22 C. HEDLEY. 



As a contribution to this subject, Dr. H. G. Chapman 

 has kindly handed to me the following observations : — 



"The same constituents are found in all samples of sea water, 

 and practically they are in the same relative proportions every- 

 where. In other words, when the quantities of the salts in any 

 sea water are expressed in percentages of total solids similar figures 

 are obtained for each constituent of the sea water. The total 

 amount of solid matter, however, is subject to much variation. 



"The chemical composition of ocean water off Sydney does not 



differ much from that of ocean water generally. A sample taken 



15*56° 

 off Coogee at a temperature of 22° C. had a specific gravity 



4" 

 of 1*0261. Its solid contents were calculated at 35*2 gm. per kilo. 



of sea water. The total halogens estimated as 19*475 gm. per 



kilo, and the sulphates estimated as SO* were found to be 2 '7 6 



gm. per kilo. x 



"An analysis of a sample taken one foot below the surface about 

 50 metres from the shore at Balmoral Beach, Middle Harbour,, 

 Port Jackson at half tide on the ebb gave the following data: — 



Temperature ... 25° 0. 



15*5° 



Specific gravity ^—^ — 1025. 



Freezing point ... -1*9 C. 



Total solids... ... 34*7 gm. per kilo sea water. 



Halogens as chlorides 19*25 gm. per kilo, sea water. 

 Sulphates as S0 4 ... 2*62 gm. per kilo, sea water. 



"When the sea water stands in a rocky pool on the shore, even 

 if awash with the tide, concentration of the salts occurs. From a 

 pool on the eastern shore of Bradley's Head in which many living- 

 shells, sponges, sea weeds, etc. were present, a sample of water 

 was obtained, yielding the following data: — 



Temperature ... 20° C. 



15*5° 



Specific gravity — - — 1027*3 



2 These figures are calculated from a paper by Mr. C. J. White, Journ. 

 Roy. Soc. N.S. Wales, xli, p. 55, 1907. 



