History of chemistry 1808, certain of his central ideas were soon adopted by most chemists. However, uncertainty persisted for half a century about how atomic theory was to be configured and applied to concrete situations; chemists in different countries developed several different incompatible atomistic systems. A paper that suggested a way out of this difficult situation was published as early as 1811 by the Italian physicist Amedeo Avogadro (1776-1856), who hypothesized that equal volumes of gases at the same temperature and pressure contain equal numbers of molecules, from which it followed that relative molecular weights of any two gases are the same as
Potential temperature 1st law simplifies to: For approximately ideal gases, such as the dry air in the Earth's atmosphere, the equation of state, formula_18 can be substituted into the 1st law yielding, after some rearrangement: where the formula_20 was used and both terms were divided by the product formula_21 Integrating yields: and solving for formula_23, the temperature a parcel would acquire if moved adiabatically to the pressure level formula_24, you get: The potential virtual temperature formula_26, defined by is the theoretical potential temperature of the dry air which would have the same density as the humid air at a standard pressure P.