Description

HENRION, Denis (or Didier). Usage du compas du proportion. Paris: Michel Daniel, 1618.

First edition, extremely rare, of Henrion’s treatise on the proportional compass, the work that introduced the instrument to France. The proportional compass, also known as the sector, geometric compass, or military compass, was an analogue calculating instrument used widely from the late 16th century until modern times. Its origins are uncertain, but it was first described in print by Thomas Hood in 1598, and developed at about the same time by Galileo, although his description of it did not appear until 1606 (and then without any illustration).

“Henrion had seen a sector, made by Jacques Alleaume, in Paris. Seven years later, in 1623, Edmund Gunter published his work on the sector with no attribution of its invention to others. Henrion assumed that Alleaume had invented the sector and claimed any improvements as his own. It is obvious that Henrion was not aware of the earlier publications of Hood, Galileo, and several others. He goes on to claim that an unnamed individual (Gunter) had stolen the idea for the sector from him. In this work, Henrion describes a very simple sector made in 1616 by Daniel Chorez [illustrated on the double-page plate], a major French instrument maker of the day. This sector had only four scales (lines of lines, chords, planes and solids) . . . This work, like Gunter’s in England, was the one that introduced the sector into France. It was well received and went through at least twenty different editions” (Tomash & Williams).

As Henrion noted in the preface to the present work, he had hoped that Alleaume himself would write an explanation of the construction and use of the proportional compass, but his burdensome duties had prevented him from doing so; therefore Henrion himself had attempted to fill the gap. It has been asserted (e.g., by MacTutor) that ‘Denis Henrion’, and ‘Pierre Hérigone’, were in fact both pseudonyms of the Baron Clément Cyriaque de Magnin (1580-1643), but DSB gives separate entries to Henrion and Hérigone.

Goldsmith H246; Tomash and Williams H109 (this copy); OCLC lists, in US, Illinois, Michigan, and Brigham Young only. RBH list only one other copy since 1946.

8vo (166 x 102 mm), pp. [viii], 90, [6], with two engraved plates of the proportional compass and several woodcut illustrations in text (marginal waterstaining in upper margin, mostly light but heavier at the beginning, minute wormtrack in lower margin, nowhere near text). Contemporary vellum (soiled, and with portion of vellum lacking from fore-edge of upper cover). A genuine, unpressed copy in an unrestored contemporary binding.