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.
During the total eclipse the lunar disc displayed, as almost always happens, a reddish tint, without disappearing; the edges, examined with a sextant, were strongly undulating, notwithstanding the considerable altitude of the orb. It appeared to me that the moon was more luminous than I had ever seen it in the temperate zone. The vividness of the light, it may be conceived, does not depend solely on the state of the atmosphere, which reflects, more or less feebly, the solar rays, by inflecting them in the cone of the shade. The light is also modified by the variable transparency of that part of the atmosphere across which we perceived the moon eclipsed. Within the tropics great serenity of the sky and a perfect dissolution of the vapours diminish the extinction of the light sent back to us by the lunar disc. I was singularly struck during the eclipse by the want of uniformity in the distribution of the refracted light by the terrestrial atmosphere. In the central region of the disc there was a shadow like a round cloud, the movement 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 appointed to take the survey of the coast under the direction of M. Fidalgo, 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 of 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 Bello and that of the isthmus by the Rio 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 along the Cordilleras by Santa Fe de Bogota, Popayan, Quito and Caxamarca would be preferable to the sea-voyage, and would furnish an immense field for exploration. The predilection of Europeans for the tierras frias, that is to say, the cold and temperate climate that prevails on the back of the Andes, gave further weight to these counsels. The distances were known, but we were deceived with respect to the time it would take to traverse them on mules' backs. We did not imagine that it would require more than eighteen months to go from Carthagena to Lima. Notwithstanding this delay, or rather owing to the slowness with which we passed through Cundinamarca, the provinces of Popayan and Quito, I did not regret having sacrificed the passage of the isthmus to the route of Bogota, for every step of the journey was full of interest both geographically and botanically. This change of direction gave me occasion to trace the map of the Rio Magdalena, to determine astronomically the position of eighty points situated in the inland country between Carthagena, Popayan, and the upper course of the river Amazon and Lima, to discover the error in the longitude of Quito, to collect several thousand new plants, and to observe on a vast scale the relations between the rocks of syenitic porphyry and trachyte with the fire of volcanoes.
The result of those labours of which it is not for me to appreciate the importance have long since been published. My map of the Rio Magdalena, multiplied by the copies of the year 1802 in America and Spain, and comprehending the country between Almaguer and Santa Marta, from 1 degree 54 minutes to 11 degrees 15 minutes latitude, appeared in 1816. Till that period no traveller had undertaken to describe New Grenada; and the public, except in Spain, knew the navigation of the Magdalena only by some lines traced by Bouguer. That learned traveller had descended the river from Honda; but, being in want of astronomical instruments, he had ascertained but four or five latitudes, by means of small dials hastily constructed. The narratives of travels in America are now singularly multiplied. Political events have led numbers of persons to those countries: and travellers have perhaps too hastily published their journals on returning to Europe. They have described the towns where they resided, and landscape scenery remarkable for beauty; they have furnished information respecting the inhabitants and the different modes of travelling in barks, on mules or on men's backs. These works, several of which are agreeable and instructive, have familiarized the nations of the Old World with those of Spanish America, from Buenos Ayres and Chili as far as Zacatecas and New Mexico. But unfortunately, in many instances, the want of a thorough knowledge of the Spanish language and the little care taken to acquire the names of places, rivers and tribes, have occasioned extraordinary mistakes.
During the six days of our stay at Carthagena our most interesting excursions were to the Boca Grande and the hill of Popa; the latter commands the town and a very extensive view. The port, or rather the bahia, is nearly nine miles and a half long, if we compute the length from the town (near the suburb of Jehemani or Xezemani) to the Cienega of Cacao. The Cienega is one of the nooks of the isle of Baru, south-west of the Estero de Pasacaballos, by which we reach the opening of the Dique de Mahates. Two extremities of the small island of Tierra Bomba form, on the north, with a neck of land of the continent, and on the south, with a cape of the island of Baru, the only entrances to the Bay of Carthagena; the former is called Boca Grande, the second Boca Chica. This extraordinary conformation of the land has given birth, for the space of a century, to theories entirely contradictory respecting the defence of a place which, next to the Havannah and Porto Cabello, is the most important of the main land and the West Indies. Engineers differed respecting the choice of the opening which should be closed; and it was not, as some writers have stated, after the landing of Admiral Vernon, in 1741, that the idea was first conceived* of filling up the Boca Grande. (* Don Jorge Juan in his Secret Notices addressed to the Marques de la Ensenada says: La entrada antigua era por un angosto canal que llaman Boca Chica; de resultas de esta invasion se acordo deja cioga y impassable la Boca Grande, y volver a abrir la antigua fortificandola. [The old entrance was by a narrow channel called the Boca Chica; but after this invasion it was determined to close up the Boca Grande and to open the old passage, fortifying it.] Secr. Not. volume 1 page 4.) The English forced the small entrance when they made themselves masters of the bay; but being unable to take the town of Carthagena, which made a gallant resistance, they destroyed the Castillo Grande (called also Santa Cruz) and the two forts of San Luis and San Jose which defended the Boca Chica.
The apprehension excited by the proximity of the Boca Grande to the town determined the court of Madrid, after the English expedition, to shut up the entrance along a distance of 2640 varas. From two and a half to three fathoms of water were found; and a wall, or rather a dyke, in stone, from fifteen to twenty feet high, was raised on piles. The slope on the side of the water is unequal, and seldom 45 degrees. This immense work was completed under the Viceroy Espeleta in 1795. But art could not vanquish nature; the sea is unceasingly though gradually silting up the Boca Chica, while it labours unceasingly to open and enlarge the Boca Grande. The currents which, during a great part of the year, especially when the bendavales blow with violence, ascend from south-west to north-east, throw sand into the Boca Chica, and even into the bay itself. The passage, which is from seventeen to eighteen fathoms deep, becomes more and more narrow,* and if a regular cleansing be not established by dredging machines, vessels will not be able to enter without risk. (* At the foot of the two forts San Jose and San Fernando, constructed for the defence of the Boca Chica, it may be seen how much the land has gained upon the sea. Necks of land are formed on both sides, and also before the Castillo del Angel which, northward, commands the fort of San Fernando.) It is this small entrance which should have been closed; its opening is only 250 toises, and the passage or navigable channel is 110 toises. If it should one day be determined to abandon the Boca Chica, and re-establish the Boca Grande in the state which nature seems to prescribe, new fortifications must be constructed on the south-south-west of the town. This fortress has always required great pecuniary outlays to keep it up.
The insalubrity of Carthagena varies with the state of the great marshes that surround the town on the east and north. The Cienega de Tesca is more than fifteen miles long; it communicates with the ocean where it approaches the village of Guayeper. When, in years of drought, the heaped-up earth prevents the salt water from covering the whole plain, the emanations that rise during the heat of the day when the thermometer stands between 28 and 32 degrees are very pernicious to the health of the inhabitants. A small portion of hilly land separates the town of Carthagena and the islet of Manga from the Cienega de Tesca. Those hills, some of which are more than 500 feet high, command the town. The Castillo de San Lazaro is seen from afar rising like a great rocky pyramid; when examined nearer its fortifications are not very formidable. Layers of clay and sand, belonging to the tertiary formation of nagelfluhe, are covered with bricks and furnish a kind of construction which has little stability. The Cerro de Santa Maria de la Popa, crowned by a convent and some batteries, rises above the fort of San Lazaro and is worthy of more solid and extensive works. The image of the Virgin, preserved in the church of the convent, has been long revered by mariners. The hill itself forms a prolonged ridge from west to east. The calcareous rock, with cardites, meandrites and petrified corals, somewhat resembles the tertiary limestone of the peninsula of Araya near Cumana. It is split and decomposed in the steep parts of the rock, and the preservation of the convent on so unsolid a foundation is considered by the people as one of the miracles of the patron of the place. Near the Cerro de la Popa there appears, on several points, breccia with a limestone cement containing angular fragments of Lydian stone. Whether this formation of nagelfluhe is superposed on tertiary limestone of coral, and whether the fragments of the Lydian stone come from secondary limestone analogous to that of Zacatecas and the Moro de Nueva Barcelona, are questions which I have not had leisure to investigate. The view from the Popa is extensive and varied, and the windings and rents of the coast give it a peculiar character. I was assured that sometimes from the windows of the convent and even in the open sea, before the fort of Boca Chica, the snowy tops of the Sierra Nevada de Santa Marta are discernible. The distance of the Horqueta to the Popa is seventy-eight nautical miles. This group of colossal mountains is most frequently wrapped in thick clouds: and it is most veiled at the season when the gales blow with violence. Although only forty-five miles distant from the coast, it is of little service as a signal to mariners who seek the port of Saint Marta. Hidalgo during the whole time of his operations near the shore could take only one observation of the Nevados.
A gloomy vegetation of cactus, Jatropha gossypifolia, croton and mimosa covers the barren declivity of Cerro de la Popa. In herbalizing in those wild spots, our guides showed us a thick bush of Acacia cornigera, which had become celebrated by a deplorable event. Of all the species of mimosa the acacia is that which is armed with the sharpest thorns; they are sometimes two inches long; and being hollow, serve for the habitation of ants of an extraordinary size. A woman, annoyed by the jealousy and well founded reproaches of her husband, conceived a project of the most barbarous vengeance. With the assistance of her lover she bound her husband with cords, and threw him, at night, into a bush of Mimosa cornigera. The more violently he struggled, the more the sharp woody thorns of the tree tore his skin. His cries were heard by persons who were passing, and he was found after several hours of suffering, covered with blood, and dreadfully stung by the ants. This crime is perhaps without example in the history of human turpitude: it indicates a violence of passion less assignable to the climate than to the barbarism of manners prevailing among the lower class of the people.
My most important occupation at Carthagena was the comparison of my observations with the astronomical positions fixed by the officers of the expedition of Fidalgo. In the year 1783 (under the ministry of M. Valdes) Don Josef Espinosa, Don Dionisio Galiano and Don Josef de Lanz proposed to the Spanish government a plan for taking a survey of the coast of America, in order to extend the atlas of Tofino to the western colonies. The plan was approved; but it was not till 1792 that an expedition was fitted out at Cadiz, and they were enabled to commence their scientific operations at the island of Trinidad.