General studies : November, 1967 / by John C. Ayers, Joseph C. K. Huang.

19

the highest concentration noted during each pass was recorded
and used in dilution computations, to obtain the most conservative
dilution figures.
The regular station for the setting of dye patches was in
11-12 feet of water, between the two sand bars, about 500 feet
from water's edge, and off the north side of the plant property.
We have no reason to think that dilution figures obtained off
other parts of the plant property would be significantly different
from those presented here (Table 2).
In Table 2 the incremental dilution between two successive
passes through a dye patch was obtained by dividing the earlier
dye concentration by the later. Cumulative dilution was obtained
by progressive multiplication of the incremental dilutions. After
each multiplication the product was rounded to the nearest whole
number before the next multiplication.
In the dye dilution experiments deliberate effort was exerted
to run experiments on the calmest days possible, for low wind and
minimum wave action produce least mixing and dilution, hence giving
"worst condition" figures for dilution. Effort was also directed
to obtaining observations under winds from as many directions as
possible. The experiment of 19 September was carried out because
of our desire to see an offshore wind, not because the wind
velocity was in the desirable range.
On 19 September the dye patch was estimated to be 0.9 mile
southwest of the regular setting station when the two closelyspaced measurements were obtained. A loose connection in the
fluorometer prevented earlier measurements, and developing seas