All things being thus prepared, they departed from Guayaquil, and embarked on the river on the 3d of May, 1736. The extreme velocity and strength of the current, and several unfortunate accidents, so greatly retarded their progress, that they did not reach Caracol before the 11th. “The tortures we received on the river, from the mosquitoes,” says Ulloa, “were beyond imagination. We had provided ourselves with quetres and mosquito-cloths; but to very little purpose: the whole day we were in continual motion to keep them off; but at night our torments were excessive. Our gloves were indeed some defence to our hands, but our faces were entirely exposed; nor were our clothes a sufficient defence for the rest of our bodies, for their stings penetrating through the cloth, caused a very painful and fiery itching. The most dismal night we spent on this passage, was when we came to an anchor near a large and handsome house, but uninhabited; for we had no sooner seated ourselves in it, than we were attacked on all sides with innumerable swarms of mosquitoes, so that we were so far from having any rest there, that it was impossible for a person susceptible of feeling to be one moment quiet. Those who had covered themselves with their mosquito-cloths, after taking care that none of these malignant insects were contained in them, found themselves in a moment so attacked on all sides that they were obliged soon to return to the place they had quitted. Those who were in the house, hoping that they should find some relief in the open fields, ventured out, though in danger of suffering in a more terrible manner from the serpents; but were soon convinced of their mistake, it being impossible to determine which was the more desirable place, within the mosquito-cloth, without it, or in the open fields. In short no expedient was of any use against their numbers. The smoke of the trees we burnt to disperse these infernal insects, besides almost choking us, seemed rather to augment than diminish their numbers. At daybreak we could not without concern look at each other.” At Caracol they quitted the river, and continued their journey on the backs of mules, through thick forests, along the course of the river Ojibar. When, as frequently happened, they found no habitation near their halting-place, the inconvenience was soon remedied by the remarkable dexterity of their Indians, who running into the woods, quickly returned with branches of trees and vijahna leaves, with which, in less than an hour, they erected several huts large enough to contain the whole party, and so well contrived that the rain, which fell in torrents, could not penetrate them. They now began to ascend the distant roots of the mountains, and felt an increasing coldness in the air. At a place called Mamarumi, or the “Mother of Stone,” they beheld an indescribably beautiful cascade.