202 ‘AN ACCOUNT OF THE - 
reversed in the YS:5 it then, ‘describes ‘a true vertical. This verifica- - 
tion ‘cannot be effected, except on calm nights. The circle was 
used by Lieutenant Hersert in taking all the angles of the small 
triangulation, and considering that it was then necessarily placed on a 
wooden tripod only, it performed well—at the great stations, Belville, the 
Chin“, Bairat and Surkunda, it had a firmer support. All the observa- 
tions, as well horizontal terrestrial angles, as of altitudes and Azimuths, were 
determined by us, both by the single and double elongations of the pole 
star, and at the principal station of Belville, with great care; and 1 trust 
with as much truth as it is possible to take them, with an instrument of 
moder ate dimensions. The altitudes of the peaks were observed at several 
places, and at different seasons, and the mean taken, except where a depres- 
sion had been observed. As the stations are far distant from each other, 
it is ; evident, that the elevations and depressions could not be taken at, or 
very near, ‘the same time, with the same instrument, but when they were 
observed, the circumstances of weather, were not very dissimilar, and it is 
hoped that the ratio of terrestrial refraction deduced, is sufficiently near 
the truth for answering the practical ends of the PUnNEY: As an instru- 
inent for taking zenith distances, the circle answers very well, when shel- 
tered from the weather, but on the exposed peaks of the grand stations, we 
eautd not avail ourselves, as we wished, of its powers. I lost much time at’ 
the Chit, mn trying to do $0, ‘put the winds by night, were 80 boisterous, that it 
was impossible to keep the adjustments perfect, and to use it in a tent, which 
is in continual danger of being blown away, distracts the attention; at the 
station of Belville in the plains, where I was more at my ease, I made toler- 
ably good observations for latitude, with the altitude circle, though not so 
