Musées de Langres – Maison des Lumières Denis Diderot – Musée d'Art et d'Histoire

The case holds ten instruments, some of them signed Michael Butterfield, a manufacturer of scientific instruments based in Paris. The set includes instruments for measuring (protractor, sector, folding square, divider) and drawing straight lines (rule, ruling pen), right angles (square) and circles (two compasses). Diderot used similar tools for his own studies on squaring the circle.