CANARY ISLANDS. 71 



that the absolute height of the Peak of Teneriffe, above 

 the level of the ocean, is 1905'65 toises,* or 12,177 English 

 feet. 



From the action of the elements, and the numerous 

 lateral eruptions to which this mountain has been subject 

 these last two centuries, its elevation has been considerably 

 diminished. I am informed that the appearance of its 

 summit was sensibly altered after the deluge of 1826, and 

 to compare the present outline of its summit with the 

 ancient drawings of it, there is but a very faint resemblance. 



It has been asserted, that volcanoes always increase in 

 height, until they are extinguished, when they begin to 

 fall, and, by degrees, sink into the caverns below. This, 

 undoubtedly, has been the case in the present instance, 

 the lateral eruptions having exhausted a great quantity of 

 the bowels of the mountain, and the portions above, being 

 too heavy for their hollow foundations, have given way and 

 settled down into the mountain. Some are of an opinion, 

 however, that the crater of this volcano has never been 

 totally extinguished, and that another grand eruption is 

 approaching, from the fact that a hot vapor issues from its 

 nostrils, which is said to have gradually increased in tem- 

 perature within these last thirty years. This may be the 

 case, but it is a matter of uncertainty ; for the first time 

 that I visited this volcano, the vapor had a temperature of 

 more than 220°, and about two weeks afterwards, I found 

 that it had a temperature of only 160° ; but one of the 

 probable causes of this change was, that the summit of the 

 mountain existed under very different circumstances, at 

 one time a tremendous hurricane, and the other, scarcely 

 a breath of wind. 



For many evenings past, my attention has been particu- 

 larly arrested by an extraordinary brilliancy of the zodiacal 

 light, and the sudden departure of the twilight. The 

 former is a beautiful phenomenon, constantly existing at 

 the equator, and presents itself just before sunrise or after 



* My first basis was divided into toises of 6*39 English feet each, and of course, 

 all the distances calculated from it, were of the same proportion ; but more accu- 

 rately the Fronch toise contains 6*3957 feet ; hence the Peak has an elevation of 

 about 1904 toises. 



