High lights

Coupling Between Earth-Return Circuits. Induced voltages recorded in communication circuits paralleling d-c electric railways, at times of short circuit on the railway, have shown marked divergencies from computed values. Because of the numerous factors that might contribute to these divergencies, experimental studies of the transient coupling between parallel earth-return circuits, free from the effects of shielding conductors, and with concentrated rather than distributed grounds, have been made in order to provide a better understanding of the problem (pages 1159–64).