By attaching a cast of the hand-set type to cylinders it was possible to take advantage of the introduction of steam power with considerable economy of time entailed in running off the printed sheet; but it was impossible to reap the harvest of this economy while it was still necessary to set type by manual extraction from a box of each die for a letter, cypher or punctuation mark. Also, the manufacturer of paper from rag was a relatively costly process by modern standards; and the discovery of a cheaper source of raw material was a precondition of expanding trade in the printed word. Rag, be it said, is simply woven fibre of cotton or flax; and any vegetable fibre is good enough for the work of the wasp. It was therefore a great advance, when it was possible to use the by-products of the lumber camps for paper manufacture. Wood pulp as a source of paper came into its own in the eighties, though its use goes back to a German patent about 1840. In 1857 Routledge had introduced, as an alternative source of raw material, esparto grass from Spain and North Africa; and there had been notable advances in the mechanics of paper production during the preceding fifty years.
In 1803 the French printer Didot brought into England a device which took advantage of steam power by running wet pulp on to a moving, endless belt of wire mesh through which the water drained off. It could run off in a day six miles of paper of uniform width. In 1821 Crompton invented the process of drying by steam-heated rollers. Between 1803 and 1815 König in Germany and Cowper in Britain had perfected power-driven machinery for printing off a continuous roll of paper from cylinders carrying the type cast. The four-cylinder machine patented by Cowper and Applegarth in 1827 ran off 5,000 sheets per hour of the London _Times_ simultaneously printed on both sides. The Walter Rotary of 1866 appears to have been the first cylinder machine to print on both sides of an unwinding roll of paper with a power-driven mechanism to cut the sheets, previously fed to the machine by hand. By that time a cheaper source of paper was available.
The advent of cheap paper accommodated the purchase of reading matter to the purse of the poorer classes in the community; but it did not bring into their lives a daily stimulus to read. While type-setting remained a manual operation, the maintenance of a daily press was beset by many difficulties and possible only because it did not as yet aspire to the topical immediacy which could coax a large semi-literate section of the population into the habit of daily reading. What made possible a truly popular press was an invention thus described by McMurtrie: