DIFFERENCE OF TEMPERATURE. 171 



By the annexed table it may plainly be seen, 

 that there is a great difference of temperature 

 between the eastern and western sides of the Cor- 

 dillera of the Andes, although there is always 

 much more snow on the western or Chili side, 

 than on the eastern or Mendoza side. I can 

 only account for this difference by the preva- 

 lence of the SW. wind, which is received on 

 the Chili side before passing over the snow; 

 whereas on the Mendoza side, having to pass 

 over an immense track of snow, it always blows 

 down the mountains piercingly keen; look, for 

 instance, at the difference of temperature be- 

 tween the 20^^ and 23r(/, when we were about 

 equal distances from the Cumbre on the differ- 

 ent sides. I do not take the 21st as a criterion, 

 because on that day it blew a dreadful storm. 

 See also the difference between sunrise and sun- 

 set, at Mendoza and Valparaiso. 



