^22 Mjj r-Gt'?ieraI Roy\ Account of the 



the farther extremity ; on the 22d of June, the tranfit inflrn- 

 raeiit was adjuiled over the thirteenth picket at Han worth 

 Summer-houfe, while direcled upon the flag-ftaff". But it being 

 now found, that the vertical plane pafiing through the flag-ftaff" 

 fell to the eaftward of the center of Banded ^pire, therefore 

 the tranfit was gradually moved to the eaftward, until by 

 repeated trials the three points were perceived to 'be in the fame 

 vertical plane, when the picket was moved, and re-placed 

 exactly under the axis of the telefcope, a few inches from its 

 lirft poiition. The fame operation w^^s repeated at the twenty- 

 iixth ftation, on the. farther hank of the Staines Road ; and,, 

 laftly, at the forty- fixth, forming the north- weft extremity, of 

 the bafe ; where a pit was immediately dug for the wheel, 

 whicii was placed therein, without however tilling in the earth 

 for the prefent,, that being deferred till near the completion 

 of the meafurement with the deal rods. Thus the two extre- 

 mities, and two intermediate points of the bafe, being accu- 

 iMtely placed, by the help of the tranfit inftrument, in the 

 lame vertical plane with Banfted Spire, it was eafily feen, that 

 by arranging camp colours in the intervals at any time, all the. 

 other points might be brought fo nearly to coincide with thele, 

 firft, as not to occafion, by deviation, any fenfible error in the. 

 meafurement afterwards to=bemade. This .application of tlie 

 tranfit fttewed us, however, that fome labour had been loft by 

 not ufing it fooner : for at the Staines Road, the tra61: cleared' 

 by the foldiers deviated about two feet and a half too much to 

 the weftward for the true line; and at King's Arbour it was. 

 twice as much ; fo that we were now obliged to widen the 

 cleared tra8:, by adding to the eaftern fide of It. 



On the fame day that the chief points in the bafe were jfixed^ 

 by means of the tranfit, aud the levels of the third fe£lion, 



taken 



