10. The following tables may be of assistance. It was needful, calculating them at all, to calculate them right; but of course such exactness as the figures would seem to indicate is unattainable in practice.

D

R

11. TABLE SHOWING THE DISTANCE, D, IN FEET, AT WHICH A STRAIGHT LINE MUST PASS FROM THE NEAREST POINT OF ANY CURVE, STRUCK WITH RADIUS r, IN ORDER THAT A TERMINAL BRANCH HAVING RADIUS R=2 r, AND CONSUMING A GIVEN ANGLE, X, MAY

MERGE IN SAID STRAIGHT LINE.

If R = twice the tabular distance; if R

1r, use half the tabular distance; if R = 3 r, use 4 r, use three times the

=

PLACED

12. TABLE SHOWING THE DISTANCE, d, IN FEET, AT WHICH
CURVES OF CONTRARY FLEXURE MUST BE
ASUNDER IN ORDER THAT THE CONNECTING TANGENT,
T, MAY BE 300 FEET LONG.

164444444 DEGREE OF CURVE.

3.9 5.24 5.92
9.43

6.29 6.35 6.68 6.86 7.00 7.08 7.18 10.38 11.20 11.70 12.20 12.55 12.80 13.06 11.77 13.43 14.64 15.68 16.45 17.09 17.61 18.05 15.65 17.39 18.76 19.90 20.82 21.64 22.31 19.54 21.22 22.76 24.01 25.07 25.97

COOTOUTAWN DEGREE OF CURVE.

8°

1°

2°

3°

Examples.

A 7° and 4° should be 19.9 feet asunder; a 5° and 9° should

be 25.07 feet asunder.

As approximations, for a connecting tangent 400 feet long, take twice the tabular distance: for a connecting tangent 200 feet long, take half the tabular distance.

PROBLEMS IN FIELD LOCATION.

XXVI.-XXXVII.