Measurement of a Eafe on Hounflow-Heath. 389 
th.ofe founded on a much longer bafe, and angles determined 
by a large circular indrumenf, being that propofed, as the 
bed: that could be made ule of in the operation now to be 
mentioned. 
In the beginning of O&ober, 1783, Comte d’Adhemas, 
the French Ambadador, tranfmitted to Mr. Fox, then one of 
his Majedy’s principal Secretaries of State, a Memoir of M. 
Cassini de Thury, in which he fets forth the great advan- 
tage that would accrue to adronomy, by carrying a feries of 
triangles from the neighbourhood of London to Dover, there 
to be connected with thofe already executed in France, by 
which combined operations the relative fituations of the two 
mod famous obfervatories in Europe, Greenwich and Paris, 
would be more accurately afeertained than they are at prefent 
This Memoir the Secretary of State, by his Majedy’s com- 
mand, tranfmitted to Sir Joseph Banks, the very refpe&able 
and worthy Prefident of the Royal Society ; who, about the 
middle of November, was pleafed to communicate it to me, 
propofng at the fame time, that I ffiould, on the part of the 
Society, charge myfelf with the execution of the operation 
To this propofition I readily adented, on being foon afterwards 
allured, through the proper official channels, that my under- 
taking it met with his Majedy’s mod gracious approbation. 
A generous and beneficent Monarch, whofe knowledge and 
love of the fciences are fufficiently evinced by the protection 
which he condantly affords them, and under whofe aufpices 
tney are feen daily to flourifh, foon fupplied the funds that 
were judged neceflary. What his Majedy has been pleafed to 
* M * Cassj ni 5 s Memoir, with the Aftronomer Royal’s remarks on what is 
therein alledged, concerning the uncertainty of the relative fituations of the two 
Obfervatories, will be given in the fequel. 
