Mr.Koenig, in his account of the invention, says that "sheet M of Acton's 'Hortus Kewensis,' vol.v., will show the progress of improvement in the use of the invention.

Altogether, there are about 160,000 sheets now in the hands of the public, printed with this machine, which, with the aid of two hands, takes off 800 impressions in the hour"[4] Koenig took out a further patent on July 23rd, 1813, and a fourth (the last) on the 14th of March, 1814.

The contrivance of these various arrangements cost the inventor many anxious days and nights of study and labour.

But he saw before him only the end he wished to compass, and thought but little of himself and his toils.

It may be mentioned that the principal feature of the invention was the printing cylinder in the centre of the machine, by which the impression was taken from the types, instead of by flat plates as in the first arrangement.