962 AN ACCOUNT OF THE 
with the chain, as I am ignorant in what temperature it had been ad- 
justed, with the brass standard. And I think the difference of its length 
_ with different weights, (the maker having omitted to state with what 
weight it had been found to be exactly 100 feet) affords another, and a 
valid reason for adhering to the brass scale in preference. It is however 
satisfactory to’ observe that the difference of two determinations so entire 
ly independant of each other, does not amount to 1 foot on a distance of 
4 miles. 
44, Ir now only remains to give the several reductions of the base, 
and from the details to conclude the real length as reduced to the level of 
¥ $ ' i’y Go 
the sea, anda temperature of 62, 
Feet. Feet, 
Hirst 2174 sets of rods X 1000041 == 21,750:9 
Deducted over lapped, -.ssccceseconess 176 
21,733°3 
The sum of all the Comparators is, 460-920 
& 1141 217°332x2 = 495-950 
Difference, 35°030 
x93 . 
2 ! —— 1.4 
Inch. 
= 16°640 21,7319 
Sum of reductions byhorizontal,line, .....00. 26 
: | 21,7293 
Sum-of Sth columns. soc. l bss soe. : 2 
es 
Carried forward, ...cceo 21,729'1 
