KELLOGs (continued) hundredth of a micron, 10th of @ micron - 1 micron, The ordinate is fraction scavenged out of the cloud, in which [th rain cloud and the radioactive naterial have been togethey for one hour, Brownlen notion and turbulent effects have opesated for one hour to bring the particles into the cloud drop e At the end of one hour, rain starts and « moderate rain o, 2.5 millimeters per hour occurs for one hours. Now, the a fali- ing through the cloud - as Langmuir predicts - will scavesge out the cloud droplets quite effectively, the cloud droplets in the order cf 20 or ao. Being So in this region, off the scale, we would Lave something that might correspond to the scavenging of the cloud droplets themselves. Now, this large value corresponds to the scavenging af the radioactive partic directly by the cloud falling raindrops. We have large collection efficiencies for the large radioactive particlbs - as I mentioned, Over here at this end of the curve for very] azall particles ve have a large fraction of the small particles] taken into the cloud droplets, and so when the rein occurs it spavenges them = brings them down in solution. In thie intermediatp region between about a tenth of a micron and 1 micron we are at loss to find any good mechanism for bringing the radioactive material down in rain ~ unleas we imagine that the cloud droplets [and the radioactive rarticles could last together for a matter off a day or more. In this case there might be tins for soz of rac‘ioactive material to be taken into the cloud droplete] A Bere 3/