151 



t( The ground in the neighbourhood of the port of Oro- 

 tava being unequal, and intersected with vales, it was not 

 possible for us to find a base extensive enough to determine 

 the distance of the Peak by a single triangle, and we em- 

 ployed three. We measured near La Paz, a country house 

 of Mr. Cologan, our first basis *, a 6, of 229 '5 toises j by 

 means of this we calculated a second, a c, of 614 toises j 

 and afterward a third, c d, of 1526 toises. The point c was 

 the summit of the hill, called by the natives the Montanne 

 del Puerto, which commands the town of Orotava. The sta- 

 tion d is the western extremity of a gallery of the house of Co- 

 lonel Franqui, at the villa del Orotava, near the dragon-tree 

 so celebrated for it's size and age. It appears that the base 

 of P. Feuillee had been measured on a plain sufficiently large, 

 but not horizontal, at the foot of the hill of La Paz, near 

 Mr. Cologan's country house. Our base a b was measured 

 successively by two different parties : the first found it 1377 

 feet 6 inches, the second 1377 feet, 3 inches, 6 lines. Both 

 made use of three rods of fifteen feet each, carefully measured 

 by a three foot rule, which Mr. Varela had compared at 

 Cadiz with the Peruvian toise of Mr. Goden. The following 

 were the angles taken with a quadrant of a foot radius, made 

 by Ramsden, 



Triangle abc 

 b a c = 85° 53' 55" 

 a b c = 73 8 55 

 b c a = 20 57 15 



180 0 5 



Triangle a c d. 

 dac = 85° 58' 40'/ 

 d c a = 70 20 55 

 adc— 23 40 8 



179 59 43 



Triangle c P d. 

 e dP = 94° 0'40" 

 d c P = 76 34 0 



" We measured the three angles of the triangles abc and 

 a c d. As in the triangle c P d this kind of verification could 



* See Plate 1. 



