1909.] BY MEANS OF KITES AND BALLOONS. 9 



To those meteorologists who have sufficient leisure and the means of 

 performing such experiments, we would recommend the use of kites and 

 balloons for ascertaining the temperature and state of the upper atmosphere. 

 The Earl of Minto has obtained several very interesting results by the use 

 of balloons. 



Ten years later, Espey, in our own country, used kites to prove 

 his theory concerning cloud altitudes. He held that the base of a 

 forming summer cloud should be as many times lOO yards high as 

 the temperature of the air at the earth's surface is above the dew 

 point in degrees Fahrenheit, i. e., that these clouds form in a'Scend- 

 ing currents and that the air cools one degree Fahrenheit for every 

 100 yards it ascends. He was able to put his kite in the base of a 

 cloud i,20o yards above the earth's surface and not only proved his 

 theory within the error of observation, but found that the motion 

 of the kite in the base of the cloud showed ascending air currents. 

 He also obtained some striking electric effects, wire being used 

 instead of string to fly the kite. 



The report of the Franklin Kite Club, about 1838, on the dis- 

 covery of ascending air currents gave further proof of Espey's 

 theory and stated that this theory had the recommendation of the 

 American Philosophical Society. 



A contemporary of Espey, James Swain, flew kites for the pur- 

 pose of determining daily the height of that layer of " electrified 

 air whose positive electricity was concentrated enough to expand 

 the leaves of an electrometer." Swain used No. 30 steel wire, 

 which he wound on a reel four feet in circumference and having 

 a glass axle like the one used by the Franklin Club of Philadelphia. 

 Steel wire is now universally used in kite flying. 



In 1847 Admiral Back flew kites from the deck of his ship. The 

 Terror, and obtained free air temperatures over the ocean. 



Up to this time the kites used have been small and rather unstable 

 in their flight. Little more was done with them until Archibald, an 

 Englishman, began to look into the mechanics of kite flight in 1883. 

 In the meantime mountain stations and captive balloons were 

 further developed in an effort to get temperature readings at greater 

 altitudes than had thus far been possible. An observatory was 

 established at Mt. Washington in 1870 and one at Pike's Peak in 



