M. Humboldt on two Attempts to ascend Chiviborazo. 309 



herent, project through the eternal snow." The loss of a na- 

 tural philosopher, like Boussingault, would have been inde- 

 scribably dearly-bought with the little gain which undertakings 

 of this sort can afford to science. 



Although, thirty years ago, I expressed the wish that the 

 height of Chimborazo might be again trigonometrically mea- 

 sured, there yet remains some uncertainty as to the abso- 

 lute result. Don Jorge Juan and the French Academicians, 

 after different combinations of the same elements, or at least 

 after operations, the whole of which were in common, give the 

 heights ot 3380 and 3217 toiscs ; heights which present a dif- 

 ference of 3yth. The result of my trigonometrical operation 

 (3350 T.) falls between them, but approaches to within tis^h o^ 

 the Spanish estimate. Bouguer's lesser result is founded, in part 

 at least, upon the height of the city of Quito, which he esti- 

 mated at 30 to 40 toises too low. He gives, according to old 

 barometric formula, without correction for the temperature, the 

 height of 1 462, instead of 1507 and 1492 toises, the very ac- 

 cordant I'esults, respectively, of Boussingault's observations and 

 my own. The height at which I estimate the plain of Tapia, 

 where I measured a base of 873 toises in length, * also appears 

 to be pretty free from error. I found the same to be 1482 

 toises ; and Boussingault, at a very different season of the year, 

 and thus with other diminutions of temperature im the atmo- 

 spheric strata, 1471 toises. Bouguer''s operation was, on the 

 other hand, very complicated, as he was obliged to estimate the 

 height of the valley-plain, between the eastern and western 

 Andes, by means of very small angles of height of the trachyte- 

 pyramid of Ilinissa, measured in the under region of the coast. 

 The only considerable mountain of the earth, of which the mea- 

 surements now agree within ^Igth, is Mont Blanc; for Monte 

 llosa was, with four different series of triangles by an excellent 

 observer, the astronomer Carlini, estimated at 2319, 2343, 

 2357, and 2374 toises ; by Oriani, likewise by triangulation, 

 at 2390 toises ; differences of ^'jth. The oldest detailed men- 

 lion of Chimborazo, I find to be that of the spirited, somewhat 



* Humboldt, Recueil d'observations astronoiniques, d'operations trigono- 

 metriques, etc. T. I. p. Ixxii. 



