The effect of altitude 



247 



beautiful than in the Alps. To get to the Portillio you must ride 

 through woods of heath which rises seven or eight feet in the air 

 and bursts into blossom above your head. But this has all been 

 left behind. The moisture condenses into clouds, which hang over 

 the island in a sheet at an altitude of 4000 5000 feet ; through these 

 clouds you penetrate. Once you arrive within the old crater you 

 have reached a new climate. Between you and the clouds there is 

 an impassable rampart. No vestige of mist was seen either above 

 us or around us during our sojourn in Las Canadas, the occasional 

 appearance of a cloud top above the lip of the crater was the only 

 reminder that such a thing as a cloud existed. 



FIG. 118. Transport of apparatus to the Alta Vista. (Douglas.) 



With the absence of moisture there was a corresponding absence 

 of vegetation scarcely anything green was to be seen. There is a 

 broom, called retama, that grows in considerable quantities, there 

 is a viola which seems to survive, but, beyond these, I noticed no 

 plant. Everything was arid. Imagine a mountain of coke from the 

 gas-works rising 5000 feet above you and you have pictured to your- 

 self the peak of Teneriffe as seen from the Canadas. 



In some places, the " coke " is replaced by pummice, in others the 



