in order to cifc&rtain the height of Mountains. 5 2 t 
may be proved hereafter, would occaiion an error of 
only three feet in the diftance of the mountains, and 
feven inches in the height. I proceed next to the ver- 
tical angles. 
Determination of the inclination of the Jides ac, bc, and 
ab, with the horizon ; the height of the eye at the in- 
Jlrument being four feet above the ground. 
Altitude from below at a. 
o / /j 
Inclination of ac, — 10 33 2 
Corre&ien for the part of 
the fignal which was f — 1 38 
obferved, 9 
Correction for the line of | __ Q 
collimation, — i 59 
Correct for the refraCtion, — 027 
True Altitude of c from a, 10 29 58 
Deprefiion from above at 
o / /> 
IO 29 18 
CorreCt for the fignal, — +16 
— — for the line of col- \ 
limation, — J + 59 
— — for refraCtion, -f 27 
True deprefiion of a from c, 10 31 o 
Arch intercepted between, J 
or curvature. 
2 30 
True altitude of c from a*| 
deduced from the obfer- IO 28 30 
vation alt c, J 
Mean corrected altitude of c from a = io° 29' 14"^. 
{g) If the computation were to be made from either of the obfervations take® 
feparately, the difference would amount to only three feet in the height of c| 
and this may either be in the correction of the line of collimation, the effeCfc 
©f refraction, or in miftaking the part of the fignal that was obferved : for, 
whilft I was gone to the top of the mountain, fome peafants pofTeffcd themfelves 
of the handkerchiefs I had fixed to the fignals below in order to haye a 
tonfpicuous and determined point. 
YU 
VOL. LXVII 
Incli- 
