Some of the Missionaries in their writings have alleged that the inhabitants of Atures and Maypures have been struck with deafness by the noise of the Great Cataracts, but this is untrue. When the noise is heard in the plain that surrounds the mission, at the distance of more than a league, you seem to be near a coast skirted by reefs and breakers. The noise is three times as loud by night as by day, and gives an inexpressible charm to these solitary scenes. What can be the cause of this increased intensity of sound, in a desert where nothing seems to interrupt the silence of nature? The velocity of the propagation of sound, far from augmenting, decreases with the lowering of the temperature. The intensity diminishes in air agitated by a wind which is contrary to the direction of the sound; it diminishes also by dilatation of the air, and is weaker in the higher than in the lower regions of the atmosphere, where the number of particles of air in motion is greater in the same radius. The intensity is the same in dry air, and in air mingled with vapours; but it is feebler in carbonic acid gas than in mixtures of azote and oxygen. From these facts, which are all we know with any certainty, it is difficult to explain a phenomenon observed near every cascade in Europe, and which, long before our arrival in the village of Atures, had struck the missionary and the Indians.
It may be thought that, even in places not inhabited by man, the hum of insects, the song of birds, the rustling of leaves agitated by the feeblest winds, occasion during the day a confused noise, which we perceive the less because it is uniform, and constantly strikes the ear. Now this noise, however slightly perceptible it may be, may diminish the intensity of a louder noise; and this diminution may cease if during the calm of the night the song of birds, the hum of insects, and the action of the wind upon the leaves be interrupted. But this reasoning, even admitting its justness, can scarcely be applied to the forests of the Orinoco, where the air is constantly filled by an innumerable quantity of mosquitos, where the hum of insects is much louder by night than by day, and where the breeze, if ever it be felt, blows only after sunset.
I rather think that the presence of the sun acts upon the propagation and intensity of sound by the obstacles met in currents of air of different density, and by the partial undulations of the atmosphere arising from the unequal heating of different parts of the soil. In calm air, whether dry or mingled with vesicular vapours equally distributed, sound-waves are propagated without difficulty. But when the air is crossed in every direction by small currents of hotter air, the sonorous undulation is divided into two undulations where the density of the medium changes abruptly; partial echoes are formed that weaken the sound, because one of the streams comes back upon itself; and those divisions of undulations take place of which M. Poisson has developed the theory with great sagacity.* (* Annales de Chimie tome 7 page 293.) It is not therefore the movement of the particles of air from below to above in the ascending current, or the small oblique currents that we consider as opposing by a shock the propagation of the sonorous undulations. A shock given to the surface of a liquid will form circles around the centre of percussion, even when the liquid is agitated. Several kinds of undulations may cross each other in water, as in air, without being disturbed in their propagation: little movements may, as it were, ride over each other, and the real cause of the less intensity of sound during the day appears to be the interpretation of homogeneity in the elastic medium. During the day there is a sudden interruption of density wherever small streamlets of air of a high temperature rise over parts of the soil unequally heated. The sonorous undulations are divided, as the rays of light are refracted and form the mirage wherever strata of air of unequal density are contiguous. The propagation of sound is altered when a stratum of hydrogen gas is made to rise in a tube closed at one end above a stratum of atmospheric air; and M. Biot has well explained, by the interposition of bubbles of carbonic acid gas, why a glass filled with champagne is not sonorous so long as that gas is evolved, and passing through the strata of the liquid.
In support of these ideas, I might almost rest on the authority of an ancient philosopher, whom the moderns do not esteem in proportion to his merits, though the most distinguished zoologists have long rendered ample justice to the sagacity of his observations. "Why," says Aristotle in his curious book of Problems, "why is sound better heard during the night? Because there is more calmness on account of the absence of caloric (of the hottest).* (* I have placed in a parenthesis, a literal version of the term employed by Aristotle, to express in reality what we now term the matter of heat. Theodore of Gaza, in his Latin translation, expresses in the shape of a doubt what Aristotle positively asserts. I may here remark, that, notwithstanding the imperfect state of science among the ancients, the works of the Stagirite contain more ingenious observations than those of many later philosophers. It is in vain we look in Aristoxenes (De Musica), in Theophylactus Simocatta (De Quaestionibus physicis), or in the 5th Book of the Quest. Nat. of Seneca, for an explanation of the nocturnal augmentation of sound.) This absence renders every thing calmer, for the sun is the principle of all movement." Aristotle had no doubt a vague presentiment of the cause of the phenomenon; but he attributes to the motion of the atmosphere, and the shock of the particles of air, that which seems to be rather owing to abrupt changes of density in the contiguous strata of air.
On the 16th of April, towards evening, we received tidings that in less than six hours our boat had passed the rapids, and had arrived in good condition in a cove called el Puerto de arriba, or the Port of the Expedition. We were shown in the little church of Atures some remains of the ancient wealth of the Jesuits. A silver lamp of considerable weight lay on the ground half-buried in the sand. Such an object, it is true, would nowhere tempt the cupidity of a savage; yet I may here remark, to the honor of the natives of the Orinoco, that they are not addicted to stealing, like the less savage tribes of the islands in the Pacific. The former have a great respect for property; they do not even attempt to steal provision, hooks, or hatchets. At Maypures and Atures, locks on doors are unknown: they will be introduced only when whites and men of mixed race establish themselves in the missions.
The Indians of Atures are mild and moderate, and accustomed, from the effects of their idleness, to the greatest privations. Formerly, being excited to labour by the Jesuits, they did not want for food. The fathers cultivated maize, French beans (frijoles), and other European vegetables; they even planted sweet oranges and tamarinds round the villages; and they possessed twenty or thirty thousand head of cows and horses, in the savannahs of Atures and Carichana. They had at their service a great number of slaves and servants (peones), to tend their herds. Nothing is now cultivated but a little cassava, and a few plantains. Such however is the fertility of the soil, that at Atures I counted on a single branch of a musa one hundred and eight fruits, four or five of which would almost have sufficed for a man's daily food. The culture of maize is entirely neglected, and the horses and cows have entirely disappeared. Near the raudal, a part of the village still bears the name of Passo del ganado (ford of the cattle), while the descendants of those very Indians whom the Jesuits had assembled in a mission, speak of horned cattle as of animals of a race now lost. In going up the Orinoco, toward San Carlos del Rio Negro, we saw the last cow at Carichana. The Fathers of the Observance, who now govern these vast countries, did not immediately succeed the Jesuits. During an interregnum of eighteen years, the missions were visited only from time to time, and by Capuchin monks. The agents of the secular government, under the title of Royal Commissioners, managed the hatos or farms of the Jesuits with culpable negligence. They killed the cattle for the sake of selling the hides. Many heifers were devoured by the jaguars, and a great number perished in consequence of wounds made by the bats of the raudales, which, though smaller, are far bolder than the bats of the Llanos. At the time of the expedition of the boundaries, horses from Encaramada, Carichana, and Atures, were conveyed as far as San Jose de Maravitanos, where, on the banks of the Rio Negro, the Portuguese could only procure them, after a long passage, and of a very inferior quality, by the rivers Amazon and Grand Para. Since the year 1795, the cattle of the Jesuits have entirely disappeared. There now remain as monuments of the ancient cultivation of these countries, and the active industry of the first missionaries, only a few trunks of the orange and tamarind, in the savannahs, surrounded by wild trees.
The tigers, or jaguars, which are less dangerous for the cattle than the bats, come into the village at Atures, and devour the swine of the poor Indians. The missionary related to us a striking instance of the familiarity of these animals, usually so ferocious. Some months before our arrival, a jaguar, which was thought to be young, though of a large size, had wounded a child in playing with him. The facts of this case, which were verified to us on the spot, are not without interest in the history of the manners of animals. Two Indian children, a boy and a girl, about eight and nine years of age, were seated on the grass near the village of Atures, in the middle of a savannah, which we several times traversed. At two o'clock in the afternoon, a jaguar issued from the forest, and approached the children, bounding around them; sometimes he hid himself in the high grass, sometimes he sprang forward, his back bent, his head hung down, in the manner of our cats. The little boy, ignorant of his danger, seemed to be sensible of it only when the jaguar with one of his paws gave him some blows on the head. These blows, at first slight, became ruder and ruder; the claws of the jaguar wounded the child, and the blood flowed freely. The little girl then took a branch of a tree, struck the animal, and it fled from her. The Indians ran up at the cries of the children, and saw the jaguar, which then bounded off without making the least show of resistance.
The little boy was brought to us, who appeared lively and intelligent. The claw of the jaguar had torn away the skin from the lower part of the forehead, and there was a second scar at the top of the head. This was a singular fit of playfulness in an animal which, though not difficult to be tamed in our menageries, nevertheless shows itself always wild and ferocious in its natural state. If we admit that, being sure of its prey, it played with the little Indian as our cats play with birds whose wings have been clipped, how shall we explain the patience of a jaguar of large size, which finds itself attacked by a girl? If the jaguar were not pressed by hunger, why did it approach the children at all? There is something mysterious in the affections and hatreds of animals. We have known lions kill three or four dogs that were put into their den, and instantly caress a fifth, which, less timid, took the king of animals by the mane. These are instincts of which we know not the secret.
We have mentioned that domestic pigs are attacked by the jaguars. There are in these countries, besides the common swine of European race, several species of peccaries, or pigs with lumbar glands, two of which only are known to the naturalists of Europe. The Indians call the little peccary (Dicotiles torquatus, Cuv.), in the Maypure tongue, chacharo; while they give the name of apida to a species of pig which they say has no pouch, is larger, and of a dark brown colour, with the belly and lower jaw white. The chacharo, reared in the houses, becomes tame like our sheep and goats. It reminds us, by the gentleness of its manners, of the curious analogies which anatomists have observed between the peccaries and the ruminating animals. The apida, which is domesticated like our swine in Europe, wanders in large herds composed of several hundreds. The presence of these herds is announced from afar, not only by their hoarse gruntings, but above all by the impetuosity with which they break down the shrubs in their way. M. Bonpland, in an herborizing excursion, warned by his Indian guide to hide himself behind the trunk of a tree, saw a number of these peccaries (cochinos or puercos del monte) pass close by him. The herd marched in a close body, the males proceeding first; and each sow was accompanied by her young. The flesh of the chacharo is flabby, and not very agreeable; it affords, however, a plentiful nourishment to the natives, who kill these animals with small lances tied to cords. We were assured at Atures, that the tiger dreads being surrounded in the forests by these herds of wild pigs; and that, to avoid being stifled, he tries to save himself by climbing up a tree. Is this a hunter's tale, or a fact that has really been observed? In several parts of America the hunters believe in the existence of a javali, or native boar with tusks curved outwardly. I never saw one, but this animal is mentioned in the works of the Spanish missionaries, a source too much neglected by zoologists; for amidst much incorrectness and extravagance, they contain many curious local observations.
Among the monkeys which we saw at the mission of the Atures, we found one new species, of the tribe of sais and sajous, which the Creoles vulgarly call machis. It is the Guvapavi with grey hair and a bluish face. It has the orbits of the eyes and the forehead as white as snow, a peculiarity which at first sight distinguishes it from the Simia capucina, the Simia apella, the Simia trepida, and the other weeping monkeys hitherto so confusedly described. This little animal is as gentle as it is ugly. A monkey of this species, which was kept in the courtyard of the missionary, would frequently mount on the back of a pig, and in this manner traverse the savannahs. We have also seen it upon the back of a large cat, which had been brought up with it in Father Zea's house.