REPORT ON THE COMPOSITION OP OCEAN-WATER. 
15 
say that-, in all cases, the solution analysed included 3 - 25 grms. of pure Na 2 S0 4 and 0 - 639 
grm. of pure MgS0 4 , i.e., the quantities of these salts contained in the sulphates from about 
100 c.c. of sea-water. For experiments 1 to 5 the ordinary “ pure ” preparations were used, 
as kept in stock for analytical work generally ; for the rest of the experiments the 
sulphates were specially prepared, so as to ensure the absence from them of every trace 
of potash ; the soda salt from recrystallised bicarbonate and pure sulphuric acid ; the 
magnesia salt as follows : — The double salt Mg(NH 4 ) 2 (C0 3 ) 2 + 4H 2 0 was prepared from 
“ pure ” sulphate of magnesia by precipitation with a large excess of neutral carbonate of 
ammonia, the precipitate washed thoroughly with the reagent, until sure to be free from 
mother-liquor, and then ignited so as to reduce it to magnesia. Weighed quantities of this 
No. 
The Precipitant contained 10 per cent, 
of Metal, as — 
Obtained Mgrms. of 
Used Mgrms. of 
K„0. 
PtCl 4 
or PtCl 6 H 2 . 
PtCl 6 Na 2 . 
PtCl 6 Li 2 . 
Pt 
k 2 o. 
1 
... 
2 c.c. 
3-8 
1-8 
o-o 
2 
2 c.c. 
2-45 
1-16 
0 
3 
2 c.c. 
99D5 
47-01 
45-37 
4 
2 c.c. 
96-55 
45-81 
46-08 
5 
Lo 
st. 
6 
2 c.c. 
3-6 
1-71 
o-o 
7 
2 c.c. 
3-2 
1-49 
o-o 
8 
IT c.c. 
Lc 
st. 
9 
IT c.c. 
96-1 
45-5 
46-3 
10 
1-5 c.c. 
96-8 
45-93 
46-77 
11 
T5 c.c. 
97-1 
46-08 
46-77 
12 
2D c.c. 
96-4 
44-75 
45-7 
13 
2D c.c. 
94-3 
45-75 
46-57 
14 
3‘0 c.c. 
96-1 
45-6 
46-2 
15 
3D c.c. 
97-6 
46-33 
46-56 
16 
... 
2 c.c. 
3-3 
1-56 
o-o 
17 
... 
2 c.c. 
4-5 
2-13 
o-o 
18 
2 c.c. 
99-1 
46-94 
46-16 
