(4) Thruout the whole cloud, all radioactive particles are of the sane aise, am fall at 50,000 f& per hour, - (eo) In each layer, the central particle falls, without diffusion, ce directed by the winds, witle other partieles diffuse horiaotally away from the center equally in all directions so that, when the layer arrives om the surface, the distribution about the conter is zivon by veiot 2 ” 2 where p = $0.45, a2 r/a,, 3 = total horisontal distance travelled by the Seo central particle, So 35.2 48.. horisontal distance beck to & (The last quantity my be rictured th Metitious point source of the cloud Layer). (£) The dose rate et any point is proportional to tho sum of the concentrations from all of the layers as estimated from tho procecing ormila. bo ‘part from the assumption of a single partiels sise this formlatic has a rember of other obvicus defects, e174 a. The sum of the quantities Coa? should be made proportional to the total radicactive yleld of the"bomb." In practice, the final ceotinates were adjusted sanowhat on account of expected yield. This, in effect, allowed for the influence on C,, tut not on a. be The estimation of S$ as total unsatisfactory in local, fcreezsting wiere tho at meh greater than the heizht of the eloud. distance ig rather dimensions are not elso, there was no tims to find cut whether better results could be Obtained by ehedee cf some cthar values for parameters such as rato of fall for the particles. From the test of the method asainst the Bikini patterns, it we clear that it was good encuzh for the purpose at hend. qt that differenses between foreeast ond actual winds would to to produee much larger errors than those inheront in the cssumrticns. S. Tl apriication, the sethod is not as tedicus as alcht aproar. The standard hodograph plot, ziving the loeation of central perticles falling et §,000 f% per hour, is prepared for the Camand Briefing as 4 matter of course. It can be superimposed on a ten times magnified atoll map, allowing for the 50,000 ft per hour fal) rate aseumed in the meth. “ith a suler of corresponding scale, the distances $, along the siz-tag path to eash of the height points on the hodograph ean be quickly moasured or DakG