aaptae tn at all points in the shaded portion of the foxhole between 1 and 3 ft from the top, if the diffuse-reflection coefficient of the wall surfaces is one third or more and at least 1 ft of the back wall is exposed to direct thermal radiation. z “* 5 Ly 2. _ When the thermal radiation is incident end-on (2-#t side), - the thermal flux is equal to 10 to 35 per cent of the above-ground value -at all points in the shaded portion of the foxhole between 2 and 3 ft ~ grom the top, if the diffuse-reflection coefficient of the wall surface is one third or more and at least 2 ft of the back wall is exposed to direct thermal radiation. 3. Caution must be used in the prediction of the thermal-radiant exposure in a foxhole, since there are a significant mumber of instances for which the radiant exposure is not proportional to the amount of wall exposed, or does not decrease with depth in the foxhole or does not decrease with distance from the exposed wall. kh, For a 5 per cent or greater thermal-transmission value for foxholes and bomb yields >230 KT, there is a range of slant distances in which there is a 50 per cent probability qf immediate casualties attributable to thermal-radiation burns, while only minimal injuries are anticipated pecause of the initial nuclear radiation (200 rem or less) and overpressure (moderate damage or less to foxholes). In the instance of a 10 per cent thermal-transmission value for foxholes, this same conclusion holds for bomb yields >) 37 kr.