3a 1‐in‐od steel tube has its outside wall surface maintained at 250 f. it is proposed to increase the rate of heat transfer by adding fins of 3/32‐in thickness and 3/4‐in long to the outside tube surface. compare the increase in heat transfer achieved by adding 12 longitudinal straight fins or circular fins with the same total surface area as the 12 longitudinal fins. the surrounding air is at 80 f, and the convective heat‐transfer coefficient is 6 btu/h ft2 f.