Hi, Thomas M. Humphrey, using not only English translations but also French and German orginals gave a well documented survey of this stuff in "Marshallian Cross Diagrams and Their Uses before Alfred Marshall: The Origins of Supply and Demand Geometry" ECONOMIC REVIEW, MARCH/APRIL 1992, FEDERAL RESERVE BANK OF RICHMOND it can be downloaded at : http://www.richmondfed.org/publications/economic_research/economic_review/pdfs/er780201.pdf Alain Alcouffe