It is gratifying to reflect that, probably more than to any other outside influence, it was due to the publication of the report of an expedition undertaken in 1851 by William Lewis Herndon, a lieutenant in the United States Navy, and to the explorations of Louis Agassiz, a Harvard professor, that the interest was aroused which at last brought this about. Lieutenant Herndon, like Orellana, started from Lima, and, braving the passes of the Andes, entered the Amazon from one of its western affluents and made the journey in a canoe, with only a Peruvian guide and a few Indian rowers, all the way to its mouth. Professor Agassiz, whose explorations were begun fifteen years later, started from Belém and traveled in a steamboat, such as it was, accompanied by his wife and a corps of scientists, and was given every assistance possible by the late Emperor Dom Pedro, who took a lively interest in the expedition. But even then in Brazil, the Professor says in his book, “so little was known of the Amazon that we could obtain only very meager, and usually rather discouraging, information concerning our projected journey. In Rio, if you say you are going to ascend their great river, your Brazilian friends look at you with compassionate wonder. You are threatened with sickness, with intolerable heat, with mosquitoes, _jacaraes_ (alligators), and wild Indians.” Lieutenant Herndon, however, had already made known to the scientific world that the climate is healthful, notwithstanding the mosquitoes; that, humid and hot as it is during certain hours of the day, the nights are always cool, and that “the direct rays of the sun are tempered by an almost constant east wind, laden with moisture from the ocean, so that no one ever suffers from the heat;” and, when he got back to Rio de Janeiro, Professor Agassiz assured the Brazilians that this was so. Arthur Dias indignantly protests (in his _Brazil of To-day_) that “it is not true, as they say, that the climate of this region prevents the existence and the extending of the population.” “It is a legend, a fiction,” he adds. Mozans, who made a similar journey to Herndon’s very recently, also testifies to the same effect.