An amplifying device enables operator to be heard for 3 miles and to guide ships into berth.
Item title reads - Another wireless wonder. Ships guided to berths by wireless voice - amplifying device. Though operator spoke in ordinary tones, he could be heard for over 3 miles. Southampton, Hampshire.
M/S of a man looking at a wireless. M/S of the mast and exterior of the ship, the camera pans up and across to a giant speaker shaped a bit like a megaphone.