This circuit was found in an ancient American documentation. The power supply is not given, but we have the voltages used. The relay is sensitive type for high voltage.
This simple rhythmic light for incandescent lamps was found in old English documentation....
In the figure we show how to obtain a stabilized voltage for the filament of a 6.3 V x 100 mA...
Found elsewhere in this section, but from other sources, this circuit is from Motorola...