RADIATIVE HEAT TRANSFER IN HEATED AIR**Chapter 3 is by S. S. PENNER and J. C. STEWART.††A first draft of this chapter was prepared by S. S. Penner. The chapter was then extensively rewritten and revised by J. C. Stewart. It should be noted that the discussion in Sections 3–1 and 3–2 duplicates some of the analysis presented in Section 2–2. However, the point of view is somewhat different and, furthermore, the presentation is now completely self-contained and should allow reading of Chapter 3 without reference to the contents of Chapters 1 and 2.