We spent two days and a half in the little village of Maypures, on the banks of the great Upper Cataract, and on the 21st April we embarked in the canoe we had obtained from the missionary of Carichana. It was much damaged by the shoals it had struck against, and the carelessness of the Indians; but still greater dangers awaited it. It was to be dragged over land, across an isthmus of thirty-six thousand feet; from the Rio Tuamini to the Rio Negro, to go up by the Cassiquiare to the Orinoco, and to repass the two raudales.
When the traveller has passed the Great Cataracts, he feels as if he were in a new world, and had overstepped the barriers which nature seems to have raised between the civilized countries of the coast and the savage and unknown interior. Towards the east, in the bluish distance, we saw for the last time the high chain of the Cunavami mountains. Its long, horizontal ridge reminded us of the Mesa of the Brigantine, near Cumana; but it terminates by a truncated summit. The Peak of Calitamini (the name given to this summit) glows at sunset as with a reddish fire. This appearance is every day the same. No one ever approached this mountain, the height of which does not exceed six hundred toises. I believe this splendour, commonly reddish but sometimes silvery, to be a reflection produced by large plates of talc, or by gneiss passing into mica-slate. The whole of this country contains granitic rocks, on which here and there, in little plains, an argillaceous grit-stone immediately reposes, containing fragments of quartz and of brown iron-ore.
In going to the embarcadero, we caught on the trunk of a hevea* (* One of those trees whose milk yields caoutchouc.) a new species of tree-frog, remarkable for its beautiful colours; it had a yellow belly, the back and head of a fine velvety purple, and a very narrow stripe of white from the point of the nose to the hinder extremities. This frog was two inches long, and allied to the Rana tinctoria, the blood of which, it is asserted, introduced into the skin of a parrot, in places where the feathers have been plucked out, occasions the growth of frizzled feathers of a yellow or red colour. The Indians showed us on the way, what is no doubt very curious in that country, traces of cartwheels in the rock. They spoke, as of an unknown animal, of those beasts with large horns, which, at the time of the expedition to the boundaries, drew the boats through the valley of Keri, from the Rio Toparo to the Rio Cameji, to avoid the cataracts, and save the trouble of unloading the merchandize. I believe these poor inhabitants of Maypures would now be as much astonished at the sight of an ox of the Spanish breed, as the Romans were at the sight of the Lucanian oxen, as they called the elephants of the army of Pyrrhus.
We embarked at Puerto de Arriba, and passed the Raudal de Cameji with some difficulty. This passage is reputed to be dangerous when the water is very high; but we found the surface of the river beyond the raudal as smooth as glass. We passed the night in a rocky island called Piedra Raton, which is three-quarters of a league long, and displays that singular aspect of rising vegetation, those clusters of shrubs, scattered over a bare and rocky soil, of which we have often spoken.
On the 22nd of April we departed an hour and a half before sunrise. The morning was humid but delicious; not a breath of wind was felt; for south of Atures and Maypures a perpetual calm prevails. On the banks of the Rio Negro and the Cassiquiare, at the foot of Cerro Duida, and at the mission of Santa Barbara, we never heard that rustling of the leaves which has such a peculiar charm in very hot climates. The windings of rivers, the shelter of mountains, the thickness of the forests, and the almost continual rains, at one or two degrees of latitude north of the equator, contribute no doubt to this phenomenon, which is peculiar to the missions of the Orinoco.
In that part of the valley of the Amazon which is south of the equator, but at the same distance from it, as the places just mentioned, a strong wind always rises two hours after mid-day. This wind blows constantly against the stream, and is felt only in the bed of the river. Below San Borja it is an easterly wind; at Tomependa I found it between north and north-north-east; it is still the same breeze, the wind of the rotation of the globe, but modified by slight local circumstances. By favour of this general breeze you may go up the Amazon under sail, from Grand Para as far as Tefe, a distance of seven hundred and fifty leagues. In the province of Jaen de Bracamoros, at the foot of the western declivity of the Cordilleras, this Atlantic breeze rises sometimes to a tempest.
It is highly probable that the great salubrity of the Amazon is owing to this constant breeze. In the stagnant air of the Upper Orinoco the chemical affinities act more powerfully, and more deleterious miasmata are formed. The insalubrity of the climate would be the same on the woody banks of the Amazon, if that river, running like the Niger from west to east, did not follow in its immense length the same direction, which is that of the trade-winds. The valley of the Amazon is closed only at its western extremity, where it approaches the Cordilleras of the Andes. Towards the east, where the sea-breeze strikes the New Continent, the shore is raised but a few feet above the level of the Atlantic. The Upper Orinoco first runs from east to west, and then from north to south. Where its course is nearly parallel to that of the Amazon, a very hilly country (the group of the mountains of Parima and of Dutch and French Guiana) separates it from the Atlantic, and prevents the wind of rotation from reaching Esmeralda. This wind begins to be powerfully felt only from the confluence of the Apure, where the Lower Orinoco runs from west to east in a vast plain open towards the Atlantic, and therefore the climate of this part of the river is less noxious than that of the Upper Orinoco.
In order to add a third point of comparison, I may mention the valley of the Rio Magdalena, which, like the Amazon, has one direction only, but unfortunately, instead of being that of the breeze, it is from south to north. Situated in the region of the trade-winds, the Rio Magdalena has the stagnant air of the Upper Orinoco. From the canal of Mahates as far as Honda, particularly south of the town of Mompox, we never felt the wind blow but at the approach of the evening storms. When, on the contrary, you proceed up the river beyond Honda, you find the atmosphere often agitated. The strong winds that are ingulfed in the valley of Neiva are noted for their excessive heat. We may be at first surprised to perceive that the calm ceases as we approach the lofty mountains in the upper course of the river, but this astonishment ends when we recollect that the dry and burning winds of the Llanos de Neiva are the effect of descending currents. The columns of cold air rush from the top of the Nevados of Quindiu and of Guanacas into the valley, driving before them the lower strata of the atmosphere. Everywhere the unequal heating of the soil, and the proximity of mountains covered with perpetual snow, cause partial currents within the tropics, as well as in the temperate zone. The violent winds of Neiva are not the effect of a repercussion of the trade-winds; they rise where those winds cannot penetrate; and if the mountains of the Upper Orinoco, the tops of which are generally crowned with trees, were more elevated, they would produce the same impetuous movements in the atmosphere as we observe in the Cordilleras of Peru, of Abyssinia, and of Thibet. The intimate connection that exists between the direction of rivers, the height and disposition of the adjacent mountains, the movements of the atmosphere, and the salubrity of the climate, are subjects well worthy of attention. The study of the surface and the inequalities of the soil would indeed be irksome and useless were it not connected with more general considerations.
At the distance of six miles from the island of Piedra Raton we passed, first, on the east, the mouth of the Rio Sipapo, called Tipapu by the Indians; and then, on the west, the mouth of the Rio Vichada. Near the latter are some rocks covered by the water, that form a small cascade or raudalito. The Rio Sipapo, which Father Gili went up in 1757, and which he says is twice as broad as the Tiber, comes from a considerable chain of mountains, which in its southern part bears the name of the river, and joins the group of Calitamini and of Cunavami. Next to the Peak of Duida, which rises above the mission of Esmeralda, the Cerros of Sipapo appeared to me the most lofty of the whole Cordillera of Parima. They form an immense wall of rocks, shooting up abruptly from the plain, its craggy ridge of running from south-south-east to north-north-west. I believe these crags, these indentations, which equally occur in the sandstone of Montserrat in Catalonia,* (* From them the name of Montserrat is derived, Monte Serrato signifying a mountain ridged or jagged like a saw.) are owing to blocks of granite heaped together. The Cerros de Sipapo wear a different aspect every hour of the day. At sunrise the thick vegetation with which these mountains are clothed is tinged with that dark green inclining to brown, which is peculiar to a region where trees with coriaceous leaves prevail. Broad and strong shadows are projected on the neighbouring plain, and form a contrast with the vivid light diffused over the ground, in the air, and on the surface of the waters. But towards noon, when the sun reaches its zenith, these strong shadows gradually disappear, and the whole group is veiled by an aerial vapour of a much deeper azure than that of the lower regions of the celestial vault. These vapours, circulating around the rocky ridge, soften its outline, temper the effects of the light, and give the landscape that aspect of calmness and repose which in nature, as in the works of Claude Lorraine and Poussin, arises from the harmony of forms and colours.
Cruzero, the powerful chief of the Guaypunaves, long resided behind the mountains of Sipapo, after having quitted with his warlike horde the plains between the Rio Inirida and the Chamochiquini. The Indians told us that the forests which cover the Sipapo abound in the climbing plant called vehuco de maimure. This species of liana is celebrated among the Indians, and serves for making baskets and weaving mats. The forests of Sipapo are altogether unknown, and there the missionaries place the nation of the Rayas,* whose mouths are believed to be in their navels.