Page:On the economy of machinery and manufactures - Babbage - 1846.djvu/146

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(159.) This enumeration, which is far from complete, of the arts in which copying is the foundation, may be terminated with an example which has long been under the eye of the reader; although few, perhaps, are aware of the number of repeated copyings of which these very pages are the subject.

1. They are copies, by printing, from stereotype plates.

2. These stereotype plates are copied, by the art of casting, from moulds formed of plaster of Paris.