will fall first, near the explosion, Lighter ones will be carried on winds, hundreds or perhaps thousands of miles, naturally from the force of gravity, before settling to the ground or more rapidly should they become mixed in a weather front and be brought down in a rainfall. aenerally referred to as "local fallout.” am} lands within a few hours, or days. that is, isotopes of many kinds, l.e., This is what is It is heavily radioactive in nature It contains "mixed fission products"--~strontium, cesiun, iodine, giving off beta and qamma radiations of different energies. zinc, cobalt, Generally this local fallout can be seen in a cigar-shnaped pattern, with the lightest activity at the outer edges and the heaviest toward the center. Not all of the fallout, however, days, comes down in the first few hours or This is the material which has heen injected into the stratosphere (a zone bheqinning at ahout 40,000 feet), The particles which have ascendea to this height and above in the towering cloud are verv fine and light, particles of smoke. lire These radioactive particles will he circulated about in the stratosphere--which rarely has clouds and in which the temperature is relatively constant--until it has spread out all over the earth. This Material will take months and years before it has returned to the earth's Surface, The radioactivity, which may be soread throughout the world more or less uniformlv, will return to the earth in the same manner, although it is possible that some areas of the world will receive heavier amounts of this fallout than others. How this radinactivity, once it has returned to the earth, comes to he consumed and retained by man is due to one of the unicue properties of radioactive materials. 1O14b22 “