mate of the total activity is made by rotating the profile about its vertical axis through 2 7 radians and integrating. Table 4.1 gives these estimates and compares themwith the theoretical estimatesof cloud activity given in Table 1.1. Except for the 15-minute Zuni cloud, estimations, based on rocket data, of the total number of photons in the clouds were not influenced by theoretical estimates. Even so, the results agreed closely. The uncertainties involving such items as energy of the photons, axial symmetry of the clouds, and positions of rockets are such that the close agreement might be fortui- tous, but it may be concluded that the theoretical values and those derived from rocket data agree, at least, in order of magnitude. 4.3 CONTAMINATION OF THE ROCKET The possible contamination of the rocket itself was considered important since it would affect the measurements obtained by the radiation transducer. At the velocities attained by the rocket, aerodynamic heating causes the paint to burn off the skin of the rocket, leaving 2 blackened, charred surface. Subsequent contamination of this surface could cause high background detection in the rocket head. However, examination of the data obtained revealed background counting rates abcve 6 percent in terms of the peak readings in only four cases and in these cases the peak readings were relatively low. These tour sets of data were corrected (see Section 3.2) for contamination of the rocket; however, even if they had not been, the resulting cloud profiles would not have been Significantly altered. 35