An edition of The sectorian system of handrailing (1873)

The sectorian system of handrailing

... elucidating the whole subject by the introduction of fifteen plates, with suitable letter-press notes on each plate. The principle is entirely new, and adapted to the construction of wreaths for stairs, however difficult, by the use of the sector, a mathematical instrument founded on the fourth proposition of the sixth book of Euclid, and adapted to this system.

By Forbes, William