A treatise of navigation [electronic resource] : containing, I. The theory of navigation demonstrated; wherein it is proved, that the Nature of the thing called Departure is quite different from that which the Writers upon this Subject took it to be: That Middle-Latitude Sailing is erroneous; and that the common Method of keeping Reckonings in Meridional Distance, is grossly false. II. Nautical problems: Of a single Course, Traverses; of computing the Bearings and Distances of Places. The Use of Mercator's Chart made easy, and a new Method for finding the Bearings of Places upon Charts, without the Confusion of Rhumb-Lines. Of Currents, and how to find them several Ways: Of turning to Windward in Currents, &c. III. Astronomical Problems: Improvements made in the common Sea-Quadrant. The Description of a new Fore-Staff, which is much more accurate and commodious than the common one. The Errors of the Nocturnal shewed and demonstrated. Tables of the Sun's Place, Declination, and Right Ascension. A Table of the most eminent Fixed Stars, contrived in such a manner, as to shew by Inspection, which is the properest Star for Observation, in all Places, and at all Times of the Year. IV. Practical Navigation: Improvements made in the common Sea-Compass. The Description of a new Azimuth-Compass, which is so contrived as to be kept from being disturbed by the Motion of the Ship. How to find the Lee-Way to a great Exactness, and a new and commodious Method of keeping a Sea-Journal. To which is prefixed, by way of Introduction, A succinct Treatise of Plain Trigonometry. By Joseph Harris, teacher of the mathematicks.