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
Potential temperature Potential temperature The potential temperature of a parcel of fluid at pressure formula_1 is the temperature that the parcel would attain if adiabatically brought to a standard reference pressure formula_2, usually 1000 millibars. The potential temperature is denoted formula_3 and, for a gas well-approximated as ideal, is given by where formula_5 is the current absolute temperature (in K) of the parcel, formula_6 is the gas constant of air, and formula_7 is the specific heat capacity at a constant pressure. formula_8 for air (meteorology). The concept of potential temperature applies to any stratified fluid. It is most frequently used in the