An atmospheric analysis of the cool white dwarfs which show atomic metal lines in their spectra is carried out. New spectroscopic observations of five white dwarfs were obtained at Kitt Peak with the 84-inch (213 cm) telescope. Three of these stars show sufficiently strong metal lines to carry out abundance determinations. Nongray model atmospheres are computed for three of these stars which are consistent with the observed AI , r, the Chandrasekhar mass-radins relation, and G - I or V - r colors. The influence of convection is included and a temperature-correction procedure is described. Line profiles are computed by using the impact approximation with the (6,12) Lennard-Jones potential to describe the interaction. The main result is that the atmospheres of the cool white dwarfs are found to be nearly pure He. The metal and hydrogen abundances are found to be of the order of 10- and 10- by number, respectively.