224 Make the following addition to the example worked out :

237 In the example worked out the horizontal parallax should be

205 The analytical expression in this page is incorrectly printed:

it will be found correct in its proper place in Part II.

14° 55'

50° 48' N.

99

A.M.

99

CONTENTS.

NAVIGATION.

Fage

Definitions

Given lat. from and lat. in, to find true diff. lat.
Given lat. from and lat. in, to find merid. diff. lat.
Given lat. from and lat. in, to find middle lat.
Given long. from and long. in, to find diff. of long.
Given lat. from and true diff. lat., to find lat. in
Given long. from and diff. long., to find long. in.
Description of compass and log line

3

5

7

8

10

11

13

13

15

16

17

19

Given compass course and variation, to find true course

Deviation of compass from local attraction

Given compass course, variation and deviation, to find true course.

Given true course, variation and deviation, to find compass course.

Given compass course, variation, deviation, and leeway, to find

I. Given lat. and long. in, to find course and distance (by meri-

dional parts)

20

II. Given course and distance, to find lat. and long. in (by meri-

dional parts).

23

III. Given lat. and long. in, to find course and distance (by middle

lat.)

IV. Given course and distance, to find lat. and long. in (by middle

lat.)

V. Parallel sailing: to find course and distance

VI. Parallel sailing: to find lat. and long. in

NAUTICAL ASTRONOMY.

Astronomical and Nautical terms and definitions .

The solar year and sidereal year

To find the length of the mean solar year

To find the length of the sidereal year

The sidereal day, the apparent solar day, and the mean solar day. 61

To find the daily motion of the mean sun in the equator

63

To find the arc described by a meridian of the earth in a mean

solar day

63

Sidereal time, apparent solar time, and mean solar time

64

The equation of time.

Sidereal clock and mean solar clock

Nautical and astronomical day.

64

64

65

Rules in Nautical Astronomy.

I. Given civil or nautical time to find astronomical time

II. Given astronomical time to find civil or nautical time

To find the time at any place having given the Greenwich
time and longitude.

III. To reduce degrees into time

IV. To reduce time into degrees

V. To find the Greenwich date (first method)

VI. To find the Greenwich date (second method)

Explanation and use of the Nautical Almanac.

VII. To take out of the Nautical Almanac for any given time

the sun's declination (first method)

VIII. To take out the sun's declination (second method)

IX. To take out the equation of time

74

75

77

X. To take out the moon's semi-diameter and horizontal parallax 78

XI. To take out the sun's right ascension

81

XII. To take out the moon's declination and right ascension .

XIII. To take out the right ascension of the mean sun

XIV. To take out the lunar distance for any given time at

Page

XV. To find the time at Greenwich corresponding to a given

lunar distance

8888

86

To take out a planet's right ascension and declination . 87

XVI. Given mean solar time and the equation of time to find

apparent solar time, and the converse

XVII. Given mean solar time to find sidereal time.

XVIII. Given apparent solar time to find sidereal time

XIX. To find what heavenly body will pass the meridian the

next after a given time

XX. Given sidereal time to find mean time

XXI. Given hour angle to find ship mean time

90

XXII. To find at what time any heavenly body will pass the

XXIII. Given a star's observed altitude to find its true altitude

XXIV. Given a planet's observed altitude to find its true

104

104

105

105

106

XXV. Given the sun's observed altitude to find its true

altitude

109

.

XXVI. Given the moon's observed altitude to find its true

altitude

110

Rules for finding the Latitude.

XXVII. To find the latitude by meridian altitudes of a circum-

XXVIII. To find the latitude by sun's meridian altitude

XXIX. To find the latitude by sun's meridian altitude in arti-

ficial horizon

XXX. To find the latitude by moon's meridian altitude
XXXI. To find the latitude by star's meridian altitude
XXXII. To find the latitude by planet's meridian altitude
XXXIII. To find the latitude by meridian altitude under the

pole

XXXIV. To find the latitude by sun's altitude near the meridian
XXXV. Correction for run of the ship in double altitude.

XXXVI. To find the latitude by double altitude of sun.

XXXVII. To find the latitude by double altitude of two stars
observed at same time

XXXIX. To find the latitude by double altitude of two stars

observed at different times

XL. Ivory's Rule for finding the latitude by sun double

altitude

XLI. To find the longitude from the above observations
XLII. Given, error and rate of chronometer, to find
Greenwich mean time at some instant

XLIII. To find error of chronometer on mean time at the
ship by a single altitude of the sun

XLIV. To find the error of chronometer on mean time at

170

Greenwich by a single altitude of the sun

172

XLV. To find error of chronometer on mean time by single

XLVI. To find error of chronometer by equal altitudes

183

Rules for finding the Longitude.

XLVII. To find the longitude by chronometer and altitude of

XLVIII. To find the longitude by chronometer and star

L. To find the longitude by sun lunar (ship time deter-

mined from sun's altitude)

211

LI. To find the longitude by sun lunar (ship time deter-

mined from moon's altitude)

217

LII. To find the longitude by star lunar (ship time deter-

mined from star's altitude)

221

LIII. To find the longitude by star lunar (ship time deter-

mined from moon's altitude)

226

LIV. To find the longitude by planet's lunar (ship time

determined from planet's altitude)

Longitude by lunar-altitudes calculated to find ship

mean time

LV. To find longitude by sun lunar, altitudes calculated. 230

LVI. To find longitude by star lunar, altitudes calculated. 236