The u-tube manometer has legs of unequal internal diameter d1 and d2, which are partially filled with immiscible liquids of density1, and density2 respectively and which are open to the atmosphere at the top. If an additional small volume of the second liquid is added to the right-hand leg, derive an expression in terms of density1, density2, volume2, diameter1, and diameter 2 to solve for specific gravity. The amount by which the first liquid will fall on the right-hand leg. If density1 is known but density2 is unknown, could the apparatus be used for determing the density of the second liquid?