A practical treatise on foundations, explaining fully the principles involved : with descriptions of all of the most recent structures, accompanied by numerous drawings ... (1893)
Patton, William Macfarland, 1845-1905 · New York : John Wiley · leaf 437
Plate II. Ends Large Stone. Fig. i. Circular Backing. … Triangular-end Rubble Backing. Fig. 2. Pointed-end Concrete Backing.
Foundations
Internet Archive · Getty Research Institute · Public domain (published before 1931). Free to use for anything.
