now measuring on the Continent. 179 



itself in passing with the fixed observatories of Geneva and 

 Milan, its eastern limit has already reached Fiume, on the 

 shores of the Adriatic ; and, by the operations with which 

 the Austrian government has charged itself, and which are in 

 progress, it is designed to be still further extended to Orsowa, 

 a town of Transylvania, on the frontiers of Turkey. The 

 portion of the parallel comprised between the meridians of 

 Marennes and Fiume, is between fifteen and sixteen degrees l 

 between Marennes and Orsowa, twenty-three degrees and a 

 half The geodesical operations applied to the measurement 

 of this arc were commenced in Italy, Piedmont, and Savoy, in 

 1802, having for their object the formation of a topographical 

 map of those countries, corresponding to that of France by 

 Cassini ; the project of measuring so extensive an arc perpen- 

 dicular to the meridian, not having been then formed. Their 

 execution was confided to the officers of the French corps 

 des Ingenieurs-geographes, who by the year 1814 had 

 covered the greater part of Italy, Piedmont, and Istria, with a 

 triangulation, resting on abase of 9998 metres, measured near 

 the course of the Ticino, between Milan and the Lake Mag- 

 giore ; and had thereby connected Fiume on the Adriatic, 

 with Rivoli between Milan and the Alps. In 1811, the 

 project of extending the triangulation across France to the 

 Atlantic, and making it subservient, in conjunction with a 

 determination of the corresponding celestial arc, to the deduc- 

 tion of the figure of the earth, w^as discussed at the instance 

 of M. de Laplace, and adopted by the French government. 

 Accordingly, in 1811, 1812, and 1813, a suite of triangles 

 detaching itself from the great chain of the French meridian, 

 in the parallel of forty-five degrees, was carried to the frontiers 

 of France and Savoy; and in 1818, 1819, and 1821, similai* 

 operations connected the chain of the French meridian with 

 the shores of the Atlantic. Finally, in consequence of a com- 

 munication from M. de Laplace to the academy at Turin in 

 1820, the Piedmontese government appointed a commission, 

 composed of astronomers and officers of the Austrian and 

 Sardinian etat-major, who in 1821 and 1822 connected the 

 operations in France and Italy by a triangulation carried 

 across the Alps : thus uniting Marennes on the Atlantic with 



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