298 



SCIENCE. 



[N. S. Vol. XVI. No. 399. 



torn, has the disadvantage of rising moi'e 

 and more slowly as it approaches its culmi- 

 nating point, and, consequently, the tem- 

 peratures registered are influenced by in- 

 solation to an unknown amount. Closed 

 balloons of expansible material, however, 

 rise with a constantly increasing velocity 

 until they burst, thus insuring sufficient 

 ventilation of the instruments. A para- 

 chute moderates their fall, so that they 

 reach the earth without injury. The small 

 size of the rubber balloon and the moderate 

 quantity of hydrogen gas needed is an 

 advantage as regards both cost and ease of 

 manipulation. Such a balloon, holding at 

 the start about one cubic meter of gas, 

 weighs only 380 grams, or, with the instru- 

 ment, 500 grams. A balloon formed by 

 dipping a mold into a solution of india- 

 rubber, was expanded to 68 times its origi- 

 nal volume before it burst, which indicated 

 that it would rise to an altitude of about 

 38 kilometers. The subject of sensitive ther- 

 mometers for hallons sondes was opened 

 with an account of some tests by Dr. 

 Valentin, of Vienna. M. Teisserenc de Bort 

 exhibited a thermograph in which the Bour- 

 don tube was insulated by a piece of hard 

 rubber and Dr. Hergesell showed another 

 instrument in which a curved metal tube 

 transmitted its changes of length through a 

 bar of nickel steel that had almost no coeffi- 

 cient of expansion. It was proposed that 

 these two thermometers should be tried 

 together in a balloon sent up at night, so 

 that the disturbing effect of insolation 

 might be avoided. A statoscope, to indicate 

 the rise or fall of a manned balloon, the in- 

 vention of Captain Eoyas, was exhibited by 

 Major Vivez y Vieh, of Madrid, and a 

 project of directing an airship from the 

 ground by means of Hertzian waves was 

 explained by Mr. Alexander, of Bath, Eng- 

 land. 



Kites and kite-stations were then con- 

 sidered, the writer first presenting his plan 



to explore the atmosphere over the tropical 

 and equatorial oceans by means of kites 

 flown from a steamship, as outlined in 

 Science, Vol. XIV., pages 412-13 and 

 896-97. He stated that application had 

 been made to the Carnegie Institution for a 

 grant of $10,000 to defray a portion of the 

 expenses, but still he hoped his German 

 colleagues might cooperate in this large 

 undertaking. The project was enthusiastic- 

 ally received, Dr. von Bezold remarking 

 that the importance of the proposed investi- 

 gation consisted in the fact that quite a dif- 

 ferent vertical distribution of temperature 

 might be expected to prevail over the ocean 

 from that found over the land. The con- 

 ditions of equilibrium are disturbed over 

 the ocean, not by heating the lower layers of 

 air but by cooling the upper strata, and 

 hence at sea and on the coast thunder- 

 storms are most frequent during the cold 

 season and at night, while on land the re- 

 verse obtains. More than two years ago he 

 had proposed to explore these regions by 

 an expedition furnished with kites which 

 project was unavoidably postponed, but 

 now, as Mr. Berson stated it might be car- 

 ried out in cooperation with Mr.. Rotch. 

 Professor Koppen, of Hamburg, said that 

 the Scandinavian Hydrographic Congress 

 had arranged four cruises a year in the 

 northern seas and the Deutsche Seewarte 

 would operate meteorological kites on board 

 the vessel. The Gottingen Society of 

 Science has recently sent out a geophysical 

 expedition to Samoa, which was to fly kites 

 with registering instruments, both there 

 and on the return voyage. On the Lake of 

 Constance, also, meteorological kite ascents 

 will be made upon a vessel furnished by 

 Count Zeppelin, through the cooperation of 

 the Meteorological Service of Alsace-Lor- 

 raine. A resolution was then passed, recog- 

 nizing the importance of Mr. Rotch 's pro- 

 posed voyage to increase our Imowledge of 

 the distribution of temperature in the 



