Hurt tava Mountains. 249 
of the 2.3 rod, as limited by the mavk,. before noticed 300-966 inches. 
Comparator 1203. 
- $l. ° Te remaining two sods were now compared with these, for 
_ which purpose they were all four placed together, 1.2 and 2.3, being on 
the outside of the other two. Two arcs were described with a radius of 
43 imches from centres im the prolongation of the line of the divisions, | 
parallel to the axis of the outer rods. Both arcs sprang from the same 
points on 2.3, 1. e. the line marking the limit of 300-966 inches; Com- 
parator 4203: wath the several measures,’ accurately determined, were 
calculated the places where a line perpendicular to the axis of the 2.3 
reds, and drawn through this point, would ‘cut them. The distance of 
this imaginary line from certain points on the ivory scales of the rods, 
was also found. This line cut No. 1.2 at the division, 15°60 
Add. languette, "564 
16-164 
Now the mark of the 303 was, .occoccscoee 16°109 
Excess above 301 MACHES ys vitetarst e arsie steers 7035 = 014 in, 
Comparator being 1203.. 
; Bur it has been seen, that this line limited om 2.3 the 300-966 inches. 
) Comparator 12032 OarT. 2 ee eevee cds S01-O14 
Difference; 048 
Tne error, occasioned by the want of parallelism of the rods. This 
requires an equation for the intermediate rods, and it is easily found, being 
