resisted, he proposed to Mr. Bates a joint expedition to the Amazons, one of the objects, in addition to the collection of natural history specimens, being to gather facts, as Mr. Wallace expressed it in one of his letters to Mr. Bates, "towards solving the problem of the origin of species," a subject on which they had already conversed and corresponded extensively. The two friends met in London early in 1848 to study the collections of South American animals and plants already there; and they embarked at Liverpool in a small trading vessel on the 2oth of April, 1848, reaching the mouth of the Amazons just a month later. From this date the present volume speaks for itself. We will merely note that Mr. Bates took a different route of exploration from Mr. Wallace from March 1850; he remained seven years longer in the country, and in 1863 published his most attractive "Naturalist on the Amazons."
Mr. Wallace's travels on the Rio Negro and to the upper waters of the Orinoco, his adventurous ascent of the rapid river Uaupés, his observations on the natural history and the native tribes of the Amazon valley, are simply and naturally recorded in this volume. His assemblage of facts will be seen to form a broad basis for induction as to causes and modes of transformation of species. His return voyage bade fair to be his last, for the vessel in which he sailed took fire, and was completely destroyed, with a large proportion of Mr. Wallace's live animals and valuable specimens. Ten anxious days had to be spent in boats, tortured not only by shortness of food but by remembrances of the dangers encountered in obtaining valued specimens, now irretrievably lost. It was only after an eighty days' voyage that Mr. Wallace landed at Deal on the 18th of October, 1852. His "Travels on the Amazon and Rio Negro," published in the autumn of 1853, had an excellent reception, and after disposing of the collections which had been sent home previous to his return Mr. Wallace started for another tropical region, the Malay archipelago.
From July 1854, when he arrived in Singapore, to the early part of 1862, Mr.Wallace travelled many thousand miles, mostly in regions little explored before, especially for natural history purposes. Borneo, Java, Sumatra, Timor, Celebes, the Moluccas, the Aru and Ké islands, and even New Guinea were visited, some more than once, and long sojourns were made in the most interesting regions. Even those who have read his
