190 THE PROGRESS OF AERONAUTICS. 



observer has to contend with the hick of pressure of the air, which 

 causes an expansion of all the gases contained in his bod}', and, not- 

 withstanding the respiratory reparation by oxj^gen, the expansion may 

 kill the man. Other means nmst therefore be employed to carry the 

 investigations of science to much greater altitudes. Since the 188!» 

 congress, the plan of Le Monnier has been realized of sending up bal- 

 loons by themselves with self-registering apparatus. Here, too, there 

 is a limit to the attainable height, but it is nuich greater than that 

 of balloons carrying men. We owe to Lieutenant-Colonel Renard 

 excellent studies and advice for constructing and managing such bal- 

 loons and to Messrs. Hermite and Besancon their tirst employment in 

 France. The success of these first trials and of the studies made by 

 means of them, especially b}' Messrs. Violle and Cailletet, was such 

 as to lead to the appointment of an international commission repre- 

 senting almost every European nation, and this commission is now 

 holding a meeting in Paris under the presidency of Mr. Hergesel. It 

 is eas}^ to see that these aerial soundings, if ore ma}^ call them so, 

 become infinitely more interesting when the}^ are made sinudtaneously 

 from stations throughout a region of the earth. * 



But l)alloons are now no longer the only instruraimts employed for 

 meteorological researches. The highly ingenious plan of using kites 

 is also put into practice. These little instruments, which in China and 

 in ancient India were accessories of public spectacles, have become, in 

 the hands of our meteorologist, in imitation of Franklin, serious scien- 

 tific apparatus. We have lately l)een informed that Mr. Kotch, a 

 highly distinguished American meteorologist, has succeeded in flying- 

 one of these apparatus carrying his self-registers to a height of 15,800 

 feet (4,815 meters), little short of that of Mont Blanc. M. Teisserenc 

 de Bort, our devoted colleague, who has kindly consented to give a lec- 

 ture to the congress, has founded out of his contributions at Trappes, 

 not far from the old house of Port Royal, an exceedingly interesting 

 observatory, where meteorology is studied '\>y widely various means, 

 and where kites are likewise emploj^ed. One of them has lately risen 

 to 16,900 feet (5,150 meters). In Berlin, too, at the Meteorological 

 Institute, a new service has been instituted in which kites, both alone 

 and combined with a })alloon, are employed for the observation of 

 atmospheric phenomena. 



It was natural that balloons, which are only rendered possible by the 

 atmosphere, should at tirst be used for the study of the atmosphere. 

 But now they l)egin to look higher, and the heavens will confer upon 

 them a new and honorable office. For while there are astronomical 

 investigations which require great instruments of the utmost stability, 

 there is another class of phenomena which onl}^ need to be noted 

 as taking place. Of this num])er are, for example, the apparitions 

 of comets, shooting stars, and eclipses. This extremely interesting 



