reserved for the collection of samples to be frozen for the later de- 

 termination of nitrate, nitrite, silicate, and phosphate content by the 

 Woods Hole Oceanographic Institution. Upon return to Woods 

 Hole, the Wenner bridge was completely overhauled and restandard- 

 ized. 



Two samples each for salinity were drawn and stored in polyethylene 

 bottles for the 300 meters and 400 meters depths at station 8365 and 

 all depths from station 8366 to the end of the postseason survey. In 

 September the paired samples were run on both the Coast Guard 

 Wenner bridge and the inductive salinometer, all samples being at a 

 room temperature of approximately 25° C. One polyethylene bottle 

 did not hold sufficient water for measurements to be made on both the 

 Wenner bridge and the inductive salinometer so that the comparisons 

 of salinities between both instruments were based entirely on samples 

 of the same water stored in different bottles. Both instruments were 

 standardized with the same carboy water and on this basis the induc- 

 tive salinometer averaged 0.0035°/oo lower than the Wenner bridge 

 and had a standard deviation of 0.019%o. Thus with the samples 

 apparently at temperatiu-e equilibrium and a relatively warm room 

 temperature the performance of the inductive salinometer was far 

 superior to that when at sea on the Evergreen. Samples that were loo 

 fresh for the Wenner bridge (excluding two relatively fresh samples 

 that were measured on the Woods Hole Oceanographic Institutions 

 Wenner bridge) were measured on the inductive salinometer. The 

 values of salinity for the remainder of the samples stored in poly- 

 ethylene bottles were determined by averaging the values obtained 

 from both the Wenner bridge and the inductive salinometer. 



Sea water stored in polyethylene bottles such as those used by this 

 unit undergoes changes arising from the permeability of the poly- 

 ethjdene walls. R. A. Cox (1954),^ using pure water, has shown poly- 

 ethylene to be permeable to water, whereas V. Romano vsky (1954),^ 

 using sea water, indicated that the permeability was to the solution. 

 A third point of view is that under field conditions the exterior of the 

 bottle would become contaminated with salt water; these salts on the 

 exterior of the bottle, under conditions of a high relative humidity, 

 might create an osmotic effect which could result in either a concentra- 

 tion or a dilution of the sample inside. In the absence of more def- 

 inite information and in the light of observations by Cox and Roman- 

 ovsky, we consider that mean changes in the salinity of our samples 

 stored in polyethylene bottles were of the order of twice the variation 

 between the pair of samples measured at the end of the 2 months, 

 storage period. Since the standard deviation of the pairs is ± 0.019°/oo 



■ Roland A. Cox, Water Transmission of Polythene Bottles, Journal Du Conseil International Pour 

 L' Exploration De La Mer, Vol. XIX, No. 3, 1954, 19, p. 297-300. 



3 V. Romanovsky, Conservation Des Echantillons D'Eau De Mer Dans Des Flacons En Polyethylene, 

 Travaux Du Centre De Recherches Et D' Etudes Oceanographiques, Vol. 1, No. 12, December 1954, p. 1-3. 



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