ficient. Examples are given for finding the latitude by the altitude of the pole-star in the College Examination-Papers at the end of the volume. Another important and very necessary addition will be found in the page of errata. To obtain this, the examples have been recalculated, and the author trusts the principal errata have been discovered: still, in a work like the present, in which so many thousand figures must be used to obtain the answers, it is difficult to avoid mistakes; and it is only after several revisions that a near approach to correctness can be made. ROYAL NAVAL COLLEGE, October 21, 1857. Salter at to of: it should read bearing of, instead of bearing at. { after correction, add +2′ 42′′ and height of eye above the sea. alter latitudes to b. meridian 99 the correction 4′ 38′′ should be added: the correct latitude will then be 54° 53′ 21′′ N. 99 altitudes. equator. 224 Make the following addition to the example worked out : 237 In the example worked out the horizontal parallax should be 205 The analytical expression in this page is incorrectly printed: it will be found correct in its proper place in Part II. 14° 55' 50° 48' N. 99 A.M. 99 CONTENTS. Given lat. from and lat. in, to find true diff. lat. Given compass course and variation, to find true course Deviation of compass from local attraction Given compass course, variation and deviation, to find true course. Given true course, variation and deviation, to find compass course. Given compass course, variation, deviation, and leeway, to find II. Given course and distance, to find lat. and long. in (by meri- |