Memoir on a new Species of Pimelodus thrown out of the Volcanoes in the Kingdom of Quito; with some Particulars respecting the Volcanoes of the Andes. By M. De Humboldt . From Recueil d'Observations de Zoologie et d'Anatomie compare, 1re livraison. The chain of the Andes, from the Straits of Magellan to the northern shores bordering on Asia, extending over more than 2000 leagues, presents above fifty volcanoes still active, of which the phaenomena are as various as their height and local situation. A small number of the least elevated of these volcanoes throw out running lava. I have seen, at the volcano of Zurullo, in Mexico, a basaltic cone that sprung from the earth the 15th September 1759, and at present rising 249 toises (1595 [Formel] feet) above the surrounding plain. The volcanic ridges of Guatimala cast out a prodigious quantity of muriate of ammonia. Those of Popayan and the high plain of Pasto present either solfatares, which exhale sulphureous acid, or little craters filled with boiling water, and disengaging sulphurated hydrogen, which decomposes by contact with the oxygen of the atmosphere. The volcanoes of the kingdom of Quito throw out pumicestone, basaltes , and scorified porphyries; and vomit enormous quantities of water, carburetted argil, and muddy matter, which spreads fertility from eight to ten leagues around. But, since the period to which the traditions of the natives ascend, they have never produced great masses of running melted lava. The height of these colossal mountains, that surpasses five times that of Vesuvius, and their inland situation, are, without doubt, the principal causes of these anomalies. The subterranean noise of Cotopaxi, at the time of its great explosions, extends to distances equal to that from Vesuvius to Dijon. But, notwithstanding this intensity of force, it is known, that if the volcanic fire was at a great depth, the melted lava could neither raise itself to the edge of the crater, nor pierce the flank of these mountains, which to the height of 1400 toises (8971 [Formel] feet) are fortified by high surrounding plains. It appears, therefore, natural, that volcanoes so elevated should discharge from their mouth but isolated stones, volcanic cinders or ashes, flames, boiling water, and, above all, this carburetted argil impregnated with sulphur, that is called moya in the language of the country. It would have been of some use to geology had the author here mentioned whether the stone which he calls basaltes has been submitted to the action of fire or water; or whether, in addition to the other well known characters of this mineral, it yielded hydrogen gas on distillation, the latter being the peculiar characteristic of what is properly denominated basaltes.-- Translator. M. Humboldt seems not to have been aware that this name has been affixed to it in consequence of its having some resemblance to a kind of blackish coarse bread made of grits or pollard, and used in Spain by some very poor but proud people, or for purposes of penitence in cases of a pecado mortal.--Translator. The mountains of the kingdom of Quito occasionally offer another spectacle, less alarming, but not less curious to the naturalist. The great explosions are periodical, and somewhat rare. Cotopaxi, Tungurahua, and Sangay, sometimes do not present one in twenty or thirty years. But during such intervals even these volcanoes will discharge enormous quantities of argillaceous mud; and, what is more extraordinary, an innumerable quantity of fish. By accident, none of these volcanic inundations took place the year that I passed the Andes of Quito; but the fish vomited from the volcanoes is a phaenomenon so common, and so generally known by all the inhabitants of that country, that there cannot remain the least doubt of its authenticity. As there are in these regions several very well informed persons, who have successfully devoted themselves to the physical sciences, I have had an opportunity of procuring exact information (renseignemens) respecting these fishes. M. de Larrea, at Quito, well versed in the study of chemistry, who has formed a cabinet of the minerals of his country, has been, above all others, the most useful to me in these researches. Examining the archives of several little towns in the neighbourhood of Cotopaxi, in order to extract the epochs of the great earthquakes, that fortunately have been preserved with care, I there found some notes on the fish ejected from the volcanoes. On the estates of the marquis of Selvalegre the Cotopaxi had thrown a quantity so great, that their putrefaction spread a fetid odour around. In 1691 the almost extinguished volcano of Imbaburu threw out thousands on the fields in the environs of the city of Ibarra. The putrid fevers which commenced at that period were attributed to the miasma which exhaled from these fish, heaped on the surface of the earth and exposed to the rays of the sun. The last time that Imbaburu ejected fish was on the 19th of June 1698, when the volcano of Cargneirazo sunk, and thousands of these animals enveloped in argillaceous mud were thrown over the crumbling borders. The Cotopaxi and Tungurahua throw out fish, sometimes by the crater which is at the top of these mountains, sometimes by lateral vents, but constantly at 2500 or 2600 toises above the level of the sea: the adjacent plains being 1300 toises high, one may conclude that these animals issue from a point which is 1300 toises more elevated than the plains on which they are thrown. Some Indians have assured me that the fish vomited by the volcanoes were sometimes still living in descending along the flank of the mountain: but this fact does not appear to me sufficiently proved: certain it is, that among the thousands of dead fish that in a few hours are seen descending from Cotopaxi with great bodies of cold fresh water, there are very few that are so much disfigured that one can believe them to have been exposed to the action of a strong heat. This fact becomes still more striking when we consider the soft flesh of these animals, and the thick smoke which the volcano exhales during the eruption. It appeared to me of very great importance to descriptive natural history to verify sufficiently the nature of these animals. All the inhabitants agree that they are identical with those which are found in the rivulets at the foot of these volcanoes, and called prennadillas : they are even the only species of fish that is discovered at the height of above 1400 toises in the waters of the kingdom of Quito. I have designed it, with care, on the spot, and my design has been coloured by M. Turpin. I have observed that the prennadilla is a new species of the genus silurus. M. Lacepede, who has also examined it, advised me to place it in that division of silurus which, in the fifth volume of his Natural History of Fishes, he has described under the name of pimelodes. This word is an indifferent or contemptuous diminutive, indicating abundant, pregnant, fruitful, easily taken, but not a pleasing or desirable object. The name is purely Spanish and not Indian, of course could never have been applied to any fish used as food by Spaniards.--Translator. This new species of pimelodus has a depressed body of an olive colour mixed with little black spots. The mouth, which is at the extremity of the nose, is very large, and furnished with two barbillons or whiskers attached to the jaws. The nostrils are tubulous; the eyes are very small, and placed towards the middle of the head. The skin of the body and the tail is covered with an abundant mucus, and the mouth is furnished with very small teeth. The branchial membrane has four radii, like the pimelodus chilensis; the pectoral fin has nine; the ventral five; the first dorsal six; the fin of the anus seven; and that of the tail, which is bifid, has twelve radii. The first radius of all the fins is indented on the outside: the second dorsal fin is adipose, and placed near the tail. This little pimelodus, which is found in lakes even to the height of 1700 toises, is, without doubt, the fish that lives in the most elevated regions of our globe. Its common length scarcely amounts to ten centimetres (four inches); but there are varieties which do not appear to reach five centimetres (two inches) in length. In the system of ichthyology this new species of pimelodus should be ranged in the first sub-genus established by Lacepede, among the forked-tailed pimelodes. It must be in the first species, before the pimelodus bagre. As it is the only one of that division that has but two whiskers, I give it the name of PIMELODUS Cyclopum. (Plate VIII.) Cirris duobus, corpore olivaceo nigro-punctato. This little fish lives in rivulets at the temperature of 10° of the centigrade thermometer, while other species of the same genus exist in rivers in the plains the water of which is at 27°. The pimelodus is but very rarely eaten, and then only by the most indigent race of Indians; its aspect and the sliminess of its skin render it very disgusting. From the enormous quantity of pimelodes that the volcanoes of the kingdom of Quito occasionally discharge, one cannot doubt that country contains great subterranean lakes which conceal these fishes; for the individuals that exist in the little rivers around are very few in number. A part of those rivers may communicate with the subterranean pits: it is also probable that the first pimelodes which have inhabited these pits have mounted there against the current. I have seen fish in the caverns of Derbyshire, in England; and near Gailenreuth, in Germany, where the fossil heads of bears and lions are found, there are living trouts in the grottoes, which at present are very distant from any rivulet, and greatly elevated above the level of the neighbouring waters. In the province of Quito, the subterraneous roarings that accompany the earthquakes; the masses of rocks that we think we hear crumbling down below the earth we walk on; the immense quantity of water that issues from the earth in the driest places during the volcanic explosions; and numerous other phaenomena, indicate that all the soil of this elevated plain is undermined. But, if it is easy to conceive that vast subterranean basins may be filled with water which nourishes fishes, it is more difficult to explain how these animals are attracted by volcanoes that ascend to the height of 1300 toises, and discharged either by their craters or by their lateral vents. Should we suppose that the pimelodes exist in subterranean basins of the same height at which they are seen to issue? How conceive their origin in a position so extraordinary; in the flank of a cone so often heated, and perhaps partly produced by volcanic fire? Whatever may be the source from which they issue, the perfect state in which they are found induces us to believe that those volcanoes, the most elevated and the most active in the world, experience, from time to time, convulsive movements, during which the disengagement of caloric appears less considerable than we should suppose it. Earthquakes do not always accompany those phaenomena. Perhaps, in the different concamerations that may be admitted in the interior of a volcano, the air is found occasionally condensed, and that it is this condensed air which contributes to raise the water and fish; perhaps they issue from a concavity distant from those which emit volcanic fire; possibly, in fine, the argillaceous mud in which those animals are enveloped defends them from the action of great heat. Notwithstanding all the researches that have been recently made on volcanoes, there is nothing but the study of volcanic productions that has made any progress. As to the nature of the combustibles which nourish those subterranean fires, and the mode of action of those fires themselves, I believe that all persons who have visited the borders of craters, and who have lived a long time in the vicinity of volcanoes, will sincerely avow, with me, that we are still very far from being able to give an explication, which, without being contrary to the principles of chemistry and of physics, could account for the great phaenomena which volcanic explosions present. The corregidor of the city of Ibarra, don Jose Pose Pardo, has communicated to me an interesting observation on the pimelodes. "It is known (says he, in a letter which I have still preserved,) that the volcano of Imbaburu, at the time of its great eruption on the side next our city, threw out an enormous quantity of prennadillas: it even continues still occasionally to do so, especially after great rains. It is observed that these fishes actually live in the interior of the mountain, and that the Indians of S. Pabla fish for them in a rivulet at the very place whence they issue from the rock. This fishery does not succeed either in the day or in moonlight: a very dark night is therefore necessary, as the prennadillas will not otherwise come out of the volcano, the interior of which is hollow." It appears, then, that the light is injurious to those subterranean fishes, which are not accustomed to so strong a stimulus: an observation so much the more curious, that the pimelodes of the same species, which inhabit the brooks in the vicinity of the city of Quito, live exposed to the brightness of the meridian sun. This is an assertion somewhat contrary to that of their being very bad food, and disagreeable in appearance. It is within the particular knowledge of the translator, that the Spaniards of South America are both very sceptical and very witty, and that to play upon the philosophical faith of Europeans would be their highest delight. He must therefore be pardoned for regarding the letter of el Senor Corregidor as a jeu d'esprit en revanche for the sarcastic observations of French travellers on the Spaniards.--Translator. Abbildungen