14 FREILING, CROCKER, AND ADAMS RMS DISPLACEMENT (,) io" 1.0 10 104 T LY / “ww = 107° 10° “A 104 / Nat in Na,O * CaO + 4510, (REF. 13) | — 106 FE Ca** in 2CaO « Al,03° 2510, — (REF. 11) Y x2 a me a Nb(V) in 2CaO* Al,O3 . 25102 1o-7 LK sC(REF..*12) —_ = = ~~ 10-8 . . Sb in CoO(23.3%) — Al,O4( 14.7%) — SiO,(62.0%) (REF. 14) ke y < 107° 0.4 0.5 | 0.6 (1400°C) 1000/ T (T in®K) | 9.7 oe rv x < 0.8 Fig. 7—Some experimental values of diffusion coefficients in molten silicates compared with the values necessary to achieve various root- mean-square displacements in given times.14~!4 to previously under various conditions. At a temperature of 1400°C, a fireball from a 10-kt device would cool about 100°C in a second, and equilibration would never catch up to the falling temperature. For a 10-Mt burst (which is more in the high-yield range for which the treatment was originally designed), the temperature would fall only about 10°C, and the approximation is much more realistic, if still not en- tirely satisfactory. It should not be surprising, then, if the accuracy of