33 



were consistently liigher by about 3 percent than the coefficients given 

 in the P.T.R. certificates. However, there is no assurance that the 

 meter-wheel was accurate. It is therefore uncertain whether or not 

 the pressure coefficients of the thermometers had actually changed by 

 the amount mentioned. In the computations it has been assumed 

 that the coefficients did change and the listed depths of the observa- 

 tions may therefore be too shallow. It is of no consequence in the 

 individual surveys where the same equipment was used at all stations, 

 but would be pertinent in any comparison of these data with data col- 

 lected by other investigators. 



As was indicated in the description of the equipment, the General 

 Greene was outfitted for the determination of the salinity of the 

 sea-water samples by either the electrical conductivity method (salin- 

 ometer), or by the chemical method (silver nitrate titration). The 

 salinometer had originally been designed for use with water in the 

 constant-temperature bath. Subsequently it was changed over to an 

 oil bath, chiefly from considerations of the heating-element problem. 

 Although the vigor and direction of the circulation of the bath medium 

 was satisfactory when water was used, the same circulating system was 

 inadequate after the change to oil had been made. This resulted in 

 an unduly long time being required for the cold sea-water samples to 

 be brought to temperature equilibrium wdth the bath. This fact was 

 not discovered until after the General Greene was in the field where 

 extensive alterations were not possible. Lowering the regulating 

 temperature to a point only slightly above maximum room temp ra- 

 ture, and the addition of a makeshift centrifugal impellor to the existing 

 stirring shaft with the help of the engineer officer, improved the per- 

 formance of the instrument to a point where it would have been feasi- 

 ble to use it. However, as the altered salinometer was still somewhat 

 slower than titration, the latter method was used for routine measure- 

 ments and the salinometer was considered as stand-by equipment. 



The titrations were performed by the oceanographer's assistant, 

 Bernard S. Loebig, yeoman, first-class. Each sample was titrated 

 twice and where the two measurements differed by more than 0.01 %o 

 chlorinity a third determination was made. It is considered that the 

 measurements are accurate to 0.02 %o in salinity. 



The oceanographer made the dynamic calculations at sea as the 

 data were collected. These data and calculations appear in tabular 

 form beginning on page 36. A current map showing the topography 

 of the sea surface with respect to the 1,000 decibar surface has been 

 constructed from the 19 oceanographic stations, no. 14G8 to no. 1486, 

 and is shown in figure 1 1 . Wliere the measurements do not extend to 

 a depth of 1,000 meters a modification of the method of J. P. Jacobsen 

 and Aage J. C. Jensen (Rapports et Proces-Verbaux des Reunions, vol. 



