An edition of Ptolemy in folio, with the maps engraved on copper, was printed at Bologna by Dominico de Lapis with the erroneous date M.CCCC.LXII. This date is certainly wrong, for no work from the press of this printer is known of an earlier date than 1477; and the editor of this edition, Philip Beroaldus the elder, was only born in 1450, if not in 1453. Supposing him to have been born in the former year, he would only be twelve years old in 1462. Raidel, who in 1737 published a dissertation on this edition, thinks that two numerals--XX--had accidentally been omitted, and that the date ought to be 1482. Breitkopf thinks that one X might be accidentally omitted in a date and pass uncorrected, but not two. He rather thinks that the compositor had placed an I instead of an L, and that the correct date ought to stand thus: M CCCC L XLI--1491. I am however of opinion that no instance of the Roman numerals, L XLI, being thus combined to express 91, can be produced. It seems most probable that the date 1482 assigned by Raidel is correct; although his opinion respecting the numerals--XX--being accidentally omitted may be wrong. It is extremely difficult to account for the erroneous dates of many books printed previous to 1500. Several of those dates may have been accidentally wrong set by the compositor, and overlooked by the corrector; but others are so obvious that it is likely they were designedly introduced. The bibliographer who should undertake to enquire what the printers’ reasons might be for falsifying the dates of their books, would be as likely to arrive at the truth, as he would be in an enquiry into the reason of their sometimes adding their name, and sometimes omitting it. The execution of the maps in the edition of De Lapis is much inferior to that of the maps begun by Sweinheim, and finished by Bukinck in 1478.