Lorenzo Mascheroni (1750-1800) was an Italian mathematician and physicist. In 1797, he published *La Geometria del Compasso,* in which he proved that all Euclidean constructions can be accomplished using only a compass. Mascheroni dedicated this book to Napoleon Bonaparte, who, he knew, possessed an interest in geometry.

One of Mascheroni’s constructions with its accompanying diagram:

*The images above are provided courtesy of Columbia University Libraries, George Arthur Plimpton Collection.*