Avogadro's law "P" are taken at standard conditions for temperature and pressure (STP), then "k"'=1/"n", where "n" is Loschmidt constant. Avogadro's hypothesis (as it was known originally) was formulated in the same spirit of earlier empirical gas laws like Boyle's law (1662), Charles's law (1787) and Gay-Lussac's law (1808). The hypothesis was first published by Amadeo Avogadro in 1811, and reconciled Dalton atomic theory with the "incompatible" idea of Joseph Louis Gay-Lussac that some gases were composite of different fundamental substances (molecules) in integer proportions. In 1814, independently from Avogadro, André-Marie Ampère published the same law with similar conclusions. As Ampère was
Kinetic theory of gases "K": This is a first non-trivial result of the kinetic theory because it relates pressure, a macroscopic property, to the (translational) kinetic energy of the molecules formula_12, which is a microscopic property. Rewriting the above result for the pressure as formula_13, we may combine it with the ideal gas law where formula_14 is the Boltzmann constant and formula_15 the absolute temperature defined by the ideal gas law, to obtain which leads to simplified expression of the average kinetic energy per molecule, The kinetic energy of the system is N times that of a molecule, namely formula_18. Then the temperature formula_15