Steam digester Torricelli and further developed by German scientist Otto von Guericke with his Magdeburg hemispheres. Guerike's demonstration was documented by Gaspar Schott, in a book that was read by Robert Boyle. Boyle and his assistant Robert Hooke improved Guericke's air pump design and built their own. From this, through various experiments, they formulated what is called Boyle's law, which states that the volume of a body of an ideal gas is inversely proportional to its pressure. Soon the ideal gas law was formulated. Based on these concepts in 1679 a Boyle's associate, named Denis Papin, built a "bone digester", which is
Gay-Lussac's law Stanislao Cannizzaro was able to convince the First International Chemical Congress in 1860. This law is often referred to as Gay-Lussac's law of pressure–temperature, between 1800 and 1802, discovered the relationship between the pressure and temperature of a fixed mass of gas kept at a constant volume. Gay Lussac discovered this while building an "air thermometer". The pressure of a gas of fixed mass and fixed volume is directly proportional to the gas's absolute temperature. If a gas's temperature increases, then so does its pressure if the mass and volume of the gas are held constant. The law has a