In the first number of Blackfriars I promised, with the permission of the Editor, to follow a paper upon “The Author’s Tool” with another on the effect of printing on Letters. We think that we know too well the extent of our debt to Caxton to reflect, as a rule, upon the remoter consequences of the invention of printing. The advantages of a multiplication of manuscripts are obvious. The disadvantages are also worth a moment’s thought. To begin with, the multiplication of anything leads us into the realm of arithmetic, a mystic science, not because certain numbers have a peculiar significance whereby we call three and seven “mystic numbers,” but because the mere multiplication of anything changes its character. For example, a fine house is a fine thing, but a row of similarly designed fine houses is detestable. In repetition itself there seems to be something ominous. This is a fact which everyone knows, and no one can explain. All we can say is that quantity and quality seem to be by nature hostile to each other. Perhaps the advantages and disadvantages of the invention of printing can be summarized fairly in the statement, that printing has made the best books more accessible and multiplied indefinitely the worse. But before we consider whether a general accessibility of the best books is free from disadvantage, and whether the multiplication of bad books is something gained, we must remember that the influence of numbers has been apparent, not only in the increase of books printed, but also in the increase of readers. Multiplication of population soon followed multiplication of books.