"Temperat-ures at a depth of l6h feet (50 meters) were "based 

 only on "bathythermograms . These data are less numerous than for 

 surface temperatures "because much of the area of the Gulf is 

 shallower than l6k feet and also "because many of the lowerings made 

 in the rest of the area were too shallow. Temperatures at l6h feet 

 were less than T0° in the Ara"bian Sea, Increasing to more than 80° 

 In the Strait of Hormuz. "Values again decreased from the strait to 

 as low as 67.2° within the Persian Gulf. The latter temperatures 

 are lower than those of water found at any depth in the strait, so 

 they pro"ba"bly mark the position of patches of "bottom water remaining 

 after the previous winter. 



"SALINITY 



"During the two-week stay in the Persian Gulf and the Gulf of 

 Oman, samples of the surface water were collected at 122 stations 

 for salinity determinations . At eighteen of these stations vertical 

 series of water samples were also o"btalned, usually from depths of 

 66, l6h, and 328 feet (20, 50, and 100 meters) . All of the water 

 samples were titrated for chloride content, from which total salinity 

 was computed. 



"Results of the salinity measurements are shown in Figure IV- 2 . 

 Some of the irregularity of the isohalines results from the use of 

 water samples collected a few days apart "by different ships. Surface 

 salinity increased from ahout 36.5^ ... in the middle of the Gulf 

 of Oman to values higher than U2.0X0 in the Persian Gulf. The main 

 surface salinity gradient was transverse to the Persian Gulf, with 

 salinities of less than 38 -OX" common on the northeastern side, in- 

 creasing to more than 4l.O^ on the southwestern side. The greatest 

 salinities of all, k2.h/L, occured in Kuwait and Bahrein "bays, where 

 water circulation is impeded. It is interesting to note that the 

 salinity off the delta at the head of the Gulf was ahout 38. 0^, 

 greater than the salinity along most of the northeastern side of the 

 Gulf. Thus, It appears that the discharge of fresh river water was 

 small during this period. 



"The vertical series of salinity determinations show that with- 

 in the Persian Gulf, salinity consistently increased with depth. 

 The value at l6k feet was ahout ^0.0^= along the northeastern side 

 and a"bout ^1.0|o along the axis of the Gulf. In the Gulf of Oman 

 salinity remained more nearly constant with depth, and in one series 

 even decreased with depth. The lowest salinity obtained in the re- 

 gion was 35.5^ at a depth of 672 feet (200 meters) in the Gulf of 

 Oman. 



"Only three earlier sets of salinity measurements from the 

 Persian Gulf could "be found. Two sets were taken "by German steam- 

 ships. One of these, covering the period Fe"b3ruary, May, and June, 



39 



