The rst measurements of the properties of high{pressure gases (e.g. carbon dioxide) were made by Amagat in France in the 1860s and 1870s. He worked in a mine shaft using a mercury manometer in a glass instrument for pressures up to 400 bar (approx 40 MPa). (He actually later improved his design to go to 3200 bar using a hydraulic design.) Estimate the size of the instrument needed (for 400 bar). If you assume the radius of the mercury column was 1cm, what was the weight of the mercury in the instrument?