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. 1909 edition. Excerpt: ...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 is taken from the edition of 1894. The following table gives the convergency both in angular units and linear units for township 6 miles square, between latitudes 30 and 70 north. Let it be required to find from the table the linear convergence for a township situated in latitude 38 29' north. Looking in the table opposite 39 we find the linear convergence. For 39 = 58.8 links For 38 = 56.8 links Difference for 1 = 2.0 links Difference for 1' = 2.0-f-60 =.0333 links Difference for 29' =.0333 X 29 =.97 links Therefore total convergence for latitude 38 29' = 56.8 + 0.97 links = 57.77 links. BASE nEASUREHENT. It is not intended in what follows to go into the details of the measurement of a base for an extended system of triangulation, as that properly belongs to Geodetic Surveying. Some description of base measuring apparatus will be given, with illustrations of various devices, and special attention will be given to the use of the tape in the accurate measurement of lines such as occur in usual field operations of Plane Surveying. Much of what follows is from the excellent treatise on Topographic Surveying by Herbert M. Wilson. A trigonometric survey is usually carried over a country where the direct measurement of distances is impracticable, and since the calculations of these distances proceeds from the direct measurement of the base-line, this base line should be so located as to permit of its length being determined with any degree of accuracy consistent with the nature of the work involved....show more

Product details

  • Paperback | 96 pages
  • 189 x 246 x 5mm | 186g
  • Rarebooksclub.com
  • Miami Fl, United States
  • English
  • black & white illustrations
  • 1236602048
  • 9781236602046