This historic book may have numerous typos and missing text. Purchasers can download a free scanned copy of the original book (without typos) from the publisher. Not indexed. Not illustrated. 1880 Excerpt: ...this instrument, a level-or a vane-staff, a strong 50-feet cord or chain, plenty of pegs and one or two mallets, the pegging-out of 50 feet or 25 feet distances to any predetermined incline may be rapidly done on bare ground; but if the land is particularly woody and difficult, men with axes and billhooks must be ...
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This historic book may have numerous typos and missing text. Purchasers can download a free scanned copy of the original book (without typos) from the publisher. Not indexed. Not illustrated. 1880 Excerpt: ...this instrument, a level-or a vane-staff, a strong 50-feet cord or chain, plenty of pegs and one or two mallets, the pegging-out of 50 feet or 25 feet distances to any predetermined incline may be rapidly done on bare ground; but if the land is particularly woody and difficult, men with axes and billhooks must be employed to clear the way as the work proceeds. As an example let 1 in 20 be the gradient to be set-out; this gives a rise or fall of 2 feet in 50, and if the support for the reflecting level be 5 feet, the reading on the level staff for every 50 feet should be 7 feet; if a vane-staff be used the vane should be set to this height; then with the aid of the 50-feet chain, points can be marked or pegged on the ground which will follow the required gradient. This pegging should be connected by cords by a laboring party immediately following, and used as a centre line for a footpath 3 feet wide to be made at once for the convenience of men and animals, as well as for enabling the engineer to go over the whole of this work with a levelling instrument before the bridges and other works are commenced. On hill-roads the calculation and setting-out the sidewidths is roughly done on the principles already explained, page 204. The final breadth of formation of a hill-road is generally 12, 18, 21, or 24 feet, exclusive of the drain on the inner side in side cutting. As to gradients, 1 in 20 is the steepest ascent for wheeled vehicles that can be continued for many miles without causing animals extreme fatigue, it is also the steepest declivity for a horse to canter down for a long distance; a gradient of I in 16 should never be continued in exceptional places for more than a quarter of a mile, nor one of 1 in 8 for more than 50 feet; this being the limiting max...
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Add this copy of Aid to Survey-Practice to cart. $64.31, good condition, Sold by Bonita rated 4.0 out of 5 stars, ships from Santa Clarita, CA, UNITED STATES, published 2010 by Nabu Press.
