. Textbook of landscape gardening, designed especially for the use of non-professional students. Landscape gardening. LESSON 8 Use of Compass N the simplest paced surveys no compass is used, the cardinal directions being known with suffi- cient exactness. However, as paced or taped surveys become more elaborate the point is soon reached where directions have to be determined more carefully and horizontal angles read. The use of a hand compass is then the next step. The present lesson takes up the construction and use of the compass in its simpler forms. Compass Construction The essential part
. Textbook of landscape gardening, designed especially for the use of non-professional students. Landscape gardening. LESSON 8 Use of Compass N the simplest paced surveys no compass is used, the cardinal directions being known with suffi- cient exactness. However, as paced or taped surveys become more elaborate the point is soon reached where directions have to be determined more carefully and horizontal angles read. The use of a hand compass is then the next step. The present lesson takes up the construction and use of the compass in its simpler forms. Compass Construction The essential part of a compass is a magnetized needle balanced on a vertical pivot. This needle when given its freedom will swing horizontally till one end points toward the magnetic but not the true north. The ends of the needle are marked in some way to distinguish them; sometimes one end, — usually the north, — is colored blue, sometimes a short transverse bar is placed in the north end, some- times the south end has a small coil of wire wound around it to balance the dip of the needle. Usually the needle is deeper than wide so as to balance better. The needle swings within or over a circular dial which is divided into 360 degrees. The unit of graduation is usually one degree, sometimes one-half degree or on small instruments two or five de- grees. The needle oscillates a good deal and comes to rest slowly. In order to check its motion and bring it to rest more quickly a small clamp is usually provided by which the needle may be raised 34. Please note that these images are extracted from scanned page images that may have been digitally enhanced for readability - coloration and appearance of these illustrations may not perfectly resemble the original Waugh, Frank A. (Frank Albert), 1869-1943. New York, John Wiley & sons, inc. ; [etc. , etc. ]
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Keywords: ., bookcentury1900, bookdecade1920, booksubjectlandsca, bookyear1922
