Philbert Maurice d'Ocagne

He founded the field of nomography, the graphic computation of algebraic equations, on charts that he called nomograms.

[1] Starting in 1885, he served for six years as an engineer, supporting waterworks projects in Rochefort and Cherbourg and then worked at Seine-et-Oise at the residence of Pontoise.

Ten years later, he became chief of maps and plans and precision instruments for the Ministry of Public Works.

During WWI, his techniques for finding approximate solutions to the transcendental equations of plastic deformation allowed French gunmakers to implement autofrettage on an industrial scale and boost the output of artillery pieces.

[1] Mortimer d'Ocagne, Maurice's father, published widely on economic and financial topics and wrote a book on French higher education: Les Grandes Ecoles de France.