Usus et Fabrica Circini Cuiusdam Proportionis
Usus et Fabrica Circini Cuiusdam Proportionis is a 1655 Latin treatise by Balthasar Capra on the use and construction of a proportional compass, written for surveyors, instrument makers and mathematicians. Its pictures are plain geometric line diagrams of triangles and sight lines labelled with capital letters, with angle arcs at the points of observation, giving a designer clear, schematic structures for diagrams or technical layouts.
