estimated peak counts to dose rate for each of the three naturally occurring components of the total terrestrial gamma radiation field.* These conversion factors are given in Table I. The second method relates the "energy" as defined previously in three energy bands centered on the three above-mentioned photopeaks (E ,, 1.32-1.60 MeV; Ez, 1.62-1.90 MeV; E3, 2.48-2.75 Mev) to dose rate by means of three simultaneous equations: T 0.41 (E3 - 0.60) K 0.10 (Ey - 0.7 Eg - 0.5 E3 - 0.7) U = 0.29 (E2 - 0.06 Ey - 0.93 E3 + 0.50) where T, K, and U are the dose rates in ur/hr from the Th232 series, K4 , and the u238 series respectively. The constants in these equations were first obtained by applying a multiple regression analysis to a large number of field spectra, using the values of K, T, and U calculated from the peak area method. In all three cases the correlation was very good, tiating our methods of estimating peak area. substan- The magnitude of the first coefficient of each equation, however, is dependent on the accuracy of our peak method conversion factors, In the case of the K and T equations, this coefficient can be obtained independently in a manner analogous to that used in obtaining the conversion factors for the peak method. This was done and the values obtained agreed to within 5% with those predicted by the regression analysis. The U coefficient could not be calculated independently due to the significant contribution to the Ep band in the field situation of scattered photons from higher energy gamma rays of the uranium series, Rough estimates of this effect indicate that the coefficient of the U equation obtained from the regression analysis is a reasonable one, This band method has the advantage of being more amenable to routine data analysis procedures and of providing more precise individual determinations of component dose rates. Both the band and peak methods agree very closely on the average. Fallout Gamma Two methods are also used for predicting the dose rate from gamma emitting fallout radionuclides? The first relates the estimated areas of the two prominent fallout peaks at 0.75 Mev (Zr95-Nb95) and 0.51 MeV (Rut93_Rnl93, Ryl06_Rp106 | -4e-