257 



Now, the problem of the breadth of the isthmus 

 does not solely depend on the determination of 

 the latitude. The government of Columbia hav- 



I announced fifteen years ago, on the relative position of the 

 most important points of the southern and northern coasts of 

 the isthmus. Panama was anciently believed (Don Jorge 

 Juan. Travels in South America, Vol. i, p. 99), to be 31< 

 to the west of Portobello. La Cruz (1775), and Lopez 

 (1785) have followed this supposition, founded only on a 

 plan of the direction of the route, taken with a compass. 

 But in 1802, Lopez (Mapa del Reyno de Tierra Firme y sus 

 provincias de Veragua y Darien) began to place Panama 17' 

 to the east of Portobello. In the map of the Deposito of 

 1805, this difference of meridians was reduced to 7 7 j finally, 

 the map of the Deposito of 1817 places Panama 25' east of 

 Portobello. The following are other differences of latitude on 

 which the breadth of the isthmus depends : — 



Map of 1809. Map of 1817. 



Southern coast between the mouths 

 of the Rio Juan Diaz and the Rio 

 Jucumeonthe east of Panama,in 



the meridian of Punta San Bias 8° 54' 9° 2|' 

 Northern coast forming the bot- 

 tom of the gulf Mandinga, or 

 of San Bias, on the south of the 



Islas Mulatas 9° 9 ; 9° 27^' 



From this difference of latitudes 



the results are, for the minimum 



of the breadth of the isthmus, 



nearly 14,250 toises, according 



to the map of 1805, and nearly 



24,463 toises, according to the 



map of 1817. 

 Punta San Bias, N.W. part of the 



gulf of Mandinga 9° 33' 9° 34J' 



VOL. VI. S 



