Description des Machines et Procédés spécifiés dans les Description des machines et procédés spécifiés dans les brevets d’invention, de perfectionnement et d’importation, dont la durée est expirée was the official printed record of the patents granted in France that were issued under the 1791 patent laws. These patents were not printed until after their expiration date of either 5, 10 or 15 years from when they were issued.

From 1791 until 1844 it was incredibly expensive to get a patent issued. The patent tax for 5 years was 300 francs, for 10 years it was 800 francs and for 15 years it was 1500 francs. At the time the average worker’s daily wage was 1.5 francs.

This feels like a very high quality book with thick linen rag pages, gilded pages and marbled inside covers. It even came with a bookmark!

But the content inside the document is what is really important. This is the official record of what the Conservatoire royal des arts et métiers (i.e. the patent office) believed the patent was about, looking back after it expired. This document is not always a full transcription of the patentee’s original document but rather detailed abstract that specifically describes the patent and heavily focuses on describing the drawings that accompanied it. It does quote specific sections sometimes though, Additionally, all of the drawing in the original patent may not always be reprinted here.