H

1. Halosphaera, 301, 302

2. Heat:

   1. conducted through ocean bottom, 110

   2. exchange, ocean-atmosphere, 114, 115

      1. off Norwegian coast, 656

   3. specific, 61, 62

   4. transformed from kinetic energy, 110

   5. transported by ocean currents, 99

3. Helium, 189

4. Herring, numbers correlated with copepods, 892, 906, 907

5. Histogram, 970, 980

6. Holoplankton:

   1. characteristic types of, 816, 817

   2. dispersal of, 862–863

   3. numbers of species of, 868

7. Hydrogen-ion (seepH):

   1. related to organisms, 268, 770

8. Hydrogen sulphide, 187

   1. amounts in sea water, 189

   2. at bottom of basins, 1028

   3. exclusion of animals by, 871, 872

   4. importance to precipitation of iron, 952, 1032

   5. in Black Sea, 651, 917

   6. in sediments, 995

9. Hydrometers, 53

10. Hypoplankton, 814

11. Hypsographic curve, 19