Atwo liquid double column enlarged-erids manometer is used to measure pressure difference between two points. the basins are partially filled with liquid of specific gravity 0.75 and the lower portion of u fube is filled with mercury of specific gravity 13.6. the diameter of the basin is 20 times higher than that of the u-tube, find the pressure difference if the u tube reading is 25 mm and the liquid in the pipe has a specific weight of 0.475 n/m2