aided me in all subsequent Editions, have made many alterations and improvements that long experience and unremitted attention have suggested: I trust, therefore, that the "Complete Epitome of Practical Navigation" will continue to merit that approbation which it has always hitherto experienced, from a liberal and enlightened Public. J. W. NORIE.
In the present edition, various improvements have been made to facilitate and simplify the many subjects it contains ; among which, has been shewn the method of determining the Latitude by an altitude of the Polar Star, examples being given in reference to the Rules, as stated in the Nautical Almanac for 1854 (vide page 636), in which will be found Rules, with an example on this subject.
Examples are worked in this Edition, shewing how the variation of the compass by an azimuth may be obtained, by the sights taken for determining the Longitude by chronometer. (vide pp. 245 and 246.
A very concise and simple method of determining the Longitude by Lunar Observations, is inserted, being the shortest of any hitherto proposed, called "LYON'S METHOD IMPROVED :" it consists of Addition throughout, and is performed by Tables common to all Books on Navigation and Nautical Astronomy, except that which determines the third arc; the whole of the operation contained between the apparent distance and the true is obtained by three tables, and consists of eight lines only. The Table, (LVII) shewing the times of High Water on Full and Change days of the Moon, &c., has been considerably enlarged, and inserted from the latest authorities to the present time.
This edition of the Epitome of Navigation (with the Examples it contains) has been carefully computed and adapted for the year 1854, in order that the learner may procure the Nautical Almanac for that year, and thereby be enabled to go through the various calculations inserted, with the assistance of that valuable and indispensable publication.