Altitude Tables, computed for Intervals of Four Minutes between the Parallels of Latitude 0° and 30° and Parallels of Declination 0° and 24°, designed for the Determination of the Position-line at all Hour Angles without Logarithmic Computation

Abstract

THE appearance of a second and improved edition of these tables is welcome on several grounds, but mainly as an indication of increasing accuracy in nautical calculations. We hope, too, that the demand for such tables may be regarded as a proof of the growing popularity of the method of determining the position of a ship at sea proposed by Captain Marcq St. Hilaire, of the French Navy. This method, though theoretically superior to that of finding the Sumner lines by the ordinary process, has not been generally adopted, on account of the slight increase in the computations required. Seeing that in the St. Hilaire method, the observations may be made at any time with equally good and consistent results, whereas in the ordinary method, observations taken near the meridian may have to be repeated nearer the prime vertical, the objections that have been alleged against the newer method on account of the length of the observations ought not to be allowed to prevail. The sailor expects to find tables at hand that shall curtail the arithmetical processes to a minimum, and these tables, the main feature of which is to give readily and accurately, at sight, the altitude of the sun or of stars within the ecliptic limits, at least in the more frequented latitudes, will remove one of the objections that have been urged.

Altitude Tables, computed for Intervals of Four Minutes between the Parallels of Latitude 0° and 30° and Parallels of Declination 0° and 24°, designed for the Determination of the Position-line at all Hour Angles without Logarithmic Computation.

By F. Ball. Second edition. Pp. ix + 245. (London: J. D. Potter, 1910.) Price 15s. net.