Gould, Lucius D., b. 1814. [from old catalog] · New York, A.J. Bicknell & co. · leaf 134
Plate 31 ExMhits the ground planfoi 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 Fig.…
Stair building
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