THE

THEORY AND PRACTICE

OF FINDING THE

LONGITUDE

AT SEA OR LAND.

VOL. II.

THE

THEORY AND PRACTICE

OF FINDING THE

LONGITUDE

AT SEA OR LAND:

TO WHICH ARE ADDED,

VARIOUS METHODS OF DETERMINING

THE LATITUDE OF A PLACE,

AND

VARIATION OF THE COMPASS;

WITH

NEW TABLES.

BY

ANDREW MACKAY, LL. D, F. R. S. Edin.

HONORARY MEMBER OF THE LITERARY AND PHILOSOPHICAL SOCIETY OF NEWCASTLE-
UPON-TYNE, AND MATHEMATICAL EXAMINER TO THE HONOURABLE

THE CORPORATION OF TRINITY-HOUSE, THE HONOURABLE
THE EAST INDIA COMPANY, CHRIST'S HOSPITAL, ETC.

IN TWO VOLUMES.

THE THIRD EDITION, IMPROVED AND ENLARGED.

VOL. II.

Cæli enarrant Gloriam Dei.

LONDON:

PRINTED FOR AND SOLD BY THE AUTHOR,

No. 2, George Street, Trinity Square, Tower Hill;

AND BY THE PRINCIPAL BOOKSELLERS IN THE UNITED KINGDOM.

ENTERED AT STATIONERS' HALL,

ACCORDING TO ACT OF PARLIAMENT.

To reduce the true, Altitude of the Sun to its apparent Altitude

TABLE XI.

To reduce the true Altitude of the Moon to its apparent Altitude

TABLE XII.

To reduce the true Altitude of a fixed Star to its apparent Altitude

TABLES XI1I. XIV. XV. AND XVI.

To reduce the Declination of the Sun to any given Meridian, and to any

given Time under that Meridian

TABLE XVII.

For selecting a proper Star from which the Moon's Distance ought to be observed,

that as little as possible of the Moon's proper Motion may be lost

56

TABLE XVIII.

To reduce the right Ascension of the Sun to any given Meridian, and to any given

Time under that Meridian

57

TABLE XIX.

To reduce the Declination, Right Ascension, Horizontal Parallax, and Semidiameter

of the Moon, to any given Meridian, and to any given Time under that Meridian

TABLE XX.

To reduce the Time of the Moon's Passage over the Meridian of Greenwich to the

59

ib

ib.

53