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." The principal feature of this invention consisted in the curving or bending of stereotype plates for the purpose of being printed in that form.

A number of machines for printing in two colours, in exact register, was made for the Bank of England, and four millions of One Pound notes were printed before the Bank Directors determined to abolish their further issue.

The regular mode of producing stereotype plates, from plaster of Paris moulds, took so much time, that they could not then be used for newspaper printing.
Two years later, in 1818, Mr.Cowper invented and patented (No.

4194) his great improvements in printing.

It may be mentioned that he was then himself a printer, in partnership with Mr.Applegath, his brother-in-law.