Mirror (Sydney) 31 Aug. 8/2: Every confidence man ‘travels’ with all sorts of traps for the mugs. There is the ‘derwent’ pot, the ‘slithery,’ the top-sider, and the ‘rail-way.’ These are specially prepared pots, or dice boxes, which a skilful manipulator uses at his discretion.at Derwent pot (n.) under Derwent, n.