This late 19th Century proposal for an improvement to a vise seems like it could be a useful idea in certain specialized situations, The body of the vice would hold a turret consisting of four jaw types, smooth flat, rough flat and two with V grooves. The bolt would be loosened and the turret rotated to provide the proper jaw. Good thinking, I guess... but someone came up with a simpler and stronger solution by casting V groove pipe jaws below the normal jaws which does most of what this inventor proposes.
The drawing is confused by the bolt and nut in the jaws (presumably in the vertical V groove turret jaw), being used as a hold-down for a random chunk of material.
Text below for those who enjoy the language of 130 years ago.