Our author has the well deserved reputation of being one of the fullest authorities for all that concerns the discovery and conquest of the western hemisphere. Of all, however, that he has written, the pages containing the landing of Cortes in Yucatan, and the entrance of the Spaniards in the capital of Motezuma, appear to have been the most attractive to the general reader and the student; these pages being torn and soiled in the existing copies of his original Latin, as well as of its translation into foreign languages. We mention this circumstance, for it is not without a certain bearing upon our question. It proves how confidently the reading public has drawn upon the author’s statement, and how eagerly students have sought to digest his amazing accounts, quite unsuspicious, however, of the errors in dates as well as facts; admiring rather than criticizing the pompous phraseology of his mediæval Latin, or his often very suggestive but somewhat flighty speculations. In Petrus Martyr, therefore, we may recognize the originator of the widespread theory that the Mexicans possessed the secret of manufacturing bronze in the highest perfection and in accordance with metallurgical rules. We are, however, forewarned. The statement is of importance, and must be weighed before accepting it. We fear it will fail like many genial but unsupported inspirations, of which our author was susceptible. If we ask whence he derived the notion that the bronze tools were “argute temperata” we shall find that he failed to give any authority. Petrus Martyr, whom we often find quoting the full names and special circumstances by the aid of which he gathered the material for his historical letters, does not follow this laudable practice on this occasion, even though the matter was one of importance to investigators like himself. For these instruments of bronze, and many other tools sent over, must have been, in another way, still more interesting to him than the objects of industry themselves. These tools afforded the most palpable proof of an independent industry practised by that strange people beyond the sea; they were a key perhaps also to the riddle, how it was possible to perform those marvels of workmanship. This silence of Petrus Martyr respecting the details of the “_argutia_” which he professes that the natives employed in manufacturing their bronze is so much the more striking, since we find him enlarging a long while upon their manufacture of paper; and he shows himself correctly informed respecting that process. It is clear that the one was as well worth detailing as the other. Therefore we cannot help expressing the suspicion, that whilst he had correct information respecting the one, he had none respecting the other.