\ 



661 



The barometrical survey, of which I gave the 

 results in my Collection of Astronomical Obser- 

 vations (Vol. i, p. 295 — 298), has been recent- 

 ly rectified and extended by two travellers well 

 versed in every branch of the physical sciences, 

 MM. Boussingault and Rivero. Wherever my 

 early results differed from theirs, I have given 

 the preference to the latter. M. Boussingault 

 has transmitted the detail of his measurements 

 to the Institute of France. It must not be for- 

 gotten, that in my profil of the road from La 

 Guayra to Caraccas (PI. iv.) published in 1817, 

 the heights of Torrequemada, Curucuti, and 

 Puente del Salto, are simply founded on ap- 

 proximative estimates, and not on real mea- 

 sures. (Per. Nar., Vol. iii, p. 409.) At Salto, 

 la Venta, and Cumbre, M. Boussingault's re- 

 sults and mine differ but little ; in the measure- 

 ment of la Silla, which is the loftiest mountain 

 of those countries, the agreement (accidentally 

 no doubt), is within one toise ; but in the town 

 of Caraccas my heights appears less faulty. 

 I believed the custom-house to be 491 toises; 

 the barracks, 462 t. ; the Trinity, 454 t. ; the 

 great square, 446. According to MM. Bous- 

 singault and Rivero, who are furnished with 

 excellent barometers of Fortin, the middle of 

 the street of Carabobo is 477 toises above the 

 level of the sea. We did not measure at the same 

 parts of the town, and modern travellers give 



