effect by considerin; the greater effect an Integrating time constent, such es ts used in the count rete meter, has on low, pulse heights. ?° suggests itself, No mechanism to explain the former effect however, and the fact that fair acsreement exists in most cases between comparable 60-kev and 280-kev lines leads one to doubt the existence of a consistent energydependent machine effect to explain the discrepancies. It may be that the disagreements are largely due to resolution problems in the low energy region of the standard gain records, since in many cases the areas could be brought closer to agreement by taking from one line and adding to an adjacent line. This problem is especially troublesome in trying to separate the 60, 105, and 140 kev lines on the standard gain records. A discussion of the overall performance of the system in analyzing the standard sources, including the consistency of the results,is found in Appendix I. DISCUSSION It is of special interest to note the presence of Nae activity in both the Zuni and Navaho cloud samples (the only samples to reach this section soon enough for such detection were the cloud samples from each shot). This activity is evident from the 1.37-and 2.75-Mev total absorption peaks detectable on the first two or three recordings made with 25 7