IIIF provides researchers rich metadata and media viewing options for comparison of works across cultural heritage collections. Visit the IIIF page to learn more. This brass semicircular protractor is ...

In the 18th and 19th centuries, draftsmen needed to prepare surveying and architectural drawings according to a variety of scales. Their work might call for them to reduce life-size conditions in a ...

A protractor is used to draw and measure angles. An angle is the amount of turn between two lines. Angles are measured in degrees with the symbol °. Angles can be labelled with 3 letters (eg DEF) to ...