ABSTRACT
Up to the late 18th century structures were designed essentially on the basis of proportion. To some extent this meant no more than deciding whether sizes looked right - that is, familiar - but in many, perhaps almost all, periods there were some rules or statements by authorities which were almost as firm as our codes of practice today. The difference is that they were not based on strength or stress but on shape and scale. Stress in the sense that we use the word in engineering today did not exist.
