36 
could not be reached by ship. They were provided with glass 
tubes open on both ends, about 2 cm in diameter and 6 cm liong, 
having a cross-sectional area of 2.5 cm?, These were filled 
with sterile water and closed with caps that fitted over the 
ends of the tubes. To take a sample, the diver removed the 
caps, pushed the tube into the bottom, and then replaced the 
caps. Although a somewhat variable depth of the sediment column 
is taken by this procedure, the entire surface layer is captured, 
and this layer is the significant portion. When the capped 
tubes were returned to the divers’ launch, their entire contents 
were transferred to sterile water blanks of proper volume to 
give an initial dilution of 2.5 em /100 mi of surface area of 
sediment. From this initial dilution, further dilutions of 
ten fold increments were prepared and coliform contents deter= 
mined by Standard Methods. The counts were calculated on the 
basis of MPN's/cm@ surface area of sediment. 
The sampling apparatus used from the VELERO IV is shown in 
Figure 9, A vial of 2.5 cm? cross-sectional area, filled with 
sterile water, is inserted into the vial holder while the 
sampler is in an inverted position. The apparatus is then 
cocked, bringing a metal plate across the mouth of the vial, 
which closes it. The sampleris turned upright, maintaining a 
tension on the cable during this operation, and then lowered 
to the bottom. When the foot of the sampler hits the sediment, 
the plate pulls back allowing the vial to penetrate a cm or two 
into the bottom, depending on the type of sediment. As the 
cable is wound in to retrieve the sample, the plate closes, 
Sealing the sampie in the viai. When the sampler is brought 
