Following American examples, L. Teisserenc de Bort. at 'frappes, near Paris, and R. Assmann, at Berlin, have systematically used the kite as a means of obtaining observations in the free air at moderate elevations. For all greater heights the balloon, especially the so-called sounding balloon, must be used. The kite can be used in windy weather when the balloon canot; but the special advantage of the former lies in the fact that the self-reco•ding apparatus is thoroughly ventilated by the wind that supports the kite, and must therefore give the temperature and moisture of the free air with the least possible error intro duced by solar heat or instrumental radiation.
The use of kites to carry lines across streams of deep chasms and to convey life-lines to stranded ships is a familiar practice in engineer ing and life-saving work. Kites have also re cently been used to hold suspended in midair banners for advertising and other purposes, and for taking photographs. For all of these pur poses, as has been stated. either Hargrave or :Nlalay tailless kites are employed. The Malay kite is well shown in the accompanying illustra tion, taken from a paper by Mr. J. B. Millet pub lished in the Aeronautical Annual for 1896; this illustration also gives Mr. Millet's notions as to the proper proportions for kites of this type.
The military use of kites has been especially developed by the Aeronautic Division of the German Army, which has adopted the balloon kite invented by Parseval and perfected by Cap tain von Sigsfeld. This consists essentially of
a cylindrical gas-bag filled with hydrogen and flown as an ordinary kite. When the wind blows, its pressure tends to keep the kite up by the re action of the cord attached to the balloon, and does not bean- it down to the ground, as in the case of a captive spherical balloon. When there is no wind, the buoyancy of the hydrogen suffices to keep the balloon up. For military purposes the balloon kite is not expected to rise more than a few hundred yards above the ground, and when in that position, a signal officer can be raised sufficiently high to scrutinize the surrounding country.
13.uitioRnAmIY. Consult: Proceedings of the In ternational Conference on .1.Cria1 rigation, held in Chicago, August 1. 2, 3, and 4, 1893; larvin, Mrehanies of the Kite; Instructions for Aerial Observations; Inrestiyalion of the Sluggishness of the .11cleorogra ph, and other bulletins of the Weather Bureau (Washington. D. C.) ; A. L. Botch and IL H. Clayton, (Thserrations at the Blue Hill flbserratory; L. Teisserene de Mort, "Etudes sur la temp6rature et sea variations," in the Annals of the Central Meteurologieul Bureau (Paris. 1897). Also: "Sur l'organisa tion des sondages acriennes," in the Memoirs of the International Congress for Meteorology (Paris, 1900); and especially: ...kssinann and Berson, •rg•bnisse der Arbeiten ann aeronauti tachen Obserratorium in den Jahren, 1900 nod 1901 (Berlin, 1902).