264 PROCEEDINGS OF THE AMERICAN ACADEMY. 



and upon his yacht, the " Princesse- Alice," during the summer of 1904, 

 kite-flights were made in the region bounded by Spain, the Azores, and 

 the Canaries. Although a height exceeding that of the Peak of Tene- 

 riffe was attained several times, the southwest current, which had been 

 reported on this mountain, was not found. Thereupon Professor Her- 

 gersell stated that he believed this current was due to the disturbing 

 influence of the island, and that in the region explored the inter- 

 change of air takes place through the northwest current, which he had 

 observed.* 



These conclusions, which involved a fundamental principle of meteo- 

 rology, namely, the existence of the upper return-trades, seemed to 

 demand further investigation, and accordingly M. Teisserenc de Bort 

 and the writer undertook to execute this through their assistants, 

 Messrs. Maurice of Trappes Observatory and Clayton of Blue Hill 

 Observatory. Mr. Clayton made the voyage from Boston to Gibraltar, 

 via the Azores, in June, 1905, on the White Star steamer " Romanic," 

 and flew kites six times to an average height of about 1000 meters. 

 The steam-yacht "Otaria," of 350 tons, purchased and equipped by 

 M. Teisserenc de Bort for exploring the atmosphere, and having on 

 board Messrs. Maurice and Clayton as the scientific staff, went during 

 the months of July and August, 1905, at the mutual expense of her 

 owner and the writer, from the Mediterranean, via Madeira, the 

 Canary and Cape Verde islands, to latitude 10° north, longitude 30° 

 west, returning via the Azores and Corunna (Spain) to Havre. Seven- 

 teen kite-flights were made over the ocean besides two in the harbor 

 of Santa Cruz (Teneriff'e) to study the sea-breeze, and another off 

 Corunna (Spain) during the total solar eclipse of August 30, 1905. 

 In this way continuous records of barometric pressure, air-temperature, 

 relative humidity, and wind-velocity were obtained from sea-level up to 

 the extreme height of 2200 meters, although wind-velocity was re- 

 corded to an altitude of 3100 meters. The direction of the wind 

 was obtained by measuring the azimuth of the kites. Direct observa- 

 tions were made by Mr. Clayton upon the Peak of Teyde (Teneriffe) 

 to a height of 3700 meters, and upon the Peak of Fogo (Cape Verdes) 

 to 2200 meters, and observations of clouds enabled the wind to be 

 ascertained about 500 meters higher. To attain a greater height in 

 the free air than w^as possible with kites, the " Otaria " was provided 

 with large paper balloons, eleven of which, filled with hydrogen gas, 

 were liberated from the islands of St. Michaels (Azores), Madeira, 



* Conference de la Commission Internationale pour 1' Aerostation Scicntifique, 

 St. Tctersbour}?, 1901, Supplement 7. 



