41 8 MiJor-GenerdI "RoY^i Account of the 



being ftrained back fo as to coincide with the point of com- 

 mencement, a ileel arrow was placed as ere6l as poffible in the 

 fenn-circular cavity of the brafs handle at the other end. The 

 chain being then drawn on, till the cavity in the rear handle 

 could be apphed to the firft arrow, a fecond was then placed in 

 that of the front handle, and fo on until lix chain lengths were 

 thus meaiuredoff; which terminating the firft hypotheniife, a 

 beech picket, fomething more than an inch fquare, and about 

 feven in length, with N^ I. cut upon it, was driven into the 

 ground, till its head was nearly level with the furface. It is 

 however to be remarked, that the fixth arrow of each hvpo- 

 thenufe was conftantly left in the ground till the firft of the 

 fucceeding one was placed, to avoid the error that would have 

 otherwife arifen in applying the rear end of the chain to the 

 picket inftead of the arrow. 



In this manner we proceeded on the i6th of June, and in 

 the fpace of about three hours and a half, completed the f ril 

 meafurement of the fouth-eafl: fedion of the bafe, comprehend- 

 ing the thirteen hypothenufes between the flag ftaff and ftation 

 nearHanworth Summer-houfe, the diftance being 78 chains or 

 78.00 feet, making 2600 yards ; and the mean temperature of 

 the air being 6'^''» 



On the fubfequent day this fefllon was re-meafured with.. 

 equal care, when the total extent fell ihort of the thirteenth 

 picket only five inches. And here it is to be obferved, that a 

 confiderable part of this difference prcbably arofe from the 

 ftretching of the chain acrofs Wolfey River, at the fame time 

 that the irregularities of the ground are greater in this thaa 

 in either of the other two fedions. The mean heat of this 

 day was 65°. 



The 



