Meafiirement of a Bafe on Hounflow-Heath. 417 



the third, we found ourfelves, on the i6th of June, in readi- 

 nefs to begin the rough meafurement. 



Lieut. Colonel Calderwood, of his Majefty's Horfe- 

 ■Guards, F.R.S. had, from the beginning, been fo good as 

 to promife his affiftance in the operation. Lieut. Colonel Pr in- 

 gle too, of the Corps of Engineers, obligingly became a 

 volunteer on the occafion ; as did alfo Mr. Lloyd, F.R.S. a 

 few days afterwards; while Enfign Reynolds, of the 34th 

 regiment, who had for fome time pafl been employed in fur- 

 veying the environs of the Heath, continued that work with 

 fuch fpare hands as could be afforded him for that purpofe ; 

 and it is to the plan (tab. XVI.) done by that officer, that it will 

 be necefTary to refer in any thing regarding locality, in what 

 has hitherto been faid, as well as in the fubfcquent relation. 



The lower end of the bafe had for fome time paft been dif- 

 tinguiflied by a St. George's flag fixed to the top of a fir fpar, 

 thirty-five feet in height; and one of the fignal bell-tents flili 

 remained at the flation near the fummer-houfe. A rope of 

 200 yards being made very faft by a flrong iron picket, driven 

 into the ground at the bottom of the flag-ftaff, the other end 

 was carried on along the bafe, and placed at the bottom of a 

 camp-colour, in a line with the bell-tent. The rope beuig 

 wound around a flrong iron reel, prepared for the purpofe, was 

 thereby ft retched extremely tight, a perfon occafionally lifting it 

 up in the middle, or at other places, and letting it drop again, fo 

 as to bring the whole into the fame ftraight line. Five perfbns 

 were neceffary for the proper management of the chain ; two 

 at each end for its adjuftment there, and one towards the mid- 

 dle, to lay it clofe to the rope, or to bear it up in any particu- 

 lar place, where the circumftances of the ground rendered 

 fuch precautions ufefuL The zero or rear end of the chain 



I i i 2 being 



