The author presents a new analytic model of the chemical evolution of the galaxy. Explicit solutions for a gas mass, star mass, metallicity, and radiochronometers are obtained for models with parametrized galactic infall, and for which the star formation rate is proportional to the gas mass. Because all physically interesting observables have a simple explicit dependence on the parameters which themselves map a wide space of physical possibilites, the author suggests adopting this model as a reference standard for studies of chemical evolution.