The mariner's instructor [electronic resource] : Being an easy and expeditious method, whereby a master may teach the art of navigation in a short time: design'd chiefly for those persons who cannot spare more time in learning it than is absolutely necessary. Containing the gregorian or new calendar: the description and use of the plain and gunter's scale; geometrical problems: plain, traverse, and mercator's sailing. Parallel, middle latitude, oblique, and current sailing: rules an directions to work an observation: the method of finding the variation of the compass by the sun's azimuth and amplitude. Together with the plain and Mercator's charts, with directions how to prick them: as also the method of keeping a journal at sea: with rules and directions for correcting the dead-reckoning by an observation. To which are added tables of logarithms and logarithmic sines and tangents; and a useful figure for the more readily working a day's work to be enter'd in a journal. By William Puddicombe of Topsham.