What are known as the soda-pulp and the sulphite processes are examples of this. The latter and other acid processes were not successful until cement-lined digesters were invented to withstand their corroding action. But now it is only necessary to have a convenient forest of almost any kind of wood to justify the establishment of a paper mill. It was the scarcity of rags, especially of linen rags, that forced inventors to find other paper-producing materials. It would be impossible and uninteresting in a work of this character to enumerate the mechanical details constituting the improvements of the century in paper-making machinery of all kinds. Thousands of patents have been granted for such inventions. With one modern Fourdrinier machine, and a few beating engines, a small paper mill will now turn out daily as much paper as could be made by twelve mills a hundred years ago. In moulding pulp into articles of manufacture, satisfactory machines have been invented, not only for the mere forming them into shape, but for water-proofing and indurating the same. From the making of a ponderous paper car wheel to a lady’s delicate work basket, success has been attained. _Paper bag machines_, machines for making _paper boxes_, applying and staying corners of such boxes, for making _cell cases_ used in packing eggs and fruit, and for wrapping fruit; machines for affixing various forms of labels and addresses, are among the wonders of modern inventions relating to paper. It is wonderful how art and ingenuity united about thirty years ago to produce attractive _wall papers_. Previous to that time they were dull and conventional in appearance. Now beautiful designs are rolled out from machines. _Printing._--We have already seen how paper making and printing grew up together an indefinite number of centuries ago in the Far East. Both block printing and movable types were the production of the Chinese, with which on their little pages of many-coloured paper they printed myriads of volumes of their strange literature in stranger characters during centuries when Europeans were painfully inscribing their thoughts with the stylus and crude pens upon papyrus and the dried skins of animals.