Pipes, How to clear, [164]
Plants as a source of water, [134], [135]
Plattner process, [94]
Plummer blocks, Cleaning greasy, [163]
Pollok process, [95]
Power for mills, [147]
Prospect, First, [29];
Determining value of, [29], [30], [31]
Puddlers, [153-155]