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experiments run on two succesive days at Whites Point. High coliform 
counts persisted for the full six hours in one instance, and for two 
hours in the other. The chlorinity data show that a high percentage 
of sewage was present in all samples and that the dilution usually 
noted in dye patch experiments did not occur. Further, field obser- 
vations showed that the dye patch, started at the inner boil, was 
reinforced with sewage from the outer boil during the experiment. 
Both of these observations suggested that conditions exist in which 
the expected decrease might not occur. Unfortunately, an accident 
occurred in which the plugs of all the presumptive tubes in these 
experiments were thoroughly wetted with polluted water and contam- 
ination of the lactose broth was possible. Consequently, no reliance 
can be placed on these data. 
From the data, one would predict a one to four magnitude 
isappearance of the surface coliform population in about six 
hours for the types of conditions and types of sewage represented 
in these experiments, Disappearance was most rapid at Orange 
County and least rapid at Whites Point with Hyperion intermediate. 
In terms of per cent reduction, with the boil population taken as 
100%, the values would be 99.98% for Orange County, 99.90% for 
Hyperion, and 90% for Whites Point. Using the coliform count of 
the efflvent being discharged as 100%, the per cent reduction for 
Orange County would be 99.9993%. Since the same type of picture 
was obtained repeatedly at Orange County, it is probable that the 
results are representative; the other curves being based on single 
experiments are only suggestive. 
