Looked at through a magnifying glass, these differences are of course much more easily discernible, and as they are of precisely the same kind that are found in the letters in the solid xylographic blocks, the conviction finally forces itself upon the mind, that such types could not have been cast, but must have been cut, and cut in wood. In an examination of this nature, the letters of a single page, or at the most those of the two pages of a single sheet, are all that can be attended to; for in their early efforts, the oldest printers usually printed but one small folio page, and seldom if ever more than two such pages at a time; and when as many copies as were wanted were struck off, the types were broken up for the next page, or two, and so on until the work in hand was completed. The types therefore that were used in the two pages first printed would constantly recur in all the following pages; and it is principally owing to this recurrence of particular letters bearing on their faces some special peculiarity, that the fact is detected that such ancient books as the _Speculum_ are printed with moveable letters. Mr. Ottley goes on:-- “_But let him_ (the person at all conversant with printing) _turn from the page which he has been examining, to one of those printed from a wooden block_; AND HE WILL SOON BE CONVINCED, _by the comparison, that the uniformity of appearance which he witnessed in the characters of the former, could not have been produced by means similar to those used in the execution of the latter_; for in the page printed from the engraved block he will discover, throughout, a sensible difference of form, as well as dimensions, between the various repetitions of the same letter: and in the capital letters especially, he will find this difference so material, as to render it easy for him to trace with a point the precise variations of form by which, for example, each of a dozen letters, S, is to be distinguished from all the others. It will then occur to him, _that it must have been a task of less difficulty to preserve uniformity in the shapes and dimensions of the letters, in a page of text engraved upon a plain block of wood_, which would have afforded the artist not only _the means of a constant comparison_, but also _a convenient and steady rest for his hand_ during the operation of engraving, _than it could have been to cut the numerous characters required_, with so strict a resemblance to each other, _on small separate pieces of wood or metal_; and he will perceive his second opinion to be untenable.”--(pp. 257-259.)