the Hawaiian Islands. . . . On the bottom of the ocean there is a constant rain of sediment, formed by the death of animals which have taken carbonate of lime from the waters, and built it into shells and skeletons, which, when they die, falls to the sea bottom. The sea-bed is made of an ooze chiefly composed of remnants of these shells. . . . The cause of waves is friction of the wind. Waves rarely rise more than twenty or thirty feet; waves sixty feet high have been noted, counting from the lowest point of the trough to the highest point of the crest, but this is very unusual. A wave of large dimensions affects the sea to a depth of two or three hundred feet, and may last for a long time after its cause has disappeared; travelers in ships often run into a rough sea when the sun is shining brightly, and there is no wind. These big waves also cause destruction on the beaches, and the shore line is always being worn away. . . . In most parts of the earth, the tide rises twice each day; every twelve hours and twenty-five minutes there is a high tide, with a low tide between. At Key West the tide rises only two or three feet; in some other places the tide rises sixty feet, and comes in as fast as a man can run. It is believed that in some way the tide is caused by the moon. . . . The sea is more interesting than the surface of the earth, but its story is scarcely intelligible to those who have not been trained in the alphabet of zoölogical technicalities. I read a book today about the sea, and have a headache from trying to understand it. All our rain comes from the ocean; it is said that the evaporation of the Red Sea amounts to eight feet per year, owing to the great heat of the countries surrounding it. One
