V. TRIGONOMETRIC MEASUREMENT OF HEIGHTS AND
DISTANCES.
I. Instruments : Theodolites, pocket sextants, and vertical circles.
II. Method op Operation.
III. Designation op the Objects measured.
IV. Values and Formula adopted.
V. Example.
I. INSTRUMENTS.
In the Himalaya and the elevated districts in the north which have been but
partially explored as yet, we frequently made use of theodolites for the determination
of heights, the determination of the latitude and longitude being at the same time
obtained.
We had five theodolites with us, two of which were divided into 20"; and the
other three into 30". A detailed description of these instruments has been given in
connection with our astronomical and magnetic observations.1
Pocket sextants, as well as vertical circles,2 were occasionally used for determining
small differences of level.
In the choice of localities for our operations, we took particular care to select
such places as not only allowed of a considerable part of the mountain chains being
surveyed at once, but also presented at the same time the opportunity of connecting
the results with our panoramas and drawings. As our observations were made during
the actual progress of our journeys, it was not possible to connect each single series
1 See Vol. I., pp. 73 to 76.
2 A description and a figure of this instrument is given in "Neue Untersucliungen iiber die Alpen, by H. and
A. S. 1854," p. 128.
II. !)
DISTANCES.
I. Instruments : Theodolites, pocket sextants, and vertical circles.
II. Method op Operation.
III. Designation op the Objects measured.
IV. Values and Formula adopted.
V. Example.
I. INSTRUMENTS.
In the Himalaya and the elevated districts in the north which have been but
partially explored as yet, we frequently made use of theodolites for the determination
of heights, the determination of the latitude and longitude being at the same time
obtained.
We had five theodolites with us, two of which were divided into 20"; and the
other three into 30". A detailed description of these instruments has been given in
connection with our astronomical and magnetic observations.1
Pocket sextants, as well as vertical circles,2 were occasionally used for determining
small differences of level.
In the choice of localities for our operations, we took particular care to select
such places as not only allowed of a considerable part of the mountain chains being
surveyed at once, but also presented at the same time the opportunity of connecting
the results with our panoramas and drawings. As our observations were made during
the actual progress of our journeys, it was not possible to connect each single series
1 See Vol. I., pp. 73 to 76.
2 A description and a figure of this instrument is given in "Neue Untersucliungen iiber die Alpen, by H. and
A. S. 1854," p. 128.
II. !)