The concept of the ideal gas law dates from 1834. The ideal gas law is a pre-molecular physics, simplified formula for gases, without consideration of other factors like interactions. The state of a gas is determined in this formula by its pressure, volume, and temperature. This formula is most effective for single unmixed gases at lower pressures, like naturally occurring atmospheric gases in ideal states. The ideal gas law has since been superseded, but historically it was a useful principle. It also provided some tablulation for basic calculation of properties of different classes of gases.