Darlington and Cauer have described a useful way of synthesizing a lossless two-terminal-pair network from a single driving-point impedance and a knowledge of the zeros of transmission. The procedure involved has a good deal of similarity to the Brune process of synthesis, and can readily be extended to RL and RC networks provided the zeros of transmission are restricted to the negative real axis of the complex frequency plane. Although such an extension is obvious, it seems worth while to point out the details involved and to illustrate these with a numerical example.