216 PROCEEDINGS OF THE AMERICAN ACADEMY. 



for meteorological researches, except during calms which sometimes occur 

 at the earth's surface, but rarely exteud aloft. 



There remain kites aud unmanned balloons, both recording graphically 

 and continuously the chief meteorological conditions, and these it is my 

 intention to describe in this paper. The recent development of the kite 

 for meteorological purposes has taken place in the United States, while 

 the use of the automatic balloon for obtaining data at very great altitudes 

 has hitherto been confined to Europe. 



Kites appear to have been first applied in meteorology by Alexander 

 Wilson, of Ghisgow, who in 1749 raised thermometers attached to the 

 kites into the clouds.* Three years later, Franklin performed in Phila- 

 delphia his celebrated experiment of collecting the electricity of the thun- 

 der-cloud by means of a kite.f Although kites haVe served a variety of 

 purposes, their first systematic use in meteorology was probably in Eng- 

 land, between 1883 and 1885, when E. D. Archibald mad« differential 

 measurements of wind velocity by anemometers raised by kites fifteen 

 hundred leet.t In 1885, A. McAdie repeated Franklin's kite experiment 

 on Blue Hill, using an electrometer,§ and in 1891 and 1892 made simul- 

 taneous measurements of electrical potential at the base of Blue Hill, 

 on the hill, and several hundred feet above it with kites as collectors. 1| 

 The invention of light-weight self-recording instruments made it possible 

 to obtain graphic records in the air by means of kites, and after W. A. 

 Eddy iiad introduced tailless kites into this country, and had attached a 

 minimum thermometer in 1891,^ a thermograph reconstructed of lighter 

 materials by S. P. Fergusson, of the Blue Hill Observatory, was raised 

 on August 4, 1894, 1430 feet above the hill.** It was no doubt the first 

 instrument, recording continuously and graphically, to be lifted by kites, 

 and it permitted simultaneous observations to be obtained in the free air 

 and near the ground. This method of studying the meteorological con- 

 ditions of the free air has ever since been in regular use at the Blue Hill 

 Observatory ; but notwithstanding the general interest which has recently 

 been aroused in kites, it is not known by the writer that meteorographs 

 have elsewhere been raised by them. 



* Trans. Roy. Soc. of Edinburgh, Vol. X. Part II., pp. 284-286. 

 t Sparks's Works of Benjamin Franklin, Vol. V. p. 295. 

 t Nature, Vol. XXXI. 



§ These Proceedings, Vol. XXI. pp. 129-134. 



II Annals Astr. Obs. Harv. Col., Vol. XL. Parts Land II., Appendices A and C 

 H Am. Met. Journal, Vol. VIII. pp. 122-125. 

 ** Il.id.,Vol. XI. pp. 297-303. 



