The Prony brake (dynamometer) is named after the inventor Gaspard de Prony. Prony invented ithe Pony brake in Paris in 1821to measure the power of engines.
According to the 1911 version of Encyclopedia Britannica:
PRONY, GASPARD CLAIR FRANCOIS MARIE RICHE DE (17551839), French engineer, was born at Chamelet, in the department of the Rhone, on the 22nd of July 1755, and was educated at the École des Ponts et Chaussées. His Mémoire sur la poussée des vofites published in 1783, in defence of the principles of bridge construction introduced by his master J. R. Perronnet, attracted special attention. The laborious enterprise of drawing up the famous Tables du Cadastre was entrusted to his direction in 1792, and in 1794 he was appointed professor of the mathematical sciences at the École Polytechnique, becoming director at the École des Ponts et Chaussées four years later. He was employed by Napoleon to superintend the engineering operations for protecting the province of Ferrara against the inundations of the P0 and for draining and improving the Pontine Marshes. After the Restoration he was likewise engaged in regulating the course of the Rhone, and in several other important works. He was made a baron in 1828, and a peer in 1835. He died at Asnières (Seine) on the 29th of July 1839.
Gaspard Clair François Marie Riche de Prony
One of de Prony's most important scientific inventions was the 'de Prony brake' which he invented in 1821 to measure the performance of machines and engines.
The Prony Brake is designed to measure the brake horsepower of a motor.