222 ENTRANCE OF THE PORT 



the disc there was a shadow, like a round cloud, the move- 

 ment of which was from east to west. The part where the 

 immersion was to take place was consequently, a few minutes 

 prior to the immersion, much more brightly illumined than 

 the western edges. Is this phenomenon to be attributed to 

 an inequality of our atmosphere; to a partial accumulation 

 of vapour, which, by absorbing a considerable part of the 

 solar light, inflects less on one side the cone of the shadow 

 of the earth ? If a similar cause, in the perigee of central 

 eclipses, sometimes renders the disc invisible, may it not 

 happen also that only a small portion of the moon is seen; 

 a disc, irregularly formed, and of which different parts 

 were successively enlightened? 



On the morning of the 30th of March we doubled Punta 

 Gigantes, and made for the Boca Chica, the present 

 entrance of the port of Carthagena. From thence the 

 distance is seven or eight miles to the anchorage near the 

 town; and although we took a practico to pilot us, we 

 repeatedly touched on the sandbanks. On landing, I 

 learned, with great satisfaction, that the expedition ap- 

 pointed to take the survey of the coast, under the direction 

 of M. Eidalgo, had not yet put to sea. This circumstance 

 not only enabled me to ascertain the astronomical position 

 of several towns on the shore, which had served me as 

 points of departure in fixing chronometrically the longitude 

 af the Llanos and the Orinoco, but also served to guide me 

 with respect to the future direction of my journey to Peru. 

 The passage from Carthagena to Porto 6ello, and that of 

 the isthmus by the Bio Chagres and Cruces, are alike short 

 and easy; but it was to be feared, that we might stay long 

 at Panama before we found an opportunity of proceeding to 

 Guayaquil, and in that case the voyage on the Pacific would 

 be extremely lingering, as we should have to sail against 

 contrary winds and currents. I relinquished with regret 

 the hope of levelling by the barometer, the mountains of 

 the isthmus, though it would then have been difficult to 

 foresee that at the present time (1827), while measurements 

 have been effected on so many other points of Mexico and 

 Columbia, we should remain in ignorance of the height of 

 the ridge which divides the waters in the isthmus. The 

 persons we consulted all agreed that the journey by land 



