Principle XLII.

There is but one correct method of checking thoroughly the entire detailing of a finished design for a structure, viz.: "Follow each stress given on the stress-diagram from its point of application on one main member until it is transferred completely to either other main members or to the substructure, and see that each plate, pin, rivet, or other detail by which it travels has sufficient strength in every particular to resist properly the stress that it thus carries; check also the sizes of such parts as stay-plates and lacing, which are not affected by the stresses given on the diagram, and see that said sizes are in conformity with the best modern practice."

But to do all this as it should be done necessitates the computer's being, in the highest sense of the term, an "expert on structural metal-work."