for determining the difference of meridians, &c. 79 



Sabine, who, it had been arranged, should proceed to the 

 first observing station on the French side of the Channel, 

 there to observe, in conjunction with Colonel Bonne, the 

 signals made on the French coast, and those made at the 

 station of Mont Javoult ; which latter were to be observed 

 immediately from the observatory at Paris ; while, on the 

 other hand, it was agreed that M. le Lieutenant Largeteau, 

 of the French corps of geographical engineers, should attend 

 at Fairlight, on the part of the French commission, and 

 observe, conjointly with myself, the signals made at La 

 Canche, the post on the opposite coast (elevated about 600 

 feet above the sea, being nearly the level of Fairlight Down) 

 and also those to be fired from Wrotham Hill, which were 

 expected to be immediately visible from a scaffold, raised for 

 the purpose on the roof of the Royal Observatory of Green- 

 wich. By this arrangement, and by immediate subsequent 

 communication of the observations made at each station, it 

 was considered that the advantage of two independent lines 

 of connexion, a British and a French, would be secured 

 between the two extreme stations; i. e. the two national 

 observatories ; every possibility of future misunderstanding 

 obviated, and all inconvenience on either side, arising from 

 delay, or miscarriage in the transmission of observations, be 

 avoided. 



With the assistance of Capt. Sabine, and by the help of 

 exact information as to the azimuths of Wrotham and other 

 nearer stations in the triangulation of 1821, with which Capt. 

 Kater had obligingly furnished us, and of which Fairlight 

 Church proved the most convenient, being close at hand and 

 favorably situated, and easily visible in the twilight ; and 



