The principle of producing impressions by means of a cylinder, and of inking the types by means of a roller, was not new. We have seen, in the preceding memoir, that as early as 1790 William Nicholson had patented such a method, but his scheme had never been brought into practical operation. Mr. Walter endeavoured to enlist Marc Isambard Brunel--one of the cleverest inventors of the day--in his proposed method of rapid printing by machinery; but after labouring over a variety of plans for a considerable time, Brunel finally gave up the printing machine, unable to make anything of it. Mr. Walter next tried Thomas Martyn, an ingenious young compositor, who had a scheme for a self-acting machine for working the printing press. He was supplied with the necessary funds to enable him to prosecute his idea; but Mr. Walter's father was opposed to the scheme, and when the funds became exhausted, this scheme also fell to the ground. As years passed on, and the circulation of the paper increased, the necessity for some more expeditious method of printing became still more urgent. Although Mr. Walter had declined to enter into an arrangement with Bensley in 1809, before Koenig had completed his invention of printing by cylinders, it was different five years later, when Koenig's printing machine was actually at work. In the preceding memoir, the circumstances connected with the adoption of the invention by Mr. Walter are fully related; as well as the announcement made in The Times on the 29th of November, 1814--the day on which the first newspaper printed by steam was given to the world. But Koenig's printing machine was but the beginning of a great new branch of industry. After he had left this country in disgust, it remained for others to perfect the invention; although the ingenious German was entitled to the greatest credit for having made the first satisfactory beginning. Great inventions are not brought forth at a heat. They are begun by one man, improved by another, and perfected by a whole host of mechanical inventors. Numerous patents were taken out for the mechanical improvement of printing. Donkin and Bacon contrived a machine in 1813, in which the types were placed on a revolving prism. One of them was made for the University of Cambridge, but it was found too complicated; the inking was defective; and the project was abandoned. In 1816, Mr. Cowper obtained a patent (No.3974) entitled, "A Method of Printing Paper for Paper Hangings, and Other Purposes."