,5^iV' now measuring on the Continent. 19l! 



that capital. At Strasbourg, it enters the territory of Baden, 

 which it crosses to that of Wirtemburg ; and successively the 

 territories of Wirtemburg and Bavaria, to those of Austria ; 

 connecting itself in its progress with the observatory of Mu- 

 nich. Proceeding onwards through Austria, it is successively 

 connected with the observatories of Vienna and Buda, and is 

 carried across all the countries subject to the Austrian domi- 

 nion, until it reaches the frontiers of Russia, between Mol- 

 davia and Gallicia, where its eastern limit is for the present 

 detei-mined by the meridian of Czernowitz. The extent of 

 the arc comprised between Brest and Czernowitz is not less 

 than 30 degrees, being a twelfth part of the entire parallel. 

 Its importance, therefore, is at the least not inferior to that of 

 the arc of the mean parallel of which the amplitude does 

 not attain 24 degrees. Nor are the operations less advanced ; 

 but as the accounts of them that have hitherto appeared are 

 far less systematic, or complete in the details, than those of the 

 mean parallel, we have been under the necessity of giving it 

 the second place in the present notice. For the particulars 

 with which we are acquainted, we are principally indebted to 

 two Memoirs, printed in the eighth volume of the Memorial 

 Topographique et Militaire, by Colonel Bonne, of the Inge- 

 nieurs-g^ographes, the survivor of the superior officers of that 

 corps intrusted with the conduct of the operations in France 

 and Bavaria; and to the correspondence of M. Littrow of 

 Vienna, with the Baron de Zach, published in the third cahier 

 of the third number of the Correspondance Astronomique, 

 &c., for 1822. 



When, in 1809, the Austrian government acceded to the 

 proposition of France^ the geodesical operations which the 

 measurement of the portion of the arc passing through Austria 

 would require were already far advanced ; having been under- 

 taken in reference to the topographical map of the Austrian 

 dominions. In France they were immediately commenced, 

 and their execution between Brest and Strasbourg was com- 

 pleted in 1823, forming a suite of upwards of 60 triangles, 

 resting on bases, measured near Paris for the centre, and near 

 Brest and Manheim for the extremities of the arc passing 

 through France. At the same period also the connexion 



