Himazcayva Mounrarms, 239 
base, served as a kind of exercise, to instruct us fully in the nature of what 
was to be done, and enabled me to:determine precisely the method, in which 
{ was to carry on the operation. -As it has been rejected, there is no occa- 
tion to give the‘ details, but I thought proper to notice the circumstance, 
to shew that when the line finally chosen, was actually commenced upon, 
we had acquired some degree of practice as well as confidence. 
19. Bzrore entering upon the details of the measurement, I may 
briefly notice the order in which the several parts of the operation were per- 
formed. A cross of clean fir 3} feet in height, was first set up at the dis- 
tance of 500 feet, being placed on the picket, in advance, forming a point: 
in the alignment of the base. The stands were then ranged as near as 
the eye could judge, in the direction of it, and their distances regu- 
lated by a rod of the proper length: by means of a small stick of fir, with a 
cross vane, held by one of the people in the fork of the stand ; three of them 
(that is the two outer and middle one); were brought correctly into the 
alignment, with a boning telescope resting on the preceding pair of rods. 
The small stick carrying the vane, bemg made to cover the cross, resting 
‘on the picket, by moving the stand to right or left as might be required. 
The forked stems were at the same time regulated, as to height, by bring- 
ing the cross vane, to cover the transverse piece of the cross on the picket, 
which had been originally regulated to the height, at which, it was 
thought the hypothenuse could be best carried on. The telescope was 
‘mounted on a wooden bed, which gave it an elevation of about three 
‘inches, above the surface of the rod. The cross vane of the small 
stick used for adjusting the forks of the stands, was set to such a 
YOL. XIv. 3 4h 
