Singular Birds of Maldonado.

45

already begun to think seriously of the great prob lems to which he devoted his life in later years.

Among the birds at Maldonado Darwin noticed one resembling a starling, which had a peculiar habit of sitting upon the backs of horses or cattle and pluming its feathers. It was interesting to him for

another reason: Azara had ascribed to it the cuckoolike habit of depositing its eggs in the nests of other birds. Darwin found that the same was true of the South American ostrich, which laid its eggs in the nests of others indiscriminately.

Of all the singular birds seen here the Polyborus chamango was perhaps the most interesting. It was a carrion feeder, and Darwin often saw several within the ribs of the skeleton of a horse. They were extremely savage, pouncing upon dogs, seizing rabbits. as they came from their holes, and even tearing the leather from the rigging of the ship in what appeared mere destructiveness. One was seen to carry off a heavy bolas, while another seized a large glazed hat belonging to a sailor and bore it nearly a mile from the ship; a small compass in a red morocco case shared the same fate, and was not recovered.

As we have seen, Darwin found the mouth of the Plata famous for its electrical disturbances, and in the sand-banks here he discovered some curious evidences of the frequency of the bolts. Protruding from the sand heaps were numerous vitrified and siliceous tubes formed as the lightning entered the loose sand. The sand was continually being blown about by the wind, thus exposing the tubes; similar ones in other places have been traced for thirty feet.

Darwin found that the internal surface was smooth and completely vitrified. The walls of the tube were about the twentieth of an inch in thickness. The most remarkable feature about this was the number of tubes in so restricted an area. The en

tire region bore a bad name. In a single electrical storm thirty-seven places were struck in the city of Buenos Ayres and nineteen persons killed.

In referring to this Darwin says: “I am inclined to suspect that thunder-storms are very common near the mouths of great rivers. Is it not possible that the mixture of large bodies of fresh and salt water may disturb the electrical equilibrium? Even during our occasional visits to this part of South America, we heard of a ship, two churches, and a house having been struck. Both the church and the house I saw shortly afterwards: the house belonged to Mr. Hood, the consul-general at Monte Video. Some of the effects were curious: the paper, for nearly a foot on each side of the line where the bellwires had run, was blackened. The metal had been fused, and although the room was about fifteen feet high, the globules, dropping on the chairs and furniture, had drilled in them a chain of minute holes. A part of the wall was shattered as if by gunpowder, and the fragments had been blown off with force sufficient to dent the wall on the opposite side of the room. The frame of a looking-glass was blackened, and the gilding must have been volatilised, for a smelling-bottle, which stood on the chimney-piece, was coated with bright metallic particles, which adhered as firmly as if they had been enamelled."

The Rio Negro-Trips into the Interior-The Sacred Tree-Superstition of Natives-Salt Lakes-Bahia Blanca-A Tomb of Giants-The Mylodon Darwinii-The Armadillo-Hibernation -Careful Work-War-General Rosas-Brutal Natives-Skilled Equestrians.

ROM Maldonado the Beagle sailed south, arriving at the mouth of the Rio Negro in August, 1833. Here Darwin found a newer and more interesting field for work, and applied himself assiduously to the investigation of the local fauna and flora. Nothing escaped his watchful eye, and he

not only collected but made careful observations regarding the habits of the various animals, all of which were recorded in the growing log-book, which was to prove such a treasure-house of zoological facts in the future.

He made his headquarters for his land expeditions at El Carmen, about eighteen miles up the river, a town built on the face of a high cliff, some of the houses or homes of the natives being excavated in its face. One of the first objects of interest to attract his attention was a famous salt lake. During the rainy season it was a basin of the strongest brine, but when the dry time came, and the hot summer sun poured down, the water evaporated, leaving a pure white patch of gleaming salt, in remarkable contrast to the surrounding verdure.

This lake was found to be two miles in length, with a layer of salt ranging in thickness from several inches at the border to as many feet in the centre. The interest of the explorer naturally centred in the life of the lake, and he was repaid by the discovery of a worm that existed in sufficient quantities to attract flamingoes here to feed. “Well may we affirm," writes Darwin in his log-book, "that every part of the world is habitable! Whether lakes of brine, or those subterranean ones hidden beneath volcanic mountains-warm mineral springs-the wide expanse and depths of the ocean-the upper regions of the atmosphere, and even the surface of perpetual snow--all support organic beings."

During a trip to the Colorado River with a band of Gauchos Darwin came upon the sacred tree, about which so much has been said and written, it having been described as taking up foreign objects upon its branches. The tree is a low thorny variety, not common, yet conspicuous on the plains by its peculiar appearance. As the party approached, the tree was

A Tomb of Giants.

49

seen to be leafless, the branches being covered by hundreds of objects, the offerings of the Indians, who reverenced it as the altar of Walleechu, such as cigars, pieces of cloth, bits of meat, strings, fruit, and a variety of singular articles. Around the tree was a circle of bones, the sacrifices of horses, which the Indians had made. The Gauchos, though ignorant, as we have seen, looked with contempt upon the tree, and said that they had often witnessed the ceremonies of the Indians, waiting until the latter had disappeared, to help themselves to such articles. as possessed any value.

The young naturalist here first encountered the agouti, and he notes it as a singular fact that, while in 1670 the animal was found much farther to the south, it now occupied a restricted area.

From Bahia Blanca, which was reached in the latter part of August, Darwin travelled overland to Buenos Ayres. The former was one of the most interesting localities he had visited, as here he discovered a veritable tomb of the lost races of a former age. Upon the beach, within an area of two hundred yards, he took out, after no little labour, the remains of nine large quadrupeds. They included the megatherium—a sloth-like animal, the megalonyx— an allied form, the scelidotherium-an animal as large as a rhinoceros, with a head, according to Professor Owen, who described the remains, resembling that of the Cape ant-eater, or the armadillos. Besides these, he found another giant, which when described was named after him, Mylodon Darwinii; also a gigantic armadillo, with a colossal armour, separated