An air-filled, hemispherical shell is attached to the ocean floor at a depth of 10 m as...

An air-filled, hemispherical shell is attached to the ocean floor at a depth of 10 m as shown in Fig. P2.25. A mercury barometer located inside the shell reads 765 mm Hg, and a mercury U-tube manometer designed to give the outside water pressure indicates a differential reading of 735 mm Hg as illustrated. Based on these data what is the atmospheric pressure at the ocean surface?