in order to af certain the height of Mountains. 523 
I have thus, in a manner rather prolix, given a detail 
of the methods ufed to afcertain the quantity of the dif- 
ferent angles. It may he of ufe on a like occafion, and 
will at leaft ferve to determine within what limits the er- 
ror of the final refult may be expected to lye, as on the 
precifion of the geometrical operations all the compa- 
nions of the barometrical ones depend. This procefs 
once mentioned will exempt me and the reader from the 
trouble a fecond time, when he is informed, that the 
fame fidelity and pains were employed (where the cir- 
cumftances would admit) in all the trigonometrical ob- 
fervations, of which the annexed chart is a fummary. I 
proceed now to the determination of the fides, the com- 
putations of which are too well known to enter into this 
paper. 
Feet. 
Side ab 2760.8 
AC 15286.4 
BC 1404I.7 
Thefe with the angles give for the height of c above A, — 
The height of c above b, — — • — ~ 
The height of B above a, * — — « 
Thefe two added give the height of c above deduced from the 
obfervation at b, — ■ — — - 
But the height by aft ual obfervation at a was, — — 
Then the mean of the two, — — 
which is probably within three or four feet of the truth, 
or about one foot in a thoufand. 
Y y y 2 
Feet. 
2835.07 
2806.27 
22.18 
2828.45 
2835.07 
2831.76 
Having 
