The results of his four years of research in the interests of ethnography, geography, and natural history, were placed before the public in a valuable work entitled "Explorations and Adventures in Equatorial Africa." The book gave rise to bitter, harsh, unjust criticisms, and engendered endless discussions. Du Chaillu's journey to the interior was entirely discredited, and his accounts of the animals and natives were characterized as mere fabrications. Discoveries necessarily develop discrepancies between the realities brought to light and existing beliefs produced through inference or imagination; then, as has many another discover in science or geography, Du Chaillu learned how slow is the willingness of a jealous mind to relinquish its favorite error for a conflicting truth. Justification came speedily, for the explorations of Serval and Bellay, of the very next year, proved the accuracy of Du Chaillu's account of the great Ogowe River, and indicated the general correctness of his map of the Ashira country. Burton confirmed his reports regarding the cannibalistic habits of the Fans, and other statements were speedily corroborated. Stung to the quick by the adverse criticisms, Du Chaillu, although suffering from the effects of fevers contracted in his long residence in Western Africa, determined to repeat the journey with such precautions regarding his observations as would be absolutely convincing as to their truthfulness; especially he determined to capture and bring to Europe a living gorilla. To ensure accuracy he went through a course of instruction in the use of instruments, learning to make, test, and reduce astronomical and hypsometrical observations, and acquired proficiency in the then difficult art of photography. As regards geographical explorations he had a vague hope that he might reach from the west coast of Africa some unknown tributary of the Nile, down which he might be able to reach the main river and the Mediterranean Sea. Leaving England in August, 1863, Du Chaillu's first destination was the mouth of Fernand Vaz River, about one hundred and ten miles south of the Gaboon, this point being selected both because he knew the natives and also because that river valley being unknown afforded him virgin ground from the beginning of his journey. In landing through the terrible surf that makes entrance into the Fernand Vaz so dangerous, Du Chaillu was nearly drowned and all his astronomical instruments and medicines were lost or damaged. This necessitated his delay in that region until other instruments could be had from England; but the time was not lost, for he had ample opportunity of further studying the habits of the gorillas, which abound there; fortunately he captured four, an adult and three young, one of which he shipped alive to London, but it died during the voyage. [Illustration: A Village of Dwarfs.]