USE OF OCEANOGRAPHY—DEACON 365 
sure a more regular supply, and thus a more economical operation of 
freezing and canning plants. 
RAW MATERIALS FROM THE SEA 
China still takes at least 2 million tons of common salt from the sea 
every year, and India extracts some one and a half million tons; the 
world total is about 5 million tons per year. This, of course, is an 
infinitesimal fraction of the total amount of salt in the ocean. The 
world production of magnesium from the sea probably amounts to 
about 300,000 tons per annum, and that of bromine 100,000 tons. 
Many other chemical products are present in the sea, but they are so 
greatly diluted that no profitable methods for extracing them have 
yet been found. Potassium, for example, has been obtained from the 
ocean, but it is much more profitable to extract it from inland seas 
which are partly or completely dried up, such as the very saline 
Dead Sea or the marine deposits of Stassfurt (Germany), Alsace, and 
New Mexico. 
The Chilean nitrate deposits, not to be confused with those of guano, 
are also believed to be of marine origin. Some iodine is still produced 
from seaweed, but most of the world’s supply comes from the Chilean 
nitrate beds and from concentrated natural brines. The ultimate 
origin of petroleum seems to be the decomposition of organic material 
at the bottom of former, very fertile, ocean basins; if this is true, the 
immensity of petroleum reserves gives some idea of the scale on which 
the ocean can produce organic material. 
The present problems encountered in extracting chemicals from the 
sea are the problems of chemical engineering concerned with the 
handling and the concentrating of large volumes of water; but a better 
understanding of geochemical processes, particularly of sedimentation 
and of the conditions under which mineral oils were formed, is likely 
to be a useful guide to the finding of further deposits. 
POWER FROM THE SEA 
Schemes to obtain power from the sea encounter the same kind of 
difficulty as processes for extracting chemicals: tides, waves, and 
currents contain large amounts of energy, but this energy is spread 
over such large areas or volumes of water that the installations needed 
to extract it would not be economical. Small tide mills have operated 
since early times, but large-scale projects have come to nothing; the 
British scheme for the Severn barrage never materialized, and the 
Passamaquoddy scheme in the Bay of Fundy (Canada), started in 
1935, was soon abandoned. 
Technical developments in the design of turbines have opened up 
new possibilities, and a large project (360,000 kw.) intended to pro- 
