THE

THEORY AND PRACTICE

OF FINDING THE

LONGITUDE

AT SEA OR LAND.

VOL. I.

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. I.

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,

BY R. WILKS, 89, CHANCERY LANE.