HENRION, Denis - Usage du compas de Proportion. Nouvelle Edition, reveue, corrigee, & augmentee d'une seconde partie - 1624

"Nouvelle" edition (see below), 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.

This edition, which is "augmentée d'une seconde partie", was published in the same year as the "second edition". They are however quite different: this one is a quarto and has a double-page plate and also a second part, neither of which appear in the "second edition", which is an octavo. The additional part is included in order to address both the practice and the theory of the sector. RBH lists only one other copy of this Nouvelle Edition.

It has been asserted 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.

Small 4to, pp. [ii], 86, with one folding engraved plate of the proportional compass and several woodcut illustrations in text, entirely uncut. Contemporary vellum (soiled, and with small portion of vellum lacking from spine, manuscript paper spine label). A genuine, unpressed copy in an unrestored contemporary binding.