# A Treatise on the Principles and Practice of Levelling, Showing Its Application to Purposes of Civil Engineering, Particularly in the Construction of Roads

J. Weale, 1856 - Leveling - 214 pages
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Page 11 - A Treatise on the principal Mathematical Instruments employed in Surveying, Levelling, and Astronomy...
Page 95 - Well-made roads, formed of clean, hard, broken stone, placed on a solid foundation, are very little affected by changes of atmosphere ; weak roads, or those that are imperfectly formed of gravel, flint, or round pebbles, without a bottoming or foundation of stone pavement or concrete, are, on the contrary, much affected by changes of the weather. In the formation of such roads, and before they become bound or firm, a considerable portion of the subsoil mixes with the stone or gravel, in consequence...
Page 72 - The area of each end added to four times the middle area, and the sum multiplied by the length divided by 6, will give the solid content. If the measures used in the calculation are yards, the result will be the content in cubic yards ; but if they are feet, the result must be divided by 27, to obtain the corresponding number of yards. CALCULATION OF THE TRIANGULAR PORTION O.
Page 92 - ... one ; for it wears so rapidly that the crust of a road made with it always consists of a large portion of the earthy matter to which it is reduced. This prevents the gravel from becoming consolidated, and renders a road made with it extremely defective with respect to that perfect hardness which it ought to have.
Page 51 - ... reduced thereto), otherwise the section will be longer than it ought to be. For the purpose of assisting the surveyor in making the necessary reduction from the hypothenusal to the horizontal measure, when laying down...