44 
INTERNAL TEMPERATURES OF 
an effect in maintaining a low rate of absorption of heat-rays as well as in 
preventing evaporation. The wood of a thick trunk is mostly of secondary 
origin. It contains a large percentage of water and comparatively small 
intercellular air-spaces 1 . 
Photograph 3. Aloe dichotoma (Aloe B), Wasserfall, Great Karasberg. 
December, 1912. 
2. Methods. 
The work was done during the course of an expedition undertaken for 
other purposes. Only ten days (Dec. 12-21, 1912) could be devoted to it, and 
this only because the principal work of the expedition was, for the time being, 
hindered by lack of rain. The methods employed were necessarily rough. 
With more suitable instruments and more time to devote to this purpose, the 
observations now recorded could be usefully carried further in more than one 
direction. 
1 Worsdell, l.c. 
