Presentation of J . H . Lambert ’ s text “ Vorstellung der Größen durch Figuren ” ( with two analyses of Lambert ’ s practice of visual strategies in his experimental studies )

J.H. Lambert was one of the first scientists to use graphs to represent and analyse his (experimental) data. This article presents Lambert’s text “Vorstellung der Größen durch Figuren” that contains his most detailed discussion on the usability of graphs in (experimental) science. This text is put into the broader context of Lambert’s philosophical and mathematical work and illustrated by the analysis of two graphs. Two conclusions should be mentioned. First, for Lambert, visualisation is a technique complementary to the algebraic processing of data. Second, Lambert’s graphical techniques and strategies are the continuation and perfection of an older tradition that may be called “Archimedean”.