Projective Abhandlung über Steinschnitt, Constructionen von Mauerflächen, Gewölben und Treppenbau
Wehrle's 1869 German treatise on projective stonecutting, published by Hofer, sets out geometric constructions for masonry walls, vaults and staircases for technical draughtsmen and builders. The pictures are hand-ruled orthographic plates in pale ochre and rose washes, with lettered construction lines, labelled plan points and oblique projections of stone blocks that a designer could borrow for diagrammatic layouts.










