One word as to the manner in which this volume has grown into its present shape, for it has been rather the natural growth of circumstances than the result of any preconceived design. Partly for the entertainment of her friends, partly with the idea that I might make some use of it in knitting together the scientific reports of my journey by a thread of narrative, Mrs. Agassiz began this diary. I soon fell into the habit of giving her daily the more general results of my scientific observations, knowing that she would allow nothing to be lost which was worth preserving. In consequence of this mode of working, our separate contributions have become so closely interwoven that we should hardly know how to disconnect them, and our common journal is therefore published, with the exception of a few unimportant changes, almost as it was originally written. In this volume I have attempted only to give such an account of my scientific work and its results as would explain to the public what were the aims of the expedition, and how far they have been accomplished. It is my hope to complete a work, already begun, on the Natural History, and especially on the Fishes of Brazil, in which will be recorded not only my investigations during the journey and those of my assistants in their independent excursions, but also the researches now regularly carried on in connection with the immense Brazilian collections stored in the Museum at Cambridge. This must, however, be the slow labor of many years, and can only be published very gradually. In the mean time I hope that this forerunner of the more special reports may serve to show that our year in Brazil, full as it was of enjoyment for all the party, was also rich in permanent results for science. L. AGASSIZ. ----- Footnote 1: There is but one sad record I have to make connected with this journey. My friend and companion of many years, Mr. Burkhardt, died about ten months after his return, of a disease which, though not contracted in Brazil, since it was of some years’ standing, was no doubt aggravated by the hot climate. His great desire to accompany me led him, against my advice, to undertake a journey which, in his case, was a dangerous one. He suffered very much during our stay on the Amazons, but I could not persuade him to leave his work; and in the following pages it will be seen that his industry was unflagging. TABLE OF CONTENTS. CHAPTER I. VOYAGE FROM NEW YORK TO RIO DE JANEIRO. PAGE