Du Chaillu was brought prominently before the American public by a series of striking and interesting articles on the Gaboon country, which from their favorable reception strengthened his belief in the importance of thoroughly exploring certain portions of the west coast of Africa. The region selected for his investigations was under the burning sun of the equator, somewhat to the north of the Congo country, in the basins drained by the Muni, Ogowe, and Rembo Rivers, which, owing to difficulty of access, extreme heat, prevailing fevers, and deadly climate, were practically unknown. Between 1856 and 1859 Du Chaillu journeyed upward of eight thousand miles through this country, travelling on foot, with no white companion, and, with the aid of natives, cursorily explored nearly one hundred thousand square miles of virgin territory. Working with the ardent zeal of a naturalist, his enormous ornithological collection aggregated thousands of specimens, and in this collection alone he added some sixty new species of birds to the domain of science. Among the quadrupeds, he discovered no less than twenty new species, and among the most important animals brought to light were the very remarkable nest-building ape, with its unknown and its almost equally extraordinary brother the koo-loo-lamba, and his observations of the almost unknown gorilla were most interesting and valuable. In ethnology he accumulated a number of invaluable native arms and implements, which now adorn the British Museum. Space fails in which to recite his intense sufferings, during these explorations, from semi-starvation, the wild beasts of the dense forests, the venomous reptiles of the river valleys, the attacks of ferocious ants, and other intolerable poisonous insects which infest the interior. There are many interesting accounts of curious quadrupeds in Du Chaillu's book, "Adventures in Equatorial Africa," but none appeals more strongly to most readers than that of the gorilla. Traditions from antiquity, the relation of Hanno, the Carthaginian navigator of 350 B.C., set forth the existence of such an animal, but no white man had ever seen a gorilla, except Andrew Battell, early in the seventeenth century. Nearly ten years before the explorations of Du Chaillu the gorilla had been, however, brought to the notice of naturalists by Dr. Savage, of Boston, who had received a skull from the Rev. J. L. Wilson, an American missionary on the Gaboon. From boyhood up Du Chaillu had heard from the natives of Gaboon fearful stories of the cunning, strength, and ferocity of this ape, which is the most dreaded animal on the west coast of Africa. For years he had longed for an opportunity to hunt the gorilla, and when he first saw its tracks, which threw his native hunters into alarm, he relates that his sensations were indescribable, his feelings so intense as to be painful, and his heart-throbs so violent that he actually feared the animal would be alarmed by them.