the values ofE,* were taken from the literature, disregarding the ionic strength originally used. 1 don't think this invalidates the proposal the paper contains. Daniel Rodrigues de Moura Universidad Federal de Minas Gerais Belo Horizonte, MG, Brazil
Solving Quadratic Equations To the Editor:
In a recent issue, Brown [1990,67,4091 pointed out that the solution of the quadratic equation (1) ax2+&+e=0 bv the standard formula
does not work well if the absolute value of 4ac is much smaller than b2 because one of the roots then is a small difference between large numbers. For such cases he suggests a different formula. However, for 14acl
