The density of mercury changes approximately linearly with temperature as Hg = 851.5 - 0.086 T lbm/ft3 T in degrees Fahrenheit so the same pressure difference will result in a manometer reading that is influenced by temperature. If a pressure difference of 14.7 lbf/in 2 is measured in the summer at 95 F and in the winter at 5 F, what is the difference in column height between the two measurements?