This section is from the book "Cyclopedia Of Architecture, Carpentry, And Building", by James C. et al. Also available from Amazon: Cyclopedia Of Architecture, Carpentry And Building.
The ultimate crushing strength of stone varies greatly. The crushing strength is usually determined by making tests on small cubes. Tests made on prisms of a less height than width show a much greater strength than tests made on cubes of the same material, which shows that the bearing strength of rock on which foundations are built is much greater than the cubes of this stone. In Table I, Part I, the lowest value given for the crushing strength of a cube is 2,894 pounds per square inch, which is equal to 416,736 pounds per square foot. This shows that any ordinary stone which is well imbedded will carry any load of masonry placed on it.