78 REPORTS ON THE STATE OF SCIENCE. 
was established in Egypt,! and about the same time a station, at which 
daily ascents were to be made, was equipped at Glossop in England.’ 
The upper air observations obtained at the English stations, viz., Pyrton 
Hill, Glossop, Ditcham Park, and Brighton, are published in the Weekly 
Weather Report of the Meteorological Office. 
Ballons-Sondes.—The use of small free balloons to raise self-recording 
meteorological instruments was proposed in Copenhagen as far back as 
1809.3 At that time, however, no satisfactory self-recording instruments 
were available and the idea was not taken up. It was revived in 1873 
and 1874 by Jobert and Le Verrier, who proposed in this way to test 
barometer-height formule,‘ and again by Mendeléef at the International 
Meteorological Congress at Rome, 1879.° It was not until self-recording 
instruments had been considerably improved, however, that satisfactory 
observations became possible, and Hermite in 1893 was the first to put 
the idea into practical form. Satisfactory ascents were made by means 
of a varnished paper balloon, ‘ L’Aérophile,’ filled with coal-gas, but on 
the bursting of this it was resolved to construct a balloon of goldbeater’s 
skin. With this second ‘ aérophile,’ whose capacity was 113 cubic metres 
and weight 14 kgm., ten ascents were made by MM. Hermite and 
Besangon between 1893 and 1898.° In 1893 also Prof. Hazen attempted 
similar experiments in America.’? The objection was raised that the 
results obtained in this way were subject to the same errors due to insola- 
tion as those of Glaisher m 1861-69. Consequently a silk balloon, the 
‘Cirrus,’ capacity 250 cubic metres and weight 42 kem., was constructed 
and made eight ascents from Berlin between July 1894 and June 1897. 
All the instruments were enclosed in an aspirated tube (a ‘ Urania Pillar’), 
designed by Assmann. The highest ascent of the ‘Cirrus’ was made 
in September 1894, when the pressure fell to 50 mm. at 18,500 m. and 
the minimum temperature was —67° C. 
During the progress of the German experiments negotiations were 
carried on to obtain the general acceptance of uniform methods of ob- 
servation and the interchange of instruments with a view to evolving 
the best possible type. In consequence the International Meteorological 
Conference at Paris, September 1896, appointed a committee, consisting 
of de Fonvielle, Hermite, Assmann, Erk, Hergesell, Pomortzeff, and 
Rotch, to organise a series of simultaneous international ascents.'° 
These ascents extended rapidly, and already in 1896 four manned and 
four registering balloons were sent up on the same dates from France, 
Germany, and Russia.'! In 1898 the ascents were extended to Austria 
and Italy, in 1899 to Belgium, and in 1901 to England. 
Besides the work done in connection with the International Com- 
mittee, extended series of ballons-sondes ascents were undertaken inde- 
pendently. Between April 1898 and 1902 Teisserenc de Bort sent up 
258 ballons-sondes, which attained heights of 11 km.,!? and similar 
' Quart. Jowrn. BR. Met. Soc., 1908, p. 259. * Brit. Assoc. Reports, 1907. 
8 Ann. Harvard Obs., \xviii. part I, p.1; History and Practice of Aéronautics, 
John Wise, 1850. : 
* Nature, x\viii. p. 160; Ann. Harvard Obs., \xviii. part I, p. 1. 
5 Quart. Jowrn. R. Met. Soc., 1897. 
° Compt. rend., 1896, p. 961; 1897, pp. 424, 1180; Acad. des Sciences, April 15, 
1896; 7 Aérophile, vol. i., No. 1 et seg. 1893. 
7 Ann. Harvard Obs., \xviii. part I, p. 2. 
8 Nature, vol. li. ® Thbid., vol. lvi. p. 602. 
10 Thid. 1 Thid. 
Compt. rend., 129, pp. 417-420; 141, pp. 153-155 ; Suc. Franc. Phys. Séances, 8, 
1899, pp. 126-135. 
