REPORT ON THE COMPOSITION OF OCEAN- WATER. 
227 
No. of Water. 
C.c. p 
N, 
er litre. 
o 2 
0 2 calculated. 
8 
1661 
13-74 
1-65 
7-15 
300 
There was no lack of anomalous results, but I did not succeed in tracing these to 
natural causes. I suspect that some of the anomalies must be referred back to the 
difficulty of exhaustively extracting the gases from a sample of water by Jacobsen’s method. 
Sometimes, also, the bottle used on board the Challenger for collecting the deep-sea waters 
may not have worked correctly, and may have brought up water from a depth different 
from that intended. Now and again, also, in the working of the Jacobsen process, 
atmospheric air may have leaked into the tube intended to receive the water gases only. 
Even on shore it is not always possible to prevent the occurrence of such accidents, and 
on board ship they are still more likely to occur. 
There was no need for a special investigation to prove that in the ocean the equilibrium, 
in regard to the absorbed nitrogen and oxygen, is maintained by the atmosphere ; and it 
stands to reason, likewise, that the ocean constantly adds to the atmospheric oxygen in 
the tropics, while it takes away from it in the colder latitudes. But as even the corre- 
sponding influence on the atmospheric carbonic acid has so far defied the powers of 
chemical analysis, the fluctuations of the percentage of oxygen in the air, which are caused 
by the sea, must be immeasurably small. 
Suggestions for Future Work. 
In conclusion, I may be permitted to offer a few suggestions in regard to the manner 
in which these researches on the composition of ocean-water should be continued. 
That they ought to be continued, and extended, and that it is the special vocation of 
this country to take the matter in hand, will be admitted. 
The work involved may be arranged under two heads, one of which would comprise 
the various kinds of observations and experiments which might easily be carried on by any 
intelligent seafaring man, even if he were devoid of all professional knowledge of chemistry. 
I here refer chiefly to, — (1) Salinity determinations by means of the hydrometer and a 
good thermometer. A set of handy and relatively small hydrometers, graduated so as to 
give the specific gravity for say 60° F. quite directly and without the aid of attached 
weights, would easily be supplied by a good mechanician for a few pounds sterling ; and 
any intelligent man would soon learn to use these. Each of Her Majesty’s ships should 
be provided with such a set, and a number of good thermometers, both verified by a 
scientific chemist or physicist. (2) Observations on the behaviour of sea-water on 
