There was to be an eclipse of the moon during the night, and the next day an occultation of alpha Virginis. The observation of the latter phenomenon might have been very important in determining the longitude of Carthagena. In vain I urged the captain to allow one of his sailors to accompany me by land to the foot of Boca Chica, a distance of five miles. He objected on account of the wild state of the country in which there is neither habitation nor path. A little incident which might have rendered Palm-Sunday more fatal justified the prudence of the captain. We went by moonlight to collect plants on the shore; as we approached the land, we saw a young negro issue from the thicket. He was quite naked, loaded with chains, and armed with a machete. He invited us to land on a part of the beach covered with large mangroves, as being a spot where the surf did not break, and offered to conduct us to the interior of the island of Baru if we would promise to give him some clothes. His cunning and wild appearance, the often-repeated question whether we were Spaniards, and certain unintelligible words which he addressed to some of his companions who were concealed amidst the trees, inspired us with some mistrust. These blacks were no doubt maroon negroes: slaves escaped from prison. This unfortunate class are much to be feared: they have the courage of despair, and a desire of vengeance excited by the severity of the whites. We were without arms; the negroes appeared to be more numerous than we were and, thinking that possibly they invited us to land with the desire of taking possession of our canoe, we thought it most prudent to return on board. The aspect of a naked man wandering on an uninhabited beach, unable to free himself from the chains fastened round his neck and the upper part of his arm, was an object calculated to excite the most painful impressions. Our sailors wished to return to the shore for the purpose of seizing the fugitives, to sell them secretly at Carthagena. In countries where slavery exists the mind is familiarized with suffering and that instinct of pity which characterizes and enobles our nature is blunted. Whilst we lay at anchor near the island of Baru in the meridian of Punta Gigantes I observed the eclipse of the moon of the 29th of March, 1801. The total immersion took place at 11 hours 30 minutes 12.6 seconds mean time. Some groups of vapours, scattered over the azure vault of the sky, rendered the observation of the immersion uncertain.