This method of measuring the pressure of liquids and gases is as useful today as when it was invented by a French watchmaker in 1849. It contains a curved metal tube, closed on one end. When the air pressure inside the tube increases, it uncurls, causing a small movement at its closed end, which turns a pointer to show the pressure direct in psi. Includes: 100 mm dial; cast metal base; 3 mounting holes on frame; nozzle on post for connections (3/8" O.D.). Calibrated 0-30" Hg (0-750 mm).
