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SCIENCE 



[N. S. Vol. XXV. No. 648 



Professor Hergesell reported on the 

 progress of the work which the commission 

 furthers, since its meeting at St. Peters- 

 burg in 1904. In Spain unique observa- 

 tions had been obtained with balloons dur- 

 ing the total solar eclipse of August 30, 

 1905; two expeditions had been sent from 

 France by Messrs. Teisserenc de Bort and 

 Rotch to explore the atmosphere above the 

 tropical Atlantic; in Italy manned and 

 registration balloons at Rome, Pavia and 

 Castelfranco had contributed data, while 

 kites had been employed in the vicinity of 

 Monte Rosa; in Russia the observatory at 

 Pawlowsk was making aerial soundings and 

 other stations were being equipped for this 

 purpose; in Switzerland Dr. Maurer had 

 compared the data on mountains with those 

 in balloons and in Austria numerous scien- 

 tific balloon ascensions had taken place. 

 In Great Britain and India kite flights were 

 being made and in the United States the 

 government Weather Bureau had joined 

 the Blue Hill Observatory in making kite 

 flights on the term-days. Germany was 

 very active: there were daily observations 

 in the free air at Lindenberg and Hamburg, 

 and in Munich Baron von Bassus and Pro- 

 fessor Ebert were experimenting with bal- 

 loons ; the money for a floating observatory 

 on Lake Constance was assured, so that 

 ascents of balloons or kites would eventu- 

 ally be made from a fast steamer; the 

 German Marine had sent a surveying ship, 

 equipped also with apparatus for exploring 

 the air, into the tropics, and the Prince of 

 Monaco, with the cooperation of the speak- 

 er, had executed such explorations over the 

 Mediterranean, and over the tropical At- 

 lantic and Arctic oceans. Belgium was 

 now participating in the despatch of ial- 

 lons-sondes and Roumania had promised to 

 cooperate. The cost of publishing these 

 observations executed in the free air, 

 amounting to about 12,000 francs a year, 



is defrayed by the countries which collect 

 them. General Rykatchef, in reporting on 

 the resolutions adopted at St. Petersburg, 

 stated that it had not been possible to 

 secure the free entry into the different 

 countries of the balloons and instruments 

 which were used in the experiments. 



The topics discussed in the subsequent 

 sessions related to the methods of investi- 

 gation or the results obtained and a sum- 

 mary of the most important follows. Dr. 

 Erk, of Munich, advocated balloon ascen- 

 sions in the neighborhood of the Alps in 

 order to study local phenomena, such as 

 the fohn wind. Professor Ebert indicated 

 the methods which he employed to deter- 

 mine the deformation of equipotential elec- 

 trical surfaces around a balloon and showed 

 a new apparatus to measure atmospheric 

 ionization. 



The use of small balloons to determine 

 the currents in the high atmosphere was 

 discussed by Dr. de Quervain and others. 

 If a barometer is carried by the balloon 

 from its trace and from the measured 

 angles of the balloon the course can be plot- 

 ted. A small balloon may be observed 

 with a telescope to a height of ten or twelve 

 kilometers and Professor Hergesell was 

 able in the clear air of Spitzbergen to fol- 

 low a rubber balloon, which expanded to 

 one and a half meters in diameter, during 

 seventy-four minutes, at the end of this 

 time the balloon being eighty kilometers 

 distant. Micrometric measurements of its 

 diameter showed the velocity of ascent to 

 be nearly constant, since the loss of gas is 

 slight, so that the height when it enters the 

 difl:erent currents may be calculated from 

 a single station, even if the balloon carries 

 no barometer or is not recovered. A 

 mechanical triangulating device has been 

 used by De Quervain for finding the height 

 of the balloon, but this is similar to the 

 apparatus which Mr. Clayton devised for 



