The operation of presswork begins with inking the form on the bed of the press, which, in this illustration, is supposed to contain a form not unlike that of the _Speculum_, nested in a chase type-high. The sheet is laid on the tympan against guides that keep it in place. The frisket, containing the paper masks cut out to sink the irregularities of the form, is folded down in the line A B, partially covering the paper on the tympan. The tympan is then folded over on the line C D, which operation brings the paper down on the face of the form, ready to receive the impression. These are the appliances of a modern press. The frisket of the unknown printer was of much simpler construction, probably nothing more than a mask of paper laid on the form of types by hand.] [p308] XVI The Period in which the Speculum was Printed. The Paper-Marks of the Speculum, with Fac-similes . . . Not Evidence of Age . . . The Earliest Dated Annotation . . . Earliest Known Manuscript copy in Dutch . . . Indications that the Book was Printed at Utrecht . . . Probably Printed in the Last Half of the Fifteenth Century . . . Review of the Evidences . . . The Cambray Record . . . Printers of the Fraternity of St. John at Bruges . . . Testimony of Zell in the Cologne Chronicle . . . All Unsatisfactory . . . Discordant Opinions . . . Dutch Printing probably Xylographic . . . No Evidence of an Early Use of Types in Holland . . . Early Printing in Haarlem . . . Jacob Bellaert . . . Fac-simile of his Types . . . His Successors . . . Brito of Bruges, with Fac-simile of his Types . . . Was not an Inventor . . . Netherlandish Knowledge of Printing came from Cologne . . . Map of the Netherlands . . . Not probable that Types were Used there before 1463. * * * * * The utility and charm of historical researches do not depend upon the exactness of their results. Inasmuch as error is misfortune, so examination is profitable, even that which does no more than declare as evident the opinion which had been regarded as plausible. _Daunou._ * * * * * The paper-marks[165] of the _Speculum_ and of other works of the unknown printer have been repeatedly examined in the belief that they would reveal the place where and the time when the paper was manufactured. A Dutch author has said that these marks enable us to determine when the books in which they are to be seen were printed. An English author, [p309] who devoted the larger part of a folio volume to a review of the paper-marks of the block-books, undertook to prove from them that the _Speculum_ must have been printed before 1440. [Illustration] [Illustration] [Illustration] [Illustration]