REPORT ON THE COMPOSITION OF OCEAN-WATER. 
203 
alkalinity determinations in the final adjustment of my numbers for the average composi- 
tion of ocean-water salts, as deduced originally from the 7 7 complete analyses ; but 
I must not omit to state that in this final calculation the values for the lime were 
taken, not from those analyses, but from the results of a later series of more exact deter- 
minations made with three mixtures of Challenger waters representative of certain ranges 
of depth; namely, a mixture (I.) for depths from 0 to 50 fathoms; a mixture (II.) for 
depths from 300 to 1000 fathoms ; a mixture (III.) for depths from 1500 fathoms and more. 
As shallow shore waters do not occur in the series of Challenger samples, I also analysed, 
as No. IV., a water which had been collected for me near Port Louis in Arran, Scot- 
land, at a shallow place where there is abundance of marine vegetation. 
The same set of four waters had before served for an elaborate research on the 
relative quantity of bromine in ocean-water salts. 
From the 77 complete analyses, as thus corrected and supplemented, I calculated 
the following numbers for the average composition of ocean-water salts. The numbers 
under Forchhammer are transcribed from his memoir. 
Average Composition of Ocean- Water Salts. 
Per 100 parts of 
Total Salts. 
Per 100 of Halogen calculated 
as Chlorine. 
Dittmar. 
Dittmar. 
Forchhammer. 
Chlorine, ..... 
55-292 ) 
99-848 
Not determined. 
Bromine, ..... 
0-1884 j 
0-3402 
Not determined. 
Sulphuric Acid, S0 3 , 
6-410 
11-576 
11-88 
Carbonic Acid, C0 2 , . 
0152 
0-2742 
Not determined. 
Lime, CaO, ..... 
1-676 
3-026 
2-93 
Magnesia, MgO, .... 
6-209 
11-212 
11-03 
Potash, KnO, .... 
1-332 
2-405 
1-93 
Soda, Na 2 0, ..... 
41-234 
74-462 
Not determined. 
(Basic Oxygen equivalent to the Halogens), . 
(- 12-493) 
Total Salts, 
100-000 
180-584 
181-1 
* Equal conjointly to 55 376 parts of chlorine, which accordingly is the percentage ol “halogen reckoned a: 
chlorine ” in the real total solids. Compare second footnote on page 138. 
