. Railroad construction. Theory and practice . Fig. 5. Plot the results in a note-book which is ruled in quarter-inchsquares, using a scale of 100 feet per inch in both the work up the page; then when looking ahead along theline, the work is properly oriented. When a contour crosses — Fig. 6. the survey line, the place of crossing may be similarly deter-mined. If the ground flattens out so that five-foot contours arevery far apart, the absolute elevations of points at even fifty- § 13. RAILROAD SURVEYS. 13 foot distances from the renter should be determined. Themethod m ex
. Railroad construction. Theory and practice . Fig. 5. Plot the results in a note-book which is ruled in quarter-inchsquares, using a scale of 100 feet per inch in both the work up the page; then when looking ahead along theline, the work is properly oriented. When a contour crosses — Fig. 6. the survey line, the place of crossing may be similarly deter-mined. If the ground flattens out so that five-foot contours arevery far apart, the absolute elevations of points at even fifty- § 13. RAILROAD SURVEYS. 13 foot distances from the renter should be determined. Themethod m exceedingly rapid. Whatever error or inaccuracy-occurs IS confined in its effect to the one station Avhere it work being thus plotted in the field, \inusuallv irregulartopography may l)e plotted with greater (-ertainty and no gK-aterror can occur without detection, it would even be possibleby this method to detect a gross error that might have beenmade by the le\el party 13. Stadia method. This method is best adapted to fairlyopen country where a ^\shot to any desired point may betaken without clearing. The backbone sur\e\ hne is the sameas in the previous method except that each course is limited tothe practicable length of a stadia sight. The distance betvveenstations should be checked
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