A treatise on land-surveying; comprising the theory developed from five elementary principles; and the practice with the chain alone, the compass, the transit, the theodolite, the plane table, &cIllustrated by four hundred engravings, and a magnetic chart . bQ 112 CHAIIV SrRVEYIIVG, [part (183) Through a wood. When a -wood intervenes between anj two given Fi?. 119. points, pre-venting onefrom beingseen from the other, as in the figure, in which A and Z are the given points, pro-ceed thus. Hold a rod at some point B as nearly in the desiredline from A as can be guessed at, and as far from
A treatise on land-surveying; comprising the theory developed from five elementary principles; and the practice with the chain alone, the compass, the transit, the theodolite, the plane table, &cIllustrated by four hundred engravings, and a magnetic chart . bQ 112 CHAIIV SrRVEYIIVG, [part (183) Through a wood. When a -wood intervenes between anj two given Fi?. 119. points, pre-venting onefrom beingseen from the other, as in the figure, in which A and Z are the given points, pro-ceed thus. Hold a rod at some point B as nearly in the desiredline from A as can be guessed at, and as far from A as approximate to the proper direction, an assistant may be sent tothe other end of the line, and his shouts will indicate the direction ;or a gun may be fired there; or, if very distant, a rocket may besent up after dark. Then range out the random line AB, bythe method given in Art. (169), noting also the distance from Ato each point found, till you arrive at a point Z, opposite to thepoint Z, i. e. at that pomt of the line from which a perpendicularthere erected would strike the point Z. Measure ZZ. Thenmove each of the stakes, perpendicularly from the hne AZ, a dis-tance proportional to their distances from A. Thus, if AZ be1000 links, and ZZ be 10 links, then a stake
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Keywords: ., bookcentury1800, bookdecade1870, booksubjectsurveying, bookyear18
