Corrections [Physics Today, v. 31(2), p. 84)

November 1977, page 34, figure 3—The labels on the two blue curves, "Silicon avalanche photodiode, 0.82 microns" and "Silicon photodiode, 0.82 microns," should be interchanged. November, page 63, third paragraph, line 9 up—line should read "gases, so that the higher transport to, and…" The editorial revision implied that krypton and xenon have a higher transport to, and deposition in, the human lung, whereas it is rather uranium, thorium and daughters in coal that have higher transport and deposition. Page 63, fourth paragraph, line 7—line should read "…comparable in order to make the…" The editorial substitution of "to coal hazards" makes the sentence erroneous. It is the radioactive hazards that are very roughly comparable, not the total hazards. It is the thrust of the author's findings that the total hazard of coal is orders of magnitude greater than that of fission. December, page 26, column 3, lines 27/28—for "considerable stress" read "considerable success."