RESULTS OF THE FRANCO-AMETIICAN EXPEDITION TO 

 EXPLORE THE ATMOSPHERE IN THE TROPICS. 



By a. Lawrence Rotch. 



Presented February 14, 190G. Received September 13, 190G. 



It has long been believed that the ascending currents above the ther- 

 mal ei^uator proceed immediately over the northeast and southeast 

 trade- winds as southwest and northwest anti-trades. It is possible that 

 part of the anti-trade sinks down over the high barometric pressure in 

 the North and South Atlantic oceans and returns with the trade-winds, 

 but the greater portion descends north and south of the origin of the 

 trades and continues to the poles as the prevailing southwest or north- 

 west winds of the North and South Temperate zones, respectively. 

 The facts upon which this theory is based, as regards the Atlantic 

 Ocean, are mainly observations upon the Peak of Teneriffe, where the 

 southwest wind can be observed the whole year; and although it 

 is lower in winter than in summer, there are no observations which 

 prove that this anti-trade ever reaches the surface of the ocean. 



The author, after he had made the first meteorological observations 

 over the ocean, with kites flown from a transatlantic steamer in 1901, 

 concluded that a vessel, which could be navigated at will, would enable 

 meteorological data to be obtained with kites independently of the 

 natural wind.^ He suggested the application of this method to 

 the exploration of the atmosphere in the trade-wind region at the 

 Glasgow meeting of the British Association in 1901, ^ and at the 

 Berlin Congress for Scientific Aeronautics in 1902.^ In order to or- 

 ganize such an expedition, applications for aid were addressed in 1902 

 to the Prince of Monaco, and in 1903 to the Carnegie Institution, but 

 without receiving the desired assistance. However, Professor Herge- 

 sell, President of the International Commission for Scientific Aero- 

 nautics, succeeded in interesting the Prince of Monaco in the scheme, 



1 Science, 14, 412 and 800. 



* Report Brit. Ass. Adv. Sci., Glasgow, 1901, Transactions Section E. 

 ' Protokoll dcr S. Versamnihing der Internationaleu Komuiission fUr wissen- 

 schaftliche Luftschiffahrt, Beilage 11. 



