THE EXPLORATION OF THE FREE AIR BY MEANS OF KITES 

 " AT BLUE HILL OBSERVATORY, MASSACHUSETTS. 



By A. Lawrence Rotch, Director. 



The first use of kites for scientific purposes, so far as is known, was 

 in 1749 when Dr. Alexander Wilson and his pupil Thomas Melville, of 

 Glasgow, raised thermometers attached to kites into the clouds.^ Three 

 years later BenjaDiin Franklin performed, in Philadelphia, his celebra- 

 ted experiment of collecting the electricity of the thunderstorm by 

 means of a kite.'^ During the first part of the present century kites 

 were used in Europe to carry thermometers into the air, and about 

 1840 Espy, in this country, employed kites to verify calculations of the 

 height of clouds by means of the dew-point.^ 



Modern kiteflying for scientific purposes may be said to date from 

 1883, when Douglas Archibald, in England, fastened to the kite wire 

 anemometers which registered the total wind movements on dials, and 

 so obtained differential measures of wind velocity at heights up to 1,200 

 feet.* In 1885 Alexander McAdie (now of the United States Weather 

 Bureau) repeated Franklin's experiments on Blue Hill, using an elec- 

 trometer,'^ and in 1891 and 1892 he measured, simultaneously, the elec- 

 tric potential at the base of Blue Hill, on the hill, and with kites as 

 collectors, several hundred feet above the hilltop. About the same 

 time L. Weber in Breslau, Germany, made a more extended use of kites 

 to collect atmospheric electricity.*^ 



To William A. Eddy, of Bayonne, N. J., is due the credit of again 

 turning the attention of scientific men to kiteflying, and thus causing, 

 the widespread interest in it which now exists. About 1890 Mr. Eddy 

 used an ordinary kite to lift thermometers, but soon afterwards devised 

 a tailless kite which resembled the kite flown in Java. This kite has 

 the ends of its horizontal cross stick bent backward, and the convex 

 surface exposed to the wind obviates the necessity of a tail and 



1 Trans. Roy. Soc. of Edin., Vol. X, Part II, pages 284-286. 



2 Spai'ks's Works of Franklin, Vol. V, page 295. 

 ^Espy's Philosophy of Storms, page 75. 

 ^Nature, Vol. XXXI. 



sProc. Am. Acad. Arts and Sci., Vol. XXI, pages 129-134. 



•> Electrotechnische Zeitschrift, November, 1886; August, 1889. 



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