Summit of the Peak of Teneriffe in February 1829. 1-41 



us, which lowered the thermometer to 44 0, 5 : we at the same 

 time passed a small extinct volcano called Montana Ncgra, 

 or more generally known by the name of Los Gorros ; in it 

 are several caves, which the men who supply Santa Cruz and 

 Orotava with snow, use as ice-houses, by filling them with 

 snow, which they collect at the foot of the Peak at certain 

 seasons of the year : when snow cannot be collected there, 

 they go up to a cave, which is 2131 feet higher up. For 

 four baskets of snow, which is a mule-load, they obtain at 

 Santa Cruz a sum only equal to 135. 4c?. after undertaking a 

 journey of nearly 80 miles, reckoning from their own house 

 and back again. These men likewise act as guides to those 



i . 



who visit the Peak, and are generally found both faithful and 

 obliging. 



At twelve o'clock we arrived at the foot of the Peak, and 

 halted for a few minutes. The surface was composed of red- 

 dish-coloured pumice, studded over with large blocks ofgriin- 

 steinic lava of a grayish-green colour, mixed with crystals of 

 felspar, masses of common obsidian, and large bushes of 

 mountain broom. We found the temperature of the air to 

 fluctuate considerably, according as the wind blew away the 

 surrounding vapour. When we first arrived, the thermo- 

 meter stood at 44° in the shade; but it shortly afterwards rose 

 to 50° in the same situation, and to 57° where it was indirectly 

 exposed to the influence of the sun. A small surface of aether, 

 •25 of a line in depth, and sheltered from the sun and wind, 

 evaporated in rather less than three minutes; and the bulb of 

 a thermometer, covered with silk and kept moist, lowered the 

 mercury three degrees in the same time. When I ascended 

 the Peak on the 13th of October 1827, the same experiments 

 had different results. A similar quantity of aether, and at the 

 same spot, evaporated in about one minute and a half; and 

 the thermometer, enveloped in the same manner, fell 4°*5 in 

 less than three minutes. I found the boiling point of water to 

 be from 189 o, 5tol90°, and strong Havanna rum boiled at 175°; 

 in the town of Orotava (1040 feet above the sea) water boiled at 

 from 209°'2.5 to 209 Ol 5. When I ascended the Peak on the 

 13th of October 1827, water boiled at the same spot at 188 0, 5. 



We began to mount the Peak by a very steep ascent over 

 beds of small yellowish-coloured pumice, between two em- 

 bankments or currents of lava, which had separated from the 

 general mass, called Mai Pais, situated at Alta Vista Arriba, 

 1664 feet above the foot of the mountain. These currents 

 are not in connected masses, but consist of immense blocks 

 of various sizes and forms ; and different parts of the same 

 current appear to have undergone various states of combus- 

 tion [?J : 



