Atmospheric phenomena—a subject of curiosity and interest from the beginnings of civilization—were first discussed in a systematic manner by Aristotle. Until the Renaissance, however, meteorology remained a field dominated by empirical knowledge mainly regarding the exceptional events occurring above the Earth's surface. Experimental meteorology was inaugurated by the Accademia del Cimento. The invention and improvement of the thermometer, barometer, and hygrometer allowed the transition from simple observation of meteorological phenomena to their measurement and comparison. The 18th C. saw the advent of systematic observations, with the consequent production of meteorological ephemeris, collected by an ever denser network of observatories. With the introduction of very sophisticated and fully comparable instruments in the 19th C., the study of the physical and dynamic properties of the atmosphere became an extremely specialized field.