Volume Eleven - Pre-Victorian to the Present Day - some more aspects - The Steam Navvy and the Dock Extension of 1883 . . .

After the machine has dug out all within reach, the jack screws which steady it are eased, and the propelling gear being put in action, it is moved forwards 3 ft. or 4 ft. ; the screws are then tightened down, and another series of cuts is commenced. The cuts all radiate from the centre round which the jib swings ; and they may together form a hole more or less resembling a crater, according to the plan adopted in making the excavation.

A trade magazine advertisement for the 'Dunbar & Ruston's Patent Steam Navvy.'