production of his earlier years, however equal and beautiful they appear in regard to their style; inasmuch as in his paintings we are enabled to detect little difference between his history of S. Cristoforo, painted in the flower of youth, and his altar-piece at S. Andrea of Mantua, which is considered one of his last labours. A specimen of his engraving with a date, is believed, however, by some, to be contained in a book of Pietro d'Abano; intitled "Tractatus de Venenis," published in Mantua, 1472, "in cujus paginâ prima littera initialis aeri incisa exhibetur, quæ integram columnæ latitudinem occupat. Patet hinc artem chalcographicam jam anno 1472 extitisse." Thus far writes the learned Panzer,[121] but whether he ever saw the work that exists in folio, and of seven pages, I am not certain.[122] A quarto edition was likewise edited in Mantua, 1473, and a copy is there preserved in the public library, but without any plates. It is certain, however, that about this period copper engraving was practised, not only in Mantua, where Mantegna resided, but also in Bologna. The geography of Ptolemy, printed in Bologna by Domenico de Lapis, with the apparently incorrect date of 1462, is in the possession of the Corsini at Rome, and of the Foscarini at Venice.[123] It contains twenty-six geographical tables, engraved very coarsely, yet so greatly admired by the printer, that he applauds this new discovery, and compares it to the invention of printing, which not long before had appeared in Germany. We give his words as they are quoted from the Latin without being refuted, by Meerman, at p. 251: "Accedit mirifica imprimendi tales tabulas ratio, cujus inventoris laus nihil illorum laude inferior, qui primi litterarum imprimendarum artem pepererunt, in admirationem sui studiosissimum quemque facillime convertere potest." The same writer, however, along with other learned men, contends that the date ought to be corrected, chiefly on the authority of the catalogue of the correctors of the work, among whom we find Filippo Beroaldo, who, in 1462, was no more than nine years of age. Hence Meerman infers, that we ought to read 1482; Audifredi and others, 1491; neither of which opinions I can agree with. For the work of Ptolemy being published at Rome, accompanied by twenty-seven elegant charts in 1478, what presumption, or rather folly, in the publisher of the Bolognese edition, to think of applauding its beauty, after the appearance of one so incomparably superior! I am therefore compelled to refer the former to an earlier period than the last mentioned year. Besides, I ought to inform the reader, that the engraving of twenty-six geographical plates, full of lines, distances, and references, must have been a long and difficult task, particularly during the infancy of the art, sufficient to occupy several years; as we are certain that three or four were devoted to the same purpose at Rome by more modern engravers, far more expert.