130 MAPS AND THEIR MAKERS 



veyors, including La Hire, known also for his projection, were 

 sent to survey the coasts. A map by La Hire, embodying the 

 results, was presented by him to the Academic in 1684, and 

 subsequently published as 'Carte de France corigee par 

 Ordre du Roi sur les Observaons de Mrs. de I'Academie des 

 Sciences', 1693. This showed both the older outline of the 

 coasts and the new, the general result being to shift the western 

 extremity of France one and a half degrees of longitude to the 

 east, in relation to the Paris meridian, and the southern coast- 

 line about half a degree of latitude to the north. The sight of 

 this map is said to have prompted Louis XIV to remark that 

 the survey had cost him more territory than a disastrous 

 campaign. 



The second Cassini, Jacques, realizing that any attempts to 

 fit haphazard surveys to the Paris meridian must be unsatis- 

 factory, became the advocate of the complete triangulation of 

 France, and with his son, Cesar Fran9ois Cassini de Thury, 

 was engaged from 1733 on this extension. The backbone of 

 the triangulation was the 'verified' meridian of Paris. Along 

 this at intervals of 60,000 toises (rather more than one degree 

 of latitude), perpendiculars were carried geometrically to the 

 east and west, from which the positions of towns and other 

 points of importance were fixed. This was the origin of the 

 projection now known by Cassini's name, in which the co- 

 ordinates of a point are given with reference to a central 

 meridian and the distance along the great circle through the 

 position which cuts the meridian at right angles. 



Progress was set out in 1744 on the 'Nouvelle carte qui 

 comprend les principaux triangles qui servent de fondement 

 a la description geometrique de la France'. Cassini de Thury 

 had succeeded in obtaining government support for the 

 proposed topographical map on this framework, and the work 

 was begun at the national expense in 1747. Nine years later, 

 however, this was withdrawn, owing to heavy military expendi- 

 ture. Cassini at once, without hesitation, took the bold step of 

 assuming entire responsibility for the survey. He received 

 authority to form an association to finance its completion, 

 obtained the necessary support, partly from various pro- 

 vincial States- General who appreciated the value of accurate 



