Sounding machine
‘The numbers tell the tale’ is a saying that also applied on board ships. The depth of water could be determined using a sounding line. The design for this sounding machine was patented by Edward Massey in 1802. The machine was attached to a sounding line. As it sank to the seabed, a rotating vane drove a counter with a wormscrew; its revolutions were converted to the depth in fathoms.