[18] Some writers consider that the whole of the text of what are considered the first and last editions, and a large portion of the text of the other two, were printed from moveable wooden letters; others again assert, that these letters were made of cast fusile metal. No positive proof, however, has been, or can be given that they were the latter. That the texts were separately printed, is evident, from the different inks employed, the burnished appearance of the paper at the back of the cuts, and the indentations at the back of the lines of type. These last, differing considerably in different specimens, give rise to differences of opinion as to whether the impressions were produced by an ordinary printing press, or by some other method of imparting pressure. The presumption is that all, or nearly all, the impressions of the oldest specimens of the art, printed only on one side of the paper or vellum, were taken in the Chinese way. Before the press was invented, there certainly was a _possibility_, but that was all, of printing otherwise; but after its invention, impressions could most easily be taken on both sides of the paper, without the risk of spoiling the first, while ‘perfecting’ (i. e. printing) the reverse or blank side of the sheet. As the press was not an essential in block-printing, it was probably not thought of in that embryonic state of the art. But after separable, and especially metallic, letters were made, the press could no longer be dispensed with; types would be all but useless without it; for although impressions might still be taken by careful rubbing, the paper being sufficiently damped, that process would be attended with much additional trouble, owing to the precautions rendered necessary to avoid cutting through the paper, or otherwise spoiling it by blacking the margins on the inked coffin or chase in which the types, when formed into a page, were screwed or quoined or wedged together. The date of the invention of the LETTER press, by the adaptation of the screw to the purposes of book-printing, is thus an important element in the consideration of questions relating to the origin of Typography. [19] About £1000, or £1200, of current English money. [20] Paper with the same water-mark was also used by the First Printer in England. _Vide_ Plate IX in vol. ii. of _The Life and Typography of William Caxton_. [21] Letter in _Builder_, Nov. 26, 1870. [22] So called after Andrea Mantegna, a celebrated Italian painter and engraver, born in Padua 1431, died 1505. Cards designed and coloured by this artist are very highly prized. [23] _Builder_, Nov. 19, 1870.