 

 recent times, although occasionally some keen ancient mind 

 caught sight of their serious uses. 



The first really serious use of kites that is historically authentic 

 occurred in 1749 when Dr. Alexander Wilson, an Englishman, 

 and Thomas Melville, an American, raised kites high up in the air 

 with thermometers attached to them to get the temperature of 

 the upper air. Since then kites have been used extensively for 

 carrying up thermometers, barometers, hygrometers, anemom- 

 eters, and other scientific instruments to get records of the 

 conditions up among the clouds. Such facts are of service in a 

 better understanding of the sudden changes and probable condi- 

 tions of the weather. Many of the United States Weather 

 Bureau stations are provided with kites which are regularly flown, 

 carrying up self-registering instruments to collect data. Kites 

 have been sent for such purposes so high that the recording 

 instruments showed a barometric pressure of only 4 inches and a 

 temperature of 87 C. Remembering that the air pressure at 

 sea-level is about 30 inches on an average, it is evident that the 

 kite had soared well above the great bulk of the air. 



Kites have been used to take up cameras to get a bird's-eye 

 view of the underlying territory, to lift men as observers, and 



