CHAPTER IX 



THE REFORMATION OF CARTOGRAPHY 



IN FRANCE 



In the seventeenth century, the desire to test new hypotheses 

 of the physical universe stimulated attempts to determine 

 accurately the dimensions and figure of the earth, and these 

 then became possible through the invention of more precise 

 instruments to make the necessary observations. These in- 

 cluded the telescope, the pendulum clock, and tables of 

 logarithms. The measurement of an arc on the earth's surface 

 was the first step, and this, though primarily a geodetic opera- 

 tion, contributed eventually to the advance of cartography. 



The first attempt of any value to determine the length of 

 a degree in this way had been made by Snellius in Holland 

 in 1615, but the operation was first carried out with an approach 

 to accuracy in France, where in the latter half of the seventeenth 

 century there was notable scientific activity under the patron- 

 age of the 'Roi soleii', Louis XIV, and the 'Academic royale 

 des sciences' founded in 1666. In that country, one of the first 

 highly centralized national states in Europe, there was a 

 growing demand for maps and charts, and a realization that 

 they could only be based satisfactorily on a precise scientific 

 framework. Maps were required not only for military purposes, 

 but for the proper organization of the extensive road system, 

 the development of internal resources, which was the aim of 

 men like Colbert, and the general promotion of commerce 

 at home and abroad. 



The successive stages in the making of the new map of 

 France were (1) the measurement of an arc of the meridian 

 of Paris by the Abbe Picard, 1669-70, by means of a chain of 

 triangles; (2) the extension of the meridian until in 1718 it ran 

 from the Pyrenees to Dunkirk; (3) the first attempts to produce 

 a new map of France by adjusting existing surveys, supple- 

 mented by observations for latitude and longitude, to the Paris 



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