It here becomes necessary to say something of the translators, and the cause of so much unexpected delay in producing this volume; the more so as many of the subscribers to the Scientific Library have expressed an interest in the subject, owing, in some measure, to a controversy which arose out of my previous publication of _Cosmos_. The translation was originally entrusted to E. C. Otté, with an agreement as to time, according to which I had every reason to expect that I should fulfil my engagement to publish it in October last, or at latest in November; but, after much of the manuscript was prepared, the translator’s indisposition and subsequent absence from London, occasioned a serious suspension. In this dilemma I found it necessary to call in aid, as well as to assist personally. The result of this “co-operation of forces” will no doubt prove satisfactory to the reader, inasmuch as every sheet has been at least trebly revised, and it is hoped proportionably improved. In addition to the responsible translator, my principal collaborateur has been Mr. E. H. Whitelocke, a gentleman well qualified for the task. All the measurements are calculated by the scientific friend, who fulfilled this department so satisfactorily in my edition of _Cosmos_. The translation of the pretty poem, _The Parrot of Atures_, (page 189,) now first given in English, is contributed by Mr. Edgar A. Bowring. For the additional notes subscribed “ED.” I am myself, in most instances, responsible. Much has been said, pro and con, about the sanction of the Author to the several translations of his works. My answer has, I believe, been generally considered satisfactory and conclusive. I have now only to add, that when I wrote to Baron Humboldt, more than a year and a-half ago, presenting him with my then unpublished edition of _Cosmos_, I announced my intention of proceeding with his other works, and consulted him on the subject. He replied in the kindest spirit, without intimating any previous engagement, and honoured me with several valuable suggestions. A portion of one of his letters is annexed in fac-simile. In consequence of what I then presumed to be his recommendation, I determined to make the _Ansichten_ my next volume, and announced it, long before any one else, though not at first by its English name. At that time I had reason to hope that I should receive the new German edition at least as early as any one, but was disappointed. This circumstance, added to the delay already alluded to, has brought me late into the field. In now, however, presenting my subscribers with what I have taken every available means to render a perfect book, I hope I shall afford them ample atonement.