The effect of altitude 



245 



higher altitudes at which the working life of man is carried out on 

 a normal scale. As a station for the study of climate the Canadas 

 offer, among other advantages, a relative immunity from wind. This 

 in view of the investigations published by Lyth (1) is a factor worthy of 

 consideration. The island of Teneriffe consists roughly of a huge 

 crater about 8000 9000 feet in height. The diameter from lip to 



FIG. 116. The Canadas showing the living house and the laboratory. Espigone, one 

 of the summits, on the lip of the " old crater" in the background. (Douglas.) 



lip is eight miles. On the south side of the island the lip is incom- 

 plete. The inside of the tip is a steep, not quite precipitous, cliff, 

 down which you must climb for a thousand or two feet, unless you 

 enter the crater as we did by a gap in the cliffs we called the Portillio. 

 We were then inside the old crater ; our back was to the cliff", which 

 in places rises in named summits, Guajara and Espigone for instance. 

 Our faces were towards a level plateau of sand. 



