The discovery of the principle of the barometer which has perpetuated his fame ("Torricellian tube" "Torricellian vacuum") was made in 1643.
He also wrote an Essay touching the Gravitation or Nongravitation of Fluid Bodies (1673); Difficiles Nugae, or Observations touching the Torricellian Experiment, &c. (1675); and a translation of the Life of Pomponius Atticus, by Cornelius Nepos (1677).
Lampadius, however, showed that there was no phosphorescence in a Torricellian vacuum; and other experimenters proved that oxygen was essential to the process.
In 1800 he became a secretary of the society, and in the following year he presented the important paper or series of papers, entitled "Experimental Essays on the constitution of mixed gases; on the force of steam or vapour of water and other liquids in different temperatures, both in Torricellian vacuum and in air; on evaporation; and on the expansion of gases by heat."
The former determination is made by driving out the dissolved gases from solution and collecting them in a Torricellian vacuum, where the volume is measured after the carbonic acid has been removed.