Mercury is to be evaporated at 317°C in a furnace. The mercury flows through a 25.4-mm 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 20 cm × 20 cm The furnace is made of brick having an emissivity of 0.85, and its walls are maintained uniformly at 977°C. If the convection heat transfer coefficient on the inside of the tube is 2.8 kW/m² K 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.