3^0 Major -General Roy's Account of the 



give fo Hbcrally, it is our duty to manage with proper and be- 

 coming frugality, confiftent with the befl: poflible execution of 

 the bulinefs to be done, fo as to make it redound to the credit: 

 of the Nation in general, and of this Society in particular. 



The operation, whereof we are now to give fome account, 

 being the firfl of the kind, on any exteniive fcale, ever under- 

 taken in this country, naturally enough fub-dlvides itfelf into 

 two parts. Firft, the choice and meafurement of the baf^, with' 

 every poflible care and attention, as the foundation of th'd 

 work ; fecondly, the dlfpofition of the triangles, whereby ^d 

 bafe is to be connected with fuch parts of the coafl of this 

 iflandas are nearefl: to the coafl of France, and the determlna^ 

 tlon of their ang'les, by means of the befl inftrument that can be 

 obtained for the purpofe, from which the reiult or concluiioit 

 will be drawn. It is the firft part only, as a fubjeft of itfelf 

 fufficlently diflinil, that we are now to lay before the Society ; 

 it having been judged more advllable, to fhew that no time 

 has been loft in making reafonable progrefs, than to defer the 

 account till the whole operation fhould be ultimately com- 

 pleted. 



Choke of the Bafe. Tab. XVI. 



Hounfiow-Heath having always appeared to be one of the 

 moft eligible fituations, for any general purpofe of the fort 

 now under confideration, becaufe of its vicinity to the Capital 

 and Royal Obfervatory at Greenwich, its great extent, and the 

 extraordinary levelnefs of its furface, without any local ob- 

 ftrudions whatever to render the meafurement difficult ; be- 

 ing likewife commodioufly fituated for any future operations of 

 a fimilar nature, which his Majefty may pleafe to order to be 



extended 



