For times longer than one day, the results are [4] a(t) =~ 5.2 x 107° dé! 2 sec and 38(t) +r(t) =~ (3.9 d7!e2 + 11.7 a7! +4) x 1076 Mev/sec. [5] These results, which apparently are the source of the t7}-2 "law, “ suggest that there should not be a simple power-law dependence of the external gamma-exposure rate as a function of time and that t “1.4 might have been a better “law” over longer times. Nevertheless, the t -1.2 approximation was frequently used to describe the decrease with time of the external gamma-exposure rate. As an approximation, it was then a natural extension to calculate an infinite exposure (IE) as re = a(iy f emt2ut = 8D fe? | = 5R(1)aO°? a where a is the time of arrival. the t" °. [6] In such a calculation, the validity of 1.2 approximation is of major importance. If, for example, a more appropriate model were rl-4 » the infinite exposure would be R(1)ao"4 70.4, For an arrival time of 3 hr, the two models differ by a factor of 4.0/1.6 or 2.5. Recent analysis of the original data taken following the weapons test HARRY (May 19, 1953) indicates that a more appropriate model of the rate of decrease of the external gamma exposure rate is 7}-35 over periods of about 100 hr (Qu81). Hicks (Hi82) has also performed detailed calculations of the expected rate of decay of the HARRY and 206