ASTRONOMERS AND CARTOGRAPHERS

"It was sufficiently clear," say the Memoirs of the Academy of Sciences, that the maps unduly extended the Continents of Europe, Africa, and America, and narrowed the Pacific Ocean between Asia and Europe. These errors had caused singular mistakes. During M. de Chaumont's voyage, when he went as Louis XIV.'s ambassador to Siam, the pilots, trusting to their charts, were mistaken in their calculations, and both in going and in returning went a good deal further than they imagined. In proceeding from the Cape of Good Hope to the island of Java they imagined themselves a long way from the Strait of Sunda, when in reality they were more than sixty leagues beyond it. And they were forced to put back for two days with a favourable wind to enter it. In the same way upon their return voyage from the Cape of Good Hope to France, they found themselves at the island of Flores, the most western of the Azores, when they conceived themselves to be at least a hundred and fifty leagues eastward of it. They were obliged to navigate for twelve days in an easterly direction in order to reach the French coast. As we have already said, the corrections made in the map of France were considerable. It was recognized that Perpignan and Collioures more especially were far more to the east than had been supposed. To gain a fair idea of the alteration, one has only to glance at the map of France published in the first part of the seventh volume of the memoirs of the Academy of Sciences. All the astronomical observations to which we have called attention are noted in it, and the original outline of the map, published by Sanson in 1679, makes the modification apparent.

 

Map of France

Map of France, corrected by order of the king, in accordance with the instructions of the Members of the Academy of Sciences. (Fac-simile of early engraving.)

Cassini was right in saying that cartography was no longer at its height as a science. In reality, Sanson had blindly followed the longitudes of Ptolemy, without taking any note of astronomical observations. His sons and grandsons had simply re-edited his maps as they were completed, and other geographers followed the same course.

William Delisle was the first to construct new maps, and to make use of modern discoveries. He arbitrarily rejected all that had been done before his time. His enthusiasm was so great that he had entirely carried out his project at the age of twenty-five. His brother, Joseph Nicolas, who taught astronomy in Russia, sent William materials for his maps. At the same time his younger brother, Delisle de la Ceyére, visited the coast of the Arctic Ocean, and astronomically fixed the position of the most important points. He embarked on board De Behring's vessel and died at Kamtchatka. That was the work of the three Delisles, but to William belongs the glory of having revolutionized geography.

"He succeeded," says Cooley, "in reconciling ancient and modern computations, and in collecting an immense mass of documents. Instead of limiting his corrections to any one quarter of the earth, he directed them to the entire globe. By this means he earned the right to be considered the founder of modern geography."

Peter the Great, on his way to Paris, paid a tribute to his merit by visiting him, and placing at his disposal all the information he himself possessed of the geography of Russia.

Could there be a more conclusive testimony to his worth than this from a stranger? and if French geographers are excelled in these days by those of Germany and England, is it not consolatory and encouraging to them to know, that they have excelled in a science, in which they are now struggling to regain their former superiority?

Delisle lived to witness the success of his pupil, J. B. d'Anville. If the latter is inferior to Adrian Valois in the matter of historical science, he deserved his high fame for the relative improvement of his outlines, and for the clear and artistic appearance of his maps.

"It is difficult," says M. E. Desjardins, in his "Geographie de la Gaule Romaine," "to understand the slight importance which has been attributed to his works as a geographer, mathematician, and draughtsman." The latter more especially do justice to his great merit. D'Anville was the first to construct a map by scientific methods, and that of itself is sufficient glory. In the department of historical geography, D'Anville exhibited unusual good sense in discussion, and a marvellous topographical instinct for identifications, but it is well to remember that he was neither a man of science, nor even well versed in classic authorities. His most beautiful work is his map of Italy, the dimensions of which, hitherto exaggerated, extended from the east to the west in accordance with the ideas of the ancients.

In 1735, Philip Buache, whose name as a geographer is justly celebrated, inaugurated a new method in his chart of the depths of the English Channel, by using contour levels to represent the variations of the soil.

Ten years later d'Après De Mannevillette published his "Neptune Oriental," in which he rectified the charts of the African, Chinese, and Indian coasts. He added to it a nautical guide, which was the more precious at this period, as it was the first of the kind. Up to the close of his life he amended his manual, which served as a guide for all French naval officers during the latter part of the eighteenth century.