He also took an interest in physics and was involved in debates with Alessandro Volta on the origin of hail.
He also argued against the ideas of Paolo Beltrami to prevent hailstones with cannons.
Bellani noted that thermometers had problems with the stability of their zero point (0°C as marked by placing in ice) due to defects in their construction and the quality of glass used.
[1][failed verification] In 1820 Bellani invented a device for measuring evaporation that was called an atmometer.
He also wrote on the trails of meteors suggesting that they might remain at high altitude due to the lack of movement of the upper atmosphere.