654
Molesworth’s pocket-book
Curves—conti
Divide the circumference of a
quadrant and the radius AB into
the same number of equal parts;
then the intersection of the respec-
tive lines as drawn in the diagram
gives points in the curve.
sin. a (r — æ)
V — — -----------•________
V r2 — sin. a?
x — ’0636 r z.
Plan of Settingcut a Camber or Flat Curve.
Join AC and produce the line AC until it cuts the per-
perdicular line B E. Divide the half span B D into any con-
venient number of parts, and on each division erect a per-
pendicular. Also divide B E into the same number of parts.
Then lines radiating from the divisions on E B to the point
A will at their intersection with the perpendiculars give
points in the curve.
ANOTHER PLAN.
Join AC and draw the line AD at right angles to AC
until it cuts the horizontal tangent line CD. Also draw
A E perpendicular to the line AB. Divide the halt chord
A B into any convenient number of parts, also DC and A E
into the same number of parts. Then lines radiating to C
from the divisions on A E will at their intersection with the
lines which join the divisions on AB and D C give points In
the curve.