256 



ledge of the heights of the isthmus of Panama, 

 the last labours of M. Fidalgo, and other 

 Spanish navigators, have at least furnished more 

 precise statements on its configuration, and the 

 minimum of its breadth. This minimum is not 

 15 miles, as the first maps of the Deposito hy- 

 drogrqfico indicate, but 25? miles (60 to a de- 

 gree), that is, 8| marine leagues, or 24,500 

 toises ; for the dimensions of the gulf of San 

 Bias, called also Ensenada de Mandinga, on 

 account of the small river of that name which 

 flows into it, have given rise to great errors. 

 This gulf penetrates into the land 17 miles less 

 than was supposed in 1805, in taking the plan 

 of the archipelago of the Islas Mulatas*. What- 

 ever credit the last astronomical observations 

 appear to merit, and on which the map of the 

 isthmus is founded, published by the Royal 

 Deposit of the Marine of Madrid in 1817, we 

 must not forget that these operations compre- 

 hend only the northern coast, which appears 

 never yet to have been connected either by a 

 chain of triangles, or chronometrically (by the 

 transport of time), with the southern coast. 



* See my Political Essay, Vol. iv, p. 348. In comparing 

 the two maps Deposito hydrogrqfico de Madrid, bearing the 

 title Carta eserica del Mar de Antillas y de las Costas de Tierra 

 Firme desde la isla de la Trinidad hast a el golfo de Honduras, 

 1806, and the Quarto Hoja que comprehende la provincia de 

 Cartagena, 1819, we see how well founded were the doubts 



