"A type of receiver has come into wide use as a result, which is commonly called the _direct-current receiver_, deriving its name from the fact that it employs the direct current that is flowing in the common-battery line to magnetize the receiver cores."
"In order that they may have both of their hands free to set up and take down the connections and to perform all of the switching operations required, a special form of receiver is employed for this purpose, which is worn as a part of a head-gear and is commonly termed a _head receiver_."
"Needs to use his hands with more force in attempts to press and jam before the receiver is able to get into the route ..."