Cadrans solaires

1744 · D4448 — France 1744. Hardcover. Very Good. Manuscript book on paper in French. c.1744. 8vo 166 x 106mm. 8 355pp. written in brown ink in a clear humanist script with some calligraphic aspects between framed pages in a single column of approximately 28 lines headings in Roman majuscules. With 89 full-page diagrams and technical illustrations of sundial construction and usage and other supporting images three are on plates and two of which are folding at rear. Contemporary mottled calf spine gilt in compartments labeled “Gnomonique” on gilt red morocco lettering piece marbled endpapers & edges; edges uniformly toned occasional stains; expertly rebacked preserving the original spine somewhat worn. Full contents listed on first 6 pages for this expertly executed and comprehensive compendium on the sundial. The objective of this manual is to enable the 18th century audience to understand the operating principle of sundials by describing the construction and manipulation of different forms of sundials including the planet-sundial moon-clock celestial houses-clock polar-clock ancient Babylonian and Jewish clocks as well as the construction of quadrants and astronomical tables. The sun’s position in the sky has always been an obvious means to keep track of time. The use of shadows of sticks cast by the sun were a natural means of indicating the time of day by the direction of the shadow and the time of year by its length. Although town squares began constructing clocks beginning somewhere in the 14th century sundials remained in the picture well into the 18th century. Mechanical clocks were expensive and could be found only in the most noble of homes. They were also more of a curiosity at first; most people still used their sundials or just estimated the time of day by the height of the sun in the sky. In 1777 when the French General Lafayette wanted to express his admiration for his ally and friend General George Washington during the American Revolution he chose a silver Explorer sundial as his gift. But by the close of the 18th century clocks and watches began to supersede sundials. They had one huge advantage- they worked all day long and were not dependent on weather. However they were also notoriously unreliable- telling time only approximately within an hour and needing to be reset frequently of course with the help of a sundial. Although the work of this study is anonymous an ownership entry at the foot of the title helps to date the work: “Hic est Thorridon Rectoris Laurentii Moussault 1744.” This wide-ranging study of the sundial appears at a time when the mechanical clock was on its way into popular fashion. A unique scholarly work that may well be one of the last close studies of such an ancient and important time-telling tool. <br/><br/> hardcover