DOI Seite / Zitierlink:
https://doi.org/10.11588/diglit.20131#0093
SECTION I.
METHODS OF OBSERVATION AND CALCULATION.
I. Instruments: a. Theodolites; b. Chronometers; c. Meteorological Instruments.—Mode of packing.
II. Introductory Calculations: a. Refraction; b. Parallax; c. Methods of Interpolation, Quantities depending on
the Yearly Motion, or on the Anomalies in the Orbit, and Quantities depending on the Daily Motion.
III. Methods tor calculating Latitude and Time: 1. Observations of Stars. 2. Observations of the Sun: Method 1.,
for unequal Altitudes; Method II., for corresponding Altitudes; Method III., for circum-meridian Altitudes.
3. Determination of the Meridian.
IV. Methods for calculating the Longitude: 1. Longitude by Chronometers. Rates of the Chronometers used:
a. Chronometer 3, 1854 to 1857; b. Chronometers 1 and 2, 1854 to 1856; c. Chronometer 1, 1856 and 1857;
cl. Chronometer 4; e. Resulting Table of Rates. 2. Longitude by Celestial Phenomena: a. Lunar Distances;
h. Eclipse of the Moon, October, 1856, with physical remarks.—Terrestrial signals.
V. Method of Equations of Condition: a. Application to Latitudes; b. Example for Latitude; c. Application to
Longitudes.
I. INBTKUMENTS.
a. THEODOLITES.
A he instruments for angular measurements which we used were the following:
Theodolite 1, Jones.1 It had a horizontal circle of 5, and a vertical circle of
4Vo inches diameter. The horizontal circle had three verniers, reading 30 seconds; the
two verniers of the vertical circle gave the minutes.3 There was also a tangential
screw, which allowed of repetitions being made. For surveying purposes, as well as
for an approximate determination of the declination, a magnet could be screwed
upon the telescope. The levels were large. and always remained in very good order.
1 Jones, 4, Rupert Street, London.
2 The mean of the verniers and the use of the repetition apparatus allowed of 10 seconds being estimated with
sufficient accuracy. In some cases, even 5 seconds or less were noted, being then the mean of several readings.
This remark also applies to our other theodolites.
I. 10
METHODS OF OBSERVATION AND CALCULATION.
I. Instruments: a. Theodolites; b. Chronometers; c. Meteorological Instruments.—Mode of packing.
II. Introductory Calculations: a. Refraction; b. Parallax; c. Methods of Interpolation, Quantities depending on
the Yearly Motion, or on the Anomalies in the Orbit, and Quantities depending on the Daily Motion.
III. Methods tor calculating Latitude and Time: 1. Observations of Stars. 2. Observations of the Sun: Method 1.,
for unequal Altitudes; Method II., for corresponding Altitudes; Method III., for circum-meridian Altitudes.
3. Determination of the Meridian.
IV. Methods for calculating the Longitude: 1. Longitude by Chronometers. Rates of the Chronometers used:
a. Chronometer 3, 1854 to 1857; b. Chronometers 1 and 2, 1854 to 1856; c. Chronometer 1, 1856 and 1857;
cl. Chronometer 4; e. Resulting Table of Rates. 2. Longitude by Celestial Phenomena: a. Lunar Distances;
h. Eclipse of the Moon, October, 1856, with physical remarks.—Terrestrial signals.
V. Method of Equations of Condition: a. Application to Latitudes; b. Example for Latitude; c. Application to
Longitudes.
I. INBTKUMENTS.
a. THEODOLITES.
A he instruments for angular measurements which we used were the following:
Theodolite 1, Jones.1 It had a horizontal circle of 5, and a vertical circle of
4Vo inches diameter. The horizontal circle had three verniers, reading 30 seconds; the
two verniers of the vertical circle gave the minutes.3 There was also a tangential
screw, which allowed of repetitions being made. For surveying purposes, as well as
for an approximate determination of the declination, a magnet could be screwed
upon the telescope. The levels were large. and always remained in very good order.
1 Jones, 4, Rupert Street, London.
2 The mean of the verniers and the use of the repetition apparatus allowed of 10 seconds being estimated with
sufficient accuracy. In some cases, even 5 seconds or less were noted, being then the mean of several readings.
This remark also applies to our other theodolites.
I. 10