On the supposition that the types of the _Speculum_ really were of cast metal, Koning’s idea is much more reasonable than that of Ottley; but he is wrong in his notion that matrices could be struck in lead or pewter, from punches of hard wood on which letters of the size and character of those used in the _Speculum_ had been engraved. A few indifferent matrices might indeed be struck from some of the larger letters, say the letter =m=, but of the smaller ones, and those which had fine hair strokes, both capitals and minuscules, the fine strokes and faces of the letters would invariably be crushed. That, at any rate, is the result of a series of experiments made by the writer, with the view of ascertaining whether with letters so engraved on wood and with the softest procurable sheet lead, matrices could be struck from which types might be cast; and in which he was not successful in a single instance. Admitting, however, for the moment, that the printer of the _Speculum_ succeeded in striking a complete set of matrices; it has been proved by experiments, that from matrices of soft lead as many as from 120 to 150 letters can be cast,[120] before they are rendered useless; only after 50 or 60 had been made, the fine strokes would begin to thicken. Now it has already been shewn, that the oldest printers did not put to press more than a single page, or at most two pages, at a time, in their earliest attempts in the new art. This is a fact, acknowledged by every one who has made the Incunabula of the Fifteenth century a subject of special study. Admitting then that two pages of the _Speculum_ were printed together, what amount of type, and how many of each letter would be required for those two pages?