This patent was not for a whole lathe - but for an unusual' slide rest' intended to be adaptable to lathes by other manufacturers. Resembling at a glance the type of 'combined lathe attachment' by makers such as Clement, the device had been granted patent 12,423 on February 20th 1855 - this text is shown towards the bottom of the page.
The fitting was designed to be both a slide rest for turning and a tailstock - with the tailstock's screw-fed spindle capable of being fitted with either a centre to hold between-centres work or a turning tool. When employed in the latter state, the only longitudinal travel available was that provided by the tailstock spindle, at a guess around one-and-a-half inches, which was sufficient for the sort of work undertaken on this class of lathe. Facing off was possible by slackening the assembly and using a screwed rod (N in the drawing) to rock the tool backwards and forwards.
William Stephens also secured another patent - 16,811, granted on March 10th 1857 - for a simple 2-jaw chuck; the patent document is shown at the bottom of the page.