Wardington states of this work ‘this is a very important little atlas. Cassini came to Paris around 1670, and soon started work on the triangulation of France; this little volume is the first work (other than that devoted to the immediate area round Paris which was engraved by du Vivier) that was published’. Jean Dominique Cassini was an Italian astronomer and mathematician who after moving to France, was appointed by Louis XIV in 1669 as director of the Paris Observatory which was newly founded. He was made responsible for implementing the new astronomical methods of determining longitude. Along with Jean Picard and others he began a fresh survey of the French coasts which was completed by about 1681. It famously led to a comment from Louis XIV that his cartographers had lost him more territory than he had gained in all the wars. France it turned out was nowhere near as wide as had been previously thought. The project led to a survey of France by triangulation into which Cassini poured all his efforts. It was constantly delayed by political and practical problems until long after his death. In 1733 his son Jacques was instructed by Louis XV to finish the survey and by 1745 a preliminary map was available.

Wardington claimed that this was the first printing of the Cassini results and this was based on his dating of the atlas to c.1685. However we know that the atlas was most probably published in 1695. Firstly the ‘London Gazette’ for 11-15 July 1695 bore an advert from Morden, Thornton and Lea for this work and secondly it is more likely that the data would have been printed in France first. This is supported by the publication of ‘Le Neptune Francois’ in 1693, with the official support of the minister of finance. The first volume illustrated the Atlantic waters of France. This supports the argument even further as the numbered charts from 1-40 in the ‘Hydrographia Galliae’ are all on the ‘Atlantic’ coast. The two additional plates at the end are on the Mediterranean coastal ports. The ornate double page engraved title is the work of John Harris who is most likely also responsible for the charts. Wardington commented in his notes on his own example that he had ‘seen only one other copy … and that was however very incomplete.’ In the Wardington example two of the folding charts were imperfect, here all three are in very good condition. Provenance: ‘Jos. Huddart Dublin 1776’ inscribed first blank endpaper; French private collection 2005; English private collection. Refer Pastoureau (1984) Neptune Francois pp. 351-3; Phillips 2987; Shirley (2004) M.Mord 1a; Sotheby’s Wardington sale lot 102; Tyacke 279.