68 MOUNTAIN OBSERVATORIES IN AMERICA AND EUROPE, 



The balloon used by M. Hermite was made of goldbeater's skin 

 — an extremely light material. A balloon of this construction, filled 

 with 25,000 cubic feet of hydrogen, will, it is said, keep one man afloat 

 for thirty days. Ordinary balloons have contained 100,000 or more 

 cubic feet of (illuminating) gas, but they are not suitable for prolonged 

 voyages. M. Hermite's balloon held about 4000 cubic feet, but it 

 was filled with coal gas on this occasion. At the start the balloon had 

 a lifting power of 143 pounds. 



The balloon started from Paris at 12 h. 25 m. (noon), and after six 

 and three quarter hours landed seventy-eight miles distant. The self- 

 registers recorded automatically every five minutes. At 2.30 P.M. the 

 balloon reached a height of 52,500 feet (nearly ten miles), and the 

 thermometer was at — 104° F. A table of the rate of decrease of tem- 

 perature with increased height has been deduced from the observations, 

 and it is very important. It is not necessary to quote this table here. 

 It shows that the rate of change is more rapid near the earth than \n 

 the upper air. The average decrease of temperature was 1° F. per 313 

 feet. 



Dr. Assmann of Berlin has also experimeDted with small balloons 

 carrying self -registering meteorological instruments, and during the 

 months May-July, 1894, several successful ascensions were made. 

 The readings of the barometer were photographed. On July 7, 1894, 

 the balloon reached an altitude of 53,560 feet, or over ten statute 

 miles. 



The greatest height so far reached by such balloons is 18,450 metres, 

 eleven and a half miles. Balloon ascents for scientific purposes are 

 regularly made in Berlin, using large balloons carrying one or two 

 persons. Heights of 10,000-13,000 feet are frequently attained, and 

 the military balloons of the German army are frequently employed in 

 these ascensions. A famous ascent was made in the Phoenix ballo<^)n 

 by Dr. Berson (December 4, 1894), starting from Strassfurt at 10.28 a.m. 

 At 4200 metres unusual fatigue was felt after exertion ; at 6000 metres 

 slight malaise ; at 6750 metres the breathing of pure oxygen gave re- 

 lief ; above 8000 metres (26,247 feet) oxygen was breathed constantly. 

 Without it dangerous symptoms of dizziness and weakness manifested 

 themselves. The highest point reached was 9150 metres (30,02() 

 feet), at 12.45 p.m. The observer's general condition was good, and 

 his opinion is that he could have gone higher had his store of ballast 

 permitted. The only serious hardship was the extreme cold, — 47°. 9 C. 

 = — 54°.2 F. At 3.45 p.m. the balloon was brought to earth near Kiel, 

 tbus ending a successful journey — the highest recorded altitude having 

 been reached. 



The scientific problems to be solved by sucli voyages are manifold. 



