tances, 1.e., in the region where Machreflection had just started should coincide rath closely with those for the 1-Kt curve. At greater distances one would expect a smoothtt sition toward,the 2-Kt curve as the Mach stem grows until it covers the entire hemis here, It is interesting to note that scaled arrival times derived from measurements over water beh in exactly this fashion. No attempt was made to comparethe curve of peak positi ve over ores: sure vs scaled distance on King shot with a reference standard, since no data were available. from another shot having the same scaled height of burst. The only alternative was a comparison with a height-of-burst chart. As on Mike shot, scaled values of positive-phase duration were compared with free-air curves for 1 and 2 Kt (Fig. 35). It was difficult to predict how these values should have compared, but again it was found that scaled durations were a little longer than would have been expected from a burst of a 2-Kt bombin free air, although not so long as on Mike shot. Positive impulses (Fig. 36) were found to be close to those expected from a 2-Kt burst. Table 8—- RESULTS OF MIKE SHOT REDUCED TO 1 KT (RC) AT SEA LEVEL Distance to Time of Station No. ground zero, ft arrival, sec 615.02 611.01" 611.01t 611.02* 611.02T 613.01* 613.01* 611.04* 611.04T 613.02* 613.02* 612.01* 612.01T USS Estes 376.0 724.7 124.7 976.0 976.0 1673 1673 2168 2168 3413 3413 5207 5207 8455 0.0638 0.240 0.240 0.403 0.403 0.928 0.929 1.335 1.335 2.388 2.388 3.873 3.873 6.71 *Side-on baffle. fPitot static tube. 6.3 Height-of-burst Chart King The scaled distances at which the various peak overpressures occurred on Mike and shots have beenindicated on the height-of-burst chart”” published in TM 23-200 (Fig. 37) by greater means of appropriate symbols. It will be noted that, for pressure levels of 4 psi and zero are ground to interest of level ure overpress the from distances scaled on Mike shot, the of atgreater than would be indicated by the isobars; at lower overpressure levels the effects indicate to seem would on observati This true. be to converse the mospheric refraction cause and that some that perhaps the zero intercepts of the height-of-burst chart should be revised on King of the curves should toe out more than they do. Overpressures measured over water measured on the shot seem to corroborate in generalthe findings on Mike shot, whereas those for thermal applied n correctio the that indication an isobars, land blast line fall very near the effect in constructing the height-of-burst chart had been a valid one. 57