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 011 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 Wroth am 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 
