HTDROGRAPBY IX PASSAMAQVODDY BAY 299 



SESSIONAL PAPER No. 38a 



substances, takes up all that it can dissolve and carries it down into the ocean and, 

 though the quantity of a substance which goes into solution may be comparatively 

 small, we understand how it is that the sea contains such diverse elements. 



The two predominant elements which are found in the water of the sea are chlorine 

 and sodium. It seems logical to admit that the sea was always salt since we find in 

 the ocean of to-day certain shells which require a definite salinity and which were 

 quite abundant in the Cambrian seas. 



Dittmar gives the following composition and percentage of the salts in sea- 

 water : — 



Sodium chloride, Na Cl 27-213 gr. per litre. 



Magnesium chloride, Mg CI2 3*807 " 



Magnesium sulphate, Mg SO4 1*658 " 



Calcium sulphate, Ca SO4 1'260 " 



Potassium sulphate, K2 SO4 0*863 " 



Calcium carbonate, Ca CO3 0*123 " 



Magnesium bromide, Mg Br^ 0*076 " 



35*000 ' 



Thoulet gives a somewhat different composition, though the amount of total salts 

 is much the same, 35 0631 gr. per thousand grams of sea-water: — 



Sodium chloride, NaCl 



Potassium chloride, K Cl 



Rubidium chloride, Rb Cl 



Calcium sulphate, Ca SO* 



Magnesium sulphate, Mg SO* 



Magnesium chloride, Mg Clo 



Magnesium bromide, Mg Br2 



Calcium metaphosphate, Ca (PO3): 

 Calcium bicarbonate, Ca 02 0'^.. . . 

 Iron bicarbonate, Fe C2 O3 



From the analyses that have been made of a great many samples of sea-water, it 

 can be stated that there are about 35 grams of salt in a thousand grams of sea-water. 

 This amount is greater in some regions, for instance in the tropical regions and in the 

 gulf stream, where evaporation is more intense. It is much less in other parts, espe- 

 cially near the continental shores where the flow of fresh water from the coast lessens 

 the proportion of salt. For instance, in my determinations, I found as low as 15-13 

 gr. i)er thousand at Prince Station 18, 19-18 i)er thousand at Station 20, 18-35 per 

 thousand at Station 21, 15-63 per thousand at Station 22, etc. This is easily explained 

 by the fact that there is at those points a mixture of fresh water from the coast. 



However, the average amount of salt in the ocean is about 35 gr. per thousand 

 ]iarts by weight. In the percentage of salts given by Dittmar and Thoulet, the acids 

 and bases have been arbitrarily combined. Still it is very probable that in the water 

 the salts are not found as indicated. The elements and acid radicals are found by 

 analysis, but nothing tells us how they exist in solution. The dissolved substances 

 mainly exist as ions, and from the freezing point and boiling point of sea-water, we 

 calculate the ionic dissociation to be about 90 per cent; thus, only one-tenth of the 

 total solids are present in the water as salts. It would be better, therefore, to write 

 the composition of the solids in sea-wat«r. as it is given by Dr. Johan Hjort : — 



Na 10*722 parts per 1000 30*64% 



Mg 1*316 " " " 3*76% 



Ca 0*420 " " " 1'20% 



K 0*382 " " " 1'09% 



Cl 19*324 " " " 55*21% 



SO4 2*696 " " " 7*70% 



CO3 0*074 0*21% 



Br 0*066 " " " 0*19% 



35*000 100*00% 



From the foregoing, one can readily perceive that the salinity of sea-water is not 

 identical everywhere in the ocean ; it varies in different regions and at different depths. 

 38a— 20^ 



