er
Since the metal Nansen bottles were suspected of absorbing radioactive materials in sea
water, samples were also taken with polyethylene bottles. Inert polyethylene plastic
1-gallon bottles were filled with fresh water, 1 liter of which was squeezed out of each
by compressing the sides of the bottle and then the bottle sealed with a stopper containing
a breakable glass seal.
After being clamped to the hydrographic wire, the plastic bottles
,
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20,
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54
MICROAMPERES
Figure 2.4 Mark I calibration from distant point source of radium, Site Elmer
Rad-Safe compound, 10 May 1954. Microammeter: Western Electric
Mod D~167867, 0-50ua.
were lowered to the sampling depth and then the scals were broken by dropping a messenger. After allowing time deemed sufficient for filling, the bottle was raised to the
surface.
This ingenious trace-element sampling device was proposed for this cruise by John D.
Isaacs who plannedthe field cruise and located mostof the essential hydrographic gear
from accessible facilities.
2.2.2 Samples Collected. Water samples were taken at 24 points along the ship’s
track after Shot 5. Surface samples were taken at 15 points while the ship was underway.
Vertical hydrographic casts were made at the eight numbered stations as indicated
in Figure 2.6. These samples were taken at the following wire depths.
1 cast: 50, 100, 150, 200, 500, and 800 m
4casts: 25, 50, 100, 200, and 500 m
4 casts:
25, 50, 100
22