Matteo, an Italian mechanician and natural philosopher of the seventeenth century. He was born at Spoleto, and held a curacy at Rome in 1661, but devoted himself principally to scientific pursuits. As an optician, he is chiefly celebrated for the manufacture of the large object glasses with which Cassini discovered two of Saturn's satellites, and for an attempt to rectify chromatic aberration; and in clock-making, for his invention of the illuminated dial-plate, as well as for an attempt to correct the irregularities of the pendulum, arising from variations of temperature. Campani published in 1678 a work on horology, and on the manufacture of lenses for telescopes. His younger brother Giuseppe was also an ingenious optician.