Cyclopedia of Civil Engineering; A General Reference Work on Surveying, Railroad Engineering, Structural Engineering, Roofs and Bridges, Masonry and R

Cyclopedia of Civil Engineering; A General Reference Work on Surveying, Railroad Engineering, Structural Engineering, Roofs and Bridges, Masonry and R

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This historic book may have numerous typos and missing text. Purchasers can download a free scanned copy of the original book (without typos) from the publisher. Not indexed. Not illustrated. 1913 edition. Excerpt: ...if they had been run north from the next southern parallel. This point is obtained from computation, and is less than twenty-four miles from the next eastern or western meridian by the convergence of the meridians in twentyfour miles. In case guide meridians have been improperly located too far apart, auxiliary meridians may be run from standard corners, and these may be designated by a local name. The angular convergence of two meridians is given by the equation f = m sin L (1) where m is the angular difference in longitude of the meridians, and L is the mean latitude of the north and south length under consideration. The linear convergence in a given length l is c = l sin $ (2) The radius of a parallel at any latitude L is given by the equation r = cos L (3) where R is the mean radius of curvature of the earth. The distance between meridians is usually given in miles and this must be reduced to degrees. To do this it is first necessary to find the linear value of one degree of longitude at the mean latitude from the proportion. 1: 360:: x: 2-nr (4) the value of r being found from (3) Equation (4) will give results sufficiently accurate, although in strict accuracy R should be the radius of curvature at the mean latitude. For full details of public-land surveying, see "Manual of Surveying Instructions for the Survey of the Public Lands of the United States," issued by the Commissioner of the General Land Office. These " Instructions " are prepared for the direction of those engaged on the public land surveys, and new editions are issued'from time to time. Much of the foregoing in very condensed form i9 taken from the edition of 1894. The following table gives the convergency both in angular units and linear units for township...show more

Product details

  • Paperback | 94 pages
  • 189 x 246 x 5mm | 181g
  • Rarebooksclub.com
  • United States
  • English
  • black & white illustrations
  • 1236497287
  • 9781236497284