Nouvelles Methode pour Divisier les Instruments de Mathematiques et d'Astronomie

[Paris]: Arts et Metiers, 1768. First Edition.. Later 19th century bds.. Very good; tide marks to corner of the last two plates; some dustiness; untrimmed. Folio, [2], [1] - 44 pp. + 15 highly detailed copper engraved plates.

This is a description of a ruling engine that would permit the consistent and accurate division of arcs. The duc de Chaulnes was constantly working on the development of this device throughout the 1760s. By 1768 he had perfected the first ruling engine (5 yrs. prior to Ramsden). The innovation of his design was the elimination of the part played by a skilled craftsman. By mechanical means de Chaulnes was able to produce consistent precise results. The book offered here includes the detailed plates of the device and also incorporates the design for his microscope to read the divisional increments. A major chapter in the history of the construction of accurate astronomical instruments. The work was originally part of the Description des Arts et Metiers, v. 13. See Daumas for illustrations and a lengthy entry.