レヒラーの「教本」における方立てと横断アーチの設計法

抄録

This paper analyze the design methods of drawings of the mullion and the transverse arch by Lorenz Lechler. He was the late gothic "Baumeister" in Heidelberg and wrote the book called "Unterweisung". He instructed to design those drawings of templates of two sizes of "alt" (old, large) and "jung" (young, small) as in the ratio 7 : 5. The result shows it described by the following means : (1) Two scales in the ratio 7 : 10 in each unit. (2) The scheme consisted three inscribed squares that has the sides as in the ratio 10 : 7 : 5.