At the same time Louis XIV., urged by Colbert, gave orders for the preparation of a map of France. Men of science undertook voyages from 1679 to 1682, and by astronomical observations found the position of the coasts on the Ocean and Mediterranean. But even these undertakings, Picard's computation of the Meridional arc, the calculations which determined the latitude and longitude of certain large cities in France, and a map which gave the environs of Paris in detail with geometrical exactitude, were still insufficient data for a map of France. As in the measurement of the Meridional arc, the only course to adopt was to cover the whole extent of the country with a network of triangles. Such was the basis of the large map of France which justly bears the name of Cassini. The result of the earlier observations of Cassini and La Hire was to restrict France within much narrower limits than had hitherto been assigned to her. Desborough Cooley in his "History of Voyages," says, "They deprived her (France) of several degrees of longitude in the length of her western coast, from Brittany to the Bay of Biscay. And in the same way retrenched about half a degree from Languedoc and La Provence." These alterations gave rise to a "bon-mot." Louis the XIV., in complimenting the Academicians upon their return, remarked, "I am sorry to see, gentlemen, that your journey has cost me a good part of my kingdom!" So far, however, cartographers had ignored the corrections made by astronomers. In the middle of the seventeenth century, Peiresc and Gassendi had corrected upon the maps of the Mediterranean a difference of "five hundred" miles of distance between Marseilles and Alexandria. This important rectification was set aside as non-existent until the hydrographer, Jean Matthieu de Chazelles, who had assisted Cassini in his labours, was sent to the Levant to draw up a coast-chart for the Mediterranean.