Of these requirements, the knowledge is the only thing that a book can supply; it was with this limited object that this work was written. The attainment of the capability for carrying out ordinary general and route surveys, treated in this volume, involves but little special technical knowledge, and may rather be now regarded as one of those acquirements which, like drawing, should be invariably comprised in the ordinary education of an English gentleman, as it may be useful at any time either in England, at the tropics, or in any foreign country or colony. Keeping the before-mentioned purposes in view, this book has been arranged accordingly, special care having been taken that no exclusively local terms should be introduced; while such operations as are exclusively confined to Great Trigonometrical Surveys, which involve the use of three-feet theodolites and compensating bars, the construction of towers and scaffolds 40 and 50 feet in height, the clearance of hill-tops, and miles of visual ray for enormous triangulations, have been referred to merely as far as they give indications useful for guidance in ordinary Surveying. L. D'A. J. Royal Institution, Albemarle Street. Troughton's repeating reflecting circle Gauss' principle of Suspension 4. Formula for trigonometrical calculations. Legendre's solution of a spherical triangle Local mean radius of curvature. Colonel Clarke's computed dimensions of the Earth Calculation of latitudes, longitudes, and azimuths The same by approximate formulæ |