42 4 M^'jor -General Roy's Account of the 



chain, if the furface had been one uniform incrined plane 

 throughout its whole extent. But, although the alcent of 

 Hounflovv-Heath is fo fmall, and fo gradual, as to occaiioii 

 little more than half an inch of redudl:ion, from the 46 hypo- 

 thenufal to the 46 bafe diftanccs, into which it is divided, as 

 maj be feen by referring to the table; yet each of thefe hy- 

 pothenufes containing again many other Imall irregularities, all 

 of which affe6l the meafurement by the chain, in proportion to- 

 their number and height, in every fpace of 600 teet, their' 

 united effe£ls, including the lateral deviations from the true 

 line in meafurlng, do fomewhat more than compenfate for the 

 extra-length of the chain, as will be feen hereafter in com- 

 paring the length of the bafe juft now obtained with that: 

 given by the rods. 



The weather, which during the greater part of June had-" 

 been wet, became ftiil worfe towards the end of the month 

 and firft week of July % fo much fo, that even if the deal rods- 

 had been ready they could not have been ufed with 'advantage.. 

 The foldiers, neverthelefs, were not idle, being, when the- 

 weather would permit, partly employed in clearing; the Heath,, 

 and partly in affifling Mr» Reynolds in the furvey, towards-, 

 the perfecting of which many chief points were fixed by 

 means of my aftronomical quadrant, placed for that ptrrpofe at* 

 feveral different ftations of the bafe. At this time too (July- 

 8th) I levelled from the lower end of the bafe to the furface of 

 the Thanaes at Hampton, and found the defcent to be 36.11 

 feet. 



Meafurement- 



