3 



Mr. Oltmanns and me in 1811, in my Collection of Astrono- 

 mical Observations, Vol. 1. p. 20. A more profound exa- 

 mination of the declination of the southern stars, and of the 

 rate of the chronometer, necessarily modified the latitudes 

 and longitudes a little ; so that on the map engraved in 1816, 

 by Mr. Michaelis, the longitudes of Pinto and the Island of 

 Bruxas are 0° 47' and 1° 34'. The profile of the land be- 

 tween Honda and the tableland of Bogota is founded on the 

 barometric observations, which I have published in my 

 Nivellement des Andes, No. 64-130. 



ALEXANDRE DE HUMBOLDT. 



Paris, March, 1821. 



W. Pople, Printer, 

 (57, Chancery Lane. 



