The Civil engineer and architect's journal, scientific and railway gazette . Fig. 1,—Cutting. In the case of an embankment (fig. 2), JT = r X B c = r{K — h + h) — r (K - A) + r 7. = rBa-|-j-ft := a(^ \ rK (2) Hence, whether there be cutting or embankment, we must deter-mine the half-width (aa^ at the level of the line of collimation ; andin making repeated trials, we have nothing more to do than multi-ply the reading of the level-staff (/*) for the slope by )•, and addthe product to a a for embankments, or subtract it for cuttings, toobtain the value of x, which must be compared with the horiz
The Civil engineer and architect's journal, scientific and railway gazette . Fig. 1,—Cutting. In the case of an embankment (fig. 2), JT = r X B c = r{K — h + h) — r (K - A) + r 7. = rBa-|-j-ft := a(^ \ rK (2) Hence, whether there be cutting or embankment, we must deter-mine the half-width (aa^ at the level of the line of collimation ; andin making repeated trials, we have nothing more to do than multi-ply the reading of the level-staff (/*) for the slope by )•, and addthe product to a a for embankments, or subtract it for cuttings, toobtain the value of x, which must be compared with the horizontaldistance (i/), found by measurement with the chain. Repeatedtrials must be made until a point is discovered which satisfies thecondition y ?= Fig. 2.—Embankment. Take, as an example, fig. 1, which is a cutting. B A = K = 26-2 ft.; A = 2-13 ; >• = 1^; aa=rxBa = r(K + A) = 1^(26-2 -f 213) = 42-5; let the staff be held at /, and suppose the reading to be 6S = A; thenrA = 9-75; and j? =// = aa — rh — 42-5 — 9-75 = 32-75. By measurement with the chain, y is found = 22-00; .-. y is not equal to x. Again, suppose the reading ce of the staff ate to be 10-7 = A ; then r A = 16-05; and x — 42-5 — r h = 42-5 — 16-05 = 26-45 >and y is found by measurement to he 26-45/.•. y z= X; and c is the point of an Embankment.—Slopes 1| to 1. Let K = 42-36;A = 2-43. Then (K — A) = B a = 42-36 — 2-43 = 39-93 ;and aa = rx Ba = 1^ X 30-93 = the reading c e of the staff at c to be 10-05 = A,then rh = 15-07 ;X =z aa + rh = 590 + rh = 59-9 -|- 15-07 = 74-97\and suppose that y, found by measurement, is ;= 74-97 J then c will be the required necessary calculations are very simple, but t
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