Course of Civil Engineering: Comprising Plane Trigonometry, Surveying, and Levelling. With Their Application to the Construction of Common Roads, Railways, Canals ...

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S.J. Machen, 1843

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Page 188 - ... the height of every embankment, and the depth of every cutting, and a datum horizontal line which shall be the same throughout the whole length of the work, or any branch thereof respectively, and shall be referred to some fixed point stated in writing on the section, near some portion of such work, and, in the case of a canal, cut, navigation, public carriage road, or railway, near either of the termini.
Page 75 - All the irregularities of the upper part of the said pavement are to be broken off by the hammer, and all the interstices to be filled with stone chips firmly wedged or packed by hand with a light hammer, so that when the whole pavement is finished there shall be a convexity of four inches in the breadth of fifteen feet from the centre.
Page 176 - ... boat is 4320 cubic feet, and in ascertaining what water may be necessary for supplying the canal, allowing for waste by evaporation and soakage, it is found (according to the number of boats that may be expected to pass), that there will not be above 800 cubic feet for each ; and hence, it is added, it will be necessary to save five-sixths of the whole ; to do which ten cisterns are directed to be made, each of which must be one foot deep, and each have a surface of 360 feet superficial. The...
Page 75 - The middle 18 feet of pavement is to be coated with hard stones to the depth of 6 inches. Four of these 6 iuches to be first put on and worked in by carriages and horses, care being taken to rake in the ruts until the surface becomes firm and consolidated, after which the remaining 2 inches are to be put on.
Page 151 - ... down again, a portion of a continuous flexible valve or flap, of peculiar construction, covering the aperture ; and it is the very simple, ingenious, and efficient mode of successively opening, and closing down and hermetically sealing this valve, as each train advances and moves on, that constitutes the merit of the invention, and the foundation of the patent ; the operation consisting first, in opening the valve to admit the free admission of the external air, to press on the back of the piston,...
Page 75 - Four of these six inches to be first put on, and worked in by carriages and horses ; care being taken to rake in the ruts until the surface becomes firm and consolidated, after which the remaining two inches are to be put on.
Page 243 - Europe occupy the place of immense forests of pine and oak, which have many of them disappeared within the historical era. Such changes are brought about by the fall of trees and the stagnation of water, caused by their trunks and branches obstructing the free drainage of the atmospheric waters, and giving rise to a marsh.
Page 2 - Also one place is higher than another, or out of level with it, when it is farther from the centre of the earth : and a line equally distant from that centre, in all its points, is called the line of true level. Hence, because the earth is round, that line must be a curve, and make a part of the earth's circumference, or at least be parallel to it, and concentrical with it ; as the line BCFG, which has all its points equally distant from A,.
Page 240 - A velocity of six inches will lift fine sand, eight inches will lift sand as coarse as linseed, twelve inches will sweep along fine gravel, twentyfour inches will roll along rounded pebbles an inch diameter, and it requires three feet per second at the bottom to sweep along shivery angular stones of the size of an egg.
Page 75 - Upon the level bed prepared for the road materials, a bottom course, or layer of stones, is to be set by hand, in form of a close firm pavement ; the stones set in the middle of the road are to be 7 inches in depth ; at 9 feet from the centre, 5 inches ; at 12 feet from the centre, 4 inches ; and at 15 feet, 3 inches.

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