684 Memoirs of the Indian Museum. [Vol. V, 



on the surface at station 14 to over yo at 5 feet and to nearly io'o at 9 feet 

 depth ; but even at the mouth of the bay we still find a very considerable rise in 

 density as we pass from the surface to the 10-feet depth-level. If now we examine 

 the density contour lines at the three levels — surface, 5 feet and 10 feet depth — 

 shown in plates XXXVIII, XXXIX and XL respectively, we see that there is at 

 all levels, but especially at the 10-feet depth-level, a distinct curvature indicating a 

 slow but steady flow of water into the bay. This is particularly noticeable at the 

 5-10 feet depth-levels, where the inflowing current can be traced throughout the 

 whole length of the bay except in its southerly prolongation near Rambha village. 



This inflowing deep current, after passing through the comparatively narrow 

 channel to the south-east of Samal Island, enters Rambha Bay and flows along 

 the bottom till it strikes the shore in the neighbourhood of Chiriya Island and 

 Ganta Sila, and is then deflected towards the surface. This deflection is well seen 

 in section 4, plate XXXII. On reaching the surface the denser water spreads out 

 and flows over the top of the southern branch of the surface current of low-density 

 water that we saw was coming from the head of the bay, where the streams enter 

 the lake, and in this way we get the formation of the area of low density at a depth 

 of 5 feet, that we found to be present at stations. 



The only feature in the conditions existing during the first part of my observa- 

 tions prior to August 17th, 1919, that remains to be considered is the area of higher 

 density that was found in the southern extremity of the bay near Rambha village 

 at stations 16, 17 and 18. This patch of water appears to lie outside the influence 

 of the circulation of water that was going on in the rest of the bay, and station 18 

 showed particularly clearly an area of raised density on the surface. I attribute the 

 comparatively high densities found in this area to the effects of evaporation ; as 

 Annandale and Kemp have pointed out (loc. cit., p. 11) "in a lagoon of the size and 

 shallowness of the Chilka Lake evaporation must, especially in a tropical climate, be 

 more than considerable and doubtless plays a great part in the phenomena we have 

 been discussing." 



I now pass on to the conditions observed after the occurrence of the storm on 

 August 17th. 



During the time when my observations were made on August 18th, a wind was 

 blowing from the south and south-west and this gradually increased in strength so 

 that I was eventually compelled to discontinue my work. The results obtained are 

 shown in section 3, plate XXXIII, and the first fact that strikes one is that in the 

 centre of the bay extending from station 23 to station 25 and having a depth in the 

 centre of about 6 feet is an area of water having a lowered density — 7-0 and under— 

 and raised temperature — 29'5°C and over. It seems to me that owing to the wind 

 the surface current coming from the southern end of the lake, which we have already 

 studied, is modified, so that instead of dividing into two areas, the whole of the low- 

 density water is now carried in a north-easterly direction across the bay. We have 

 here a condition of affairs very similar to that recorded by Annandale and Kemp in 

 1914 (loc. cit., p. 11) except that in this case the effect on the density of the water is the 



