# Field Engineering: A Handbook of the Theory and Practice of Railway Surveying, Location and Construction, Volumes 1-2

J. Wiley, 1919 - Railroad engineering

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Page 265 - The limits of free haul shall be determined by fixing on the profile two points — one on each side of the neutral grade point — one in excavation and the other in embankment, such that the distance between them shall equal the specified free-haul limit and the included quantities of excavation and embankment balance.
Page 332 - All numbers which consist of the same figures standing in the same order have the same mantissa, regardless of the position of the decimal point in the number, or of the number of ciphers which precede or follow the significant figures of the number. The value of the characteristic depends entirely on the position of the decimal point in the number. It is always one less than the number of figures in the number to the left of the decimal point. The value is therefore diminished by one every time...
Page 335 - Take out from the proper column of the table the logarithm corresponding to the given number of degrees and minutes. If there be any seconds multiply them by the adjoining tabular difference, and apply their product as a correction to the logarithm already taken out. The correction is to be added if the logarithms of the table are increasing with the angle, or subtracted if they are decreasing as the angle increases. In the first quadrant the log sines and tangents increase, and the log cosines and...
Page 333 - The first three figures of a number are given in the first column, the fourth at the top of the other columns. The first two figures of the mantissa are given only in the second column, but these are understood to apply to the remaining four figures in either column following, which are comprised between the same horizontal lines with the two. If a number (after cutting off the ciphers at either end) consists of not more than four figures, the mantissa may be taken direct from the table ; but by...
Page 334 - Table XXIV is a small table of logarithms of numbers from 1 to 100, with the characteristic prefixed, for easy reference when the given number does not exceed two digits. But the same mantissas may be found in the larger table. TABLE XXV.
Page 337 - ... lies between 88° and 92°, or between 178° and 180°; but if the number of degrees be found at the bottom of the page, the title of each column will be found there also; and if the number of degrees be found on the...
Page 265 - All material within this limit of free haul shall be eliminated from further consideration. The distance between the center of gravity of the remaining mass of excavation and center of gravity of the resulting embankment, less the limit of free haul as above described, shall be the length of overhaul. The compensation to be rendered therefor shall be determined by multiplying the yardage in the remaining mass, as above described, by the length of the overhaul.
Page 212 - When a transit bas a level-tube attached to the telescope, it may bu used as a Theodolite for levelling, and for taking vertical angles. If the instrument be in perfect adjustment, the line of sight will be horizontal when the bubble stands at the middle point of the tube, and the reading of the vertical circle will be zero. Should there be a small reading when the line of sight is horizontal it is called the index error. When the line of sight is not horizontal, the angle which it makes with the...
Page 332 - ... of the calculation. By this rule we have Number Logarithm 1.384 0.141136 .1384 9.141136 .01384 8.141136 .001384 7.141136 etc. etc. No confusion need arise from this method in finding a number from its logarithm; for although the logarithm 6.141136 represents either...