Francesco Siacci

Francesco Siacci (1839 to 1907) was an Italian mathematician, ballistician and army officer, born in Rome. He graduated from the University of Rome in 1860, taught mechanics and then ballistics at the Military Academy and artillery school in Turin, and retired from the army as a major general in 1892. He held chairs of mechanics at the University of Turin and later the University of Naples, and served as an Italian senator from 1893. He is best known for exterior ballistics: his 1888 treatise Balistica and Siacci's method for calculating bullet trajectories at small departure angles were widely used into the First World War. In mechanics he gave Siacci's theorem, which resolves a particle's acceleration into radial and tangential components. He died in Naples.