PROF. W. BOTHE in the Zeitschrift für Physik (vol. 59, p. 1) describes a method for registering simultaneous impulses of two Geiger's counters, which depends principally on the working of a two-grid thermionic valve. Lately, I have had the opportunity of experimenting with a circuit which perhaps is simpler and at the same time has the advantage that it can be extended also to the registering of triple simultaneous impulses or even more. The circuit adopted (for triple coinciding impulses) is shown in the accompanying diagram (Fig. 1).