428 Major-General Roy’s Account of tie 
The meafuring rods, when put into the cheff in London, 
had been compared and found to agree with the ftandard. The 
comparifon was not repeated on the 1 6th ; but this being done 
on the 17th, at 7 h. A.M. under the oil-cloth canopy at the 
camp, they were found at a medium to exceed the ftandard by 
one- fiftieth of an inch, the temperature then being 62°* After 
the comparifon they were carried to the place of the tripod, 
when the operation was refumed by bringing, with the help of the 
plummet, the fame point of the rod with wdiich we had left off 
work, to coincide with the interfedlion on the brafs ruler. The 
meafurement of this day was clofed at the end of the tenth hypo- 
thenufe, when the rods being carried back to camp, were com- 
pared, and found accurately to agree with the ftandard. 
A confiderable fall in the barometer, between the evening of 
the 1 7th and the morning of the 19th, portended rain. Ne- 
ve rthelefs, all parties repaired to the place of rendezvous, 
which w r as appointed at the lower end of the bafe, in order to 
re-meafure the two firft hypothenufes, by placing all the rods 
in contaff, which on the 1 6th had been done partly one way 
and partly the other. The operation being according repeated 
with great care, the point of the frxtieth rod, which formerly 
correfponded to the center of the fecond picket, was now found 
to be puffed forward exactly forty-five inches, anfwerable 'to 
the deficiency on the fifteen Coincident rods, with which the 
menfuration was begun. It now began to rain, therefore the 
rods were carried back to camp, and being feverally compared, 
they were found to exceed the ftandard each by one-thirtieth of 
an inch, occafioned by the extraordinary humidity of the air. 
A heavy rain enfued ; and what made this much more regretted 
by all was, that in the forenoon their Majeflies gracioufly con- 
defcended to honour the camp with their pretence, and con- 
tinued 
