Each connecting-cord circuit had associated with it a clearing-out drop connected between the cord and earth and a key by means of which the operator's speaking and ringing apparatus could be brought into circuit.
Eurystheus imposed upon Heracles the task of clearing out all his stalls unaided in one day.
The moles use a similar artifice in clearing out the dirt from the cavities they form by scraping.
I'll be clearing out my desk, buying cakes for the office, the whole shebang.
Moreover the clearing-out drop of the cord circuit was replaced by an arrangement which included the provision of one signal to be controlled through the agency of a relay by the calling subscriber, and another to be controlled by the person wanted.