Gould, Lucius D., b. 1814. [from old catalog] · New York, A.J. Bicknell & co. · leaf 136
Plate 31 Exhibits the ground plan for a circular staircase ; the wreath in four pieces. To find the common pitch, at Fig. 2, extend the tangent C D to A; at rightangles to A C, draw A J, equal to five risers, join C J ; then C J is the pitchof the tangents, that meet at the joints F C and N. At…
Stair building
Internet Archive · Library of Congress · Public Domain Mark 1.0. Free to use for anything.
