with values up to 34-0 o/oo occurred toward the west and extended as a 

 tongue eastward. The values toward the China Sea were near 33 • 4 o/qq. 

 There is no indication of low salinity water entering from the China Sea, 

 except at one station, where a value of 32 -840/00 was found. This is 

 in great contrast to conditions found during the south-west monsoon. 



At 50 Metres (Chart 19) . — At this level most of the water has a salinity 

 of about 34-0o/oo- A number of centres with lower values, down to 

 33-6 0/00 or 33-40/00, occurred in various areas. 



At 75 Metres (Chart 20) .—At this level the salinity is 34-2 0/00 to 

 34'3°/oo or slightly higher throughout most of the sea. Lower values 

 were found to the south, and more especially to the west and along 

 Palawan, where values as low as 33-7 0/00 were found at two stations. 



At 100 Metres (Chart 21).— At this level the salinity distribution 

 resembles that at 75 metres. There is a great uniformity of the water, 

 with values mostly between 34 • 3 0/00 and 34 - 4 o/qq, except along Palawan 

 where the saUnity is lower ; close to 34-0 0/00 . 



At 200 Metres (Chart 22). — At this level the horizontal distribution 

 of salinity is practically uniform. The extreme range of salinity at this 

 level is 0-09 o/oo- In Chart 22 the contour interval is only 0-04 o/qq. 

 It will be noted that the salinity is everywhere close to 34-4 o/oq. 



Below the 200-metre level the salinity is extremely uniform with values 

 between 34-4 o/o^ and 34-5 o/oo- 



Salinity : South-west Monsoon 



At the Surface (Chart 23). — During the June-July survey the salinity 

 at the surface throughout the central and eastern parts of the sea was 

 between 34 - 0/00 and 34 - 2 ^joo. This is in contrast to much lower 

 values found here during the previous survey when the salinity over the 

 entire Sulu Sea was less than 34 - o/oo- The significance of this difference 

 in salinity is discussed below. 



Another prominent feature of the distribution of surface salinities 

 during the June-July survey is the obvious effect of an influx of water 

 from the China Sea. Salinities in the China Sea west of Balabac Strait 

 were about 32 - o/oo- The effect of the influx of this water into the Sulu 

 Sea can be seen almost half way to Zamboanga in the fan-shaped pattern 

 of increase in salinity eastward. The pattern also indicates a division 

 of the China Sea water into a northward flowing branch along the coast 

 of Palawan and a southward branch. 



At 50 Metres (Chart 24). — At this level the salinity is very uniform 

 compared to the salinity at the surface at this season or at the same 

 level during the north-east monsoon. All values are close to 34-2 "/oo or 

 34-3 %o, except at Balabac Strait, where 34-0 °/oo was found at one 

 station. Apparently the influx of water from the South China Sea is 

 limited to a shallow layer less than 50 metres in thickness at this season. 



At 75 Metres (Chart 25). — At this depth the sahnities are as uniform 

 as at the 50-metre level with values close to 34-3 "/oo and 34-4 %o. This, 

 again, is in contrast to conditions at this level during the north-east 

 monsoon surveys, when lower values were found (about 33-6 °/oo) at 

 stations along the coast of Palawan (Chart 20). 



248 



