REPORT ON THE COMPOSITION OF OCEAN-WATER. 
243 
Hence we see that although fused chloride of silver may absorb chlorine, such 
chlorine is readily and exhaustively expelled by a short exposure of the fused product to 
dry air. This point being settled, the second question was — Does pure bromide of silver, 
when chlorinated and otherwise manipulated as the mixed haloid precipitates in the sea- 
water analyses were, yield the exact proportion of chloride demanded by the atomic 
weights'? In the first experiment 3'4538 grams of dry pure bromide of silver were 
operated upon, with the following results : — 
Weight of bromide after renewed drying in dry air at 150° C., . . 3 '4543 grams. 
After fusion in dry air, ....... 3'4541 „ 
The boat cracked, but nothing ran out of it hence the experiment was continued. 
Haloid after treatment with chlorine, — 2 - 6354 grams. Hence, calculating from the 
fused bromide of silver, loss in chlorination is CC8187 grams, corresponding, by calculation, 
to 1‘4712 grams of bromine. The original bromide, by calculation, contained 1/4699 ; 
error in analysis = -h 1*35 mgrms. of bromine, corresponding to 3'27 mgrms. of bromide 
of silver. 
Two other similar experiments were made ; the following is a summary of 
the results : — 
Experiment 
I. 
II. 
III. 
Fused bromide of silver taken, 
3-4541 
2-4659 
2 - 5814 grams. 
Containing bromine by theory, . 
1-4699 
1-0493 
1-0985 „ 
Loss on chlorination, .... 
0-8187 
0-5838 
0-6115 „ 
Corresponding to bromine, 
1-4712 
1-0491 
1-0989 „ 
Error in bromine found, 
+ 1-35 
-0-24 
+ 0'39 mgrms. 
Mean absolute error, .... 
+ 0'66 milligrams. 
This was very satisfactory, but it remained to be seen what degree of exactitude 
could be obtained in the chlorination of a mixture of much chloride and little bromide 
of silver, similar to those which presented themselves in the sea-water analyses. 
In these analyses, as stated in the memoir, the bromine had been eliminated from 
1 kilo of sea-water, in each case, as far as possible, by two successive precipitations each time 
* The boat, as the reader remembers, always remained within its piece of Bohemian tubing, which would collect 
the result of any leakage. 
