Mercury is to be evaporated at 605°F in a furnace. The mercury flows through a 1-in. BWG no. 18 gauge 304 stainless-steel tube that is placed in the center of the furnace. The furnace cross section perpendicular to the tube axis is a square 8 in. x 8 in. The furnace is made of brick having an emissivity of 0.85, and its walls are maintained uniformly at 1800°F. If the convection heat transfer coefficient on the inside of the tube is 500 Btu/h ft2 °F and the emissivity of the outer surface of the tube is 0.60, calculate the rate of heat transfer per foot of tube, neglecting convection within the furnace.