Boussuge, Emmanuel <br/><br/>
The description of the arts in the Encyclopédie: The slate quarries 

 -  2020.<br/>							 
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<br/><br/> The treatment of slate quarries in the Encyclopédie was originally organised by Diderot following the proofs of the illustrations in the Description des arts et métiers and the ‘explanations’ he had acquired in 1749. After the Patte affair (1759-1760), the domain was extensively reorganised, and the letterpress volumes in which the technical language was used were abandoned in favour of the engravings, which became the main object of the encyclopedists’ attention. To enrich and profoundly renovate the work’s approach, Diderot could count on the unknown draughtsman ‘de la Croix/Delacroix’ and on the civil engineers Jean Beddevole alias ‘Jean de Voglie’, Perronet and Viallet. The role of each of them is here clearly delineated and many details are provided about their biographies and participation in the Encyclopédie. The case study of slate quarries provides a methodological key allowing us to follow a fascinating aspect of the adventure of the Encyclopédie. The development concerning ‘technical language’ is an original contribution about a little-known facet. Thanks to the method used here, many articles can now be attributed and a precise chronology established. This article also includes five documentary appendixes.