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



in addition to giving the densities at the temperature in situ in the various sections 

 also given corresponding sections after all densities had been reduced to standard 

 temperature, 25'0°C. In an investigation of the physical conditions of so small an 

 area of water it was expected that it would prove necessary somewhat to reduce 

 the usual intervals between contour lines, and this proved to be correct especially as 

 regards temperatures and I have in places drawn them as close as o - 25°C; but as 

 regards the densities obtained, these were found to differ so widely and in such short 

 distances that as a rule I have given them in 0-5 intervals. 



Annandale and Kemp (loc. cit., p. 5) give the depth of water in Rambha Bay as 

 having a maximum of 8 feet during the dry season, with a rise of 5 to 6 feet during 

 the floods. In September, 1914, the density of water in this area was found tobe 6-5 

 [they give it as 1/0065, distilled water being rooo (loc. cit. p. 8)] and again in Novem- 

 ber of the same year they found the density to be 6 - o, though on this occasion they 

 state that "water of appreciable salinity was, however, not so closely restricted to 

 the southern area (of the lake) for a sample obtained off Kalidai ' gave a reading of 

 1-0035 and others off Barkul l of 1-003. The flood waters had somewhat abated, with 

 the result that the level had decreased and the saline water confined during Septem- 

 ber at the extreme south had spread further north." 



At the time of my visit to the lake the depth of water in the middle of the Bay 

 was 11 feet and during September it rose still higher. On August nth, 1919, a 

 sample of water taken at the surface at Barkuda Island showed a density of 9^29 in 

 situ at a temperature of 29' 9°C or of 1078 at standard temperature. 



Throughout the whole period between August nth and December 16th, 1919, 

 there seems to have been a steady fall in the density of the surface layers (vide 

 Appendix, Table II), and a sample taken near Breakfast Island on this latter date 

 and sent to me for examination gave a density at standard temperature of only 2'i9. 

 Allowing for such annual variations as are bound to occur owing to variations in the 

 annual rainfall, my results up to this point seem to agree fairly well with those 

 obtained by Annandale and Kemp in 191 4. It was, however, found that the surface 

 conditions of the water in the bay in August were by no means constant. In plate 

 XXXVIII I have given the densities of the various water-samples taken at the surface 

 at the temperatures that existed in situ, and it shows very clearly the way in which 

 the density decreases as we pass from the mouth of the bay between Barkuda and 

 Chiriya Islands in a south-westerly direction towards the village of Rambha, situated 

 a the head of the bay to which it gives its name. This distribution of the water in 

 the bay in 1919, is the exact opposite of that found by Annandale and Kemp in 

 November, 1914, who record (loc. cit. p. 10) that "throughout the southern part of the 

 lake the water in the middle was of lower specific gravity than that nearer the shores." 

 During the period of my observations between August nth and 18th, 1919, surface- 



1 As neither Kalidai or Barkul are shown on my charts I may mention that the former is an island 

 some 8 miles away to the north-east of the entrance to Rambha Bay, while the latter lies on the main- 

 land about 2 miles to the north of Kalidai. 



