REPORT ON THE COMPOSITION OF OCEAN- WATER. 
245 
water thus supplemented was then analysed for bromine in exact accordance with 
the method described on page 98 as having served for the Challenger water mixtures. 
The following is a summary of the results : — 
Experiment. 
Bromine due. 
Mgrms. 
Bromine found. 
Error. 
I. Precip. 
II. Precip. 
Total 
i. 
66-09 
61-31 
5-22 
66-53 
+ 0-44 
ii. 
66-26 
61-57 
5-04 
66-61 
+ 0-35 
hi. 
6610 
61-15 
4-32 
65-47 
-0-63 
IV. 
66-21 
62-37 
4T4 
66-51 
+ 0-30 
The error in three out of the four cases was positive, and amounted to about 0'4-r- 66 or 
0*00606 of the quantity to be determined. If we apply the corresponding correction to the 
value 0*3402 which we found for the bromine present in our Challenger waters, for every 
100 of chlorine we arrive at the number 0'3381 ; but I think we had better allow the 
original number 0*3402 to stand as it is. Strictly speaking, we ought to subtract from 
each of the quantities of bromine found the 0*36 mgrms. of pwasAbromine which the 
biank analysis of the original water had brought out (see page 238). If we did so, the 
errors would be reduced in — 
Experiment I. II. III. IV. 
To +0-08 -0*01 -0-99 - R06 
In any case the number 0*3402, which I adopted as representing the weight of 
bromine present in 100 of halogen reckoned as chlorine, may, I think, be adopted as 
coming very near the truth. 
Effect of Freezing on the Distribution of the Bromine in Sea-Water Salts. 
At an early stage of the Bromine Investigation I made an elaborate series of 
experiments for ascertaining whether a sea-water which has lost water by partial freezing 
contains more or less bromine per 100 of chlorine than it did before. Unfortunately the 
bromine determinations involved were made according to the faulty method referred 
