"Sand-strewn caverns, cool and deep,
Where the winds are all asleep;
Where the spent lights quiver and gleam,
Where the salt weed sways in the stream."
These delicately "chambered" shells were once the homes of creatures which lived in the sunless depths of the ocean, for though it is totally dark at the bottom of the deep, deep sea, life is now known to exist at all depths below the surface of the ocean; on the ocean-floor starfishes and their relations abound, and some of those brought from a great depth are very beautiful indeed—telling to those who have eyes to see, the same tale as the little fern buried in the coal—that it is the glory of every created thing to show forth something of its Creator, even in hidden places where no human eye can trace its loveliness.
I am sure when we speak of the treasures of the sea, you are thinking of places where pearls lie deep, hidden in the shell of the oyster—but I did not know until lately that not only iron and copper, but also gold and silver, are found in sea water.
And now what can we say of the colour of the sea? I used to think that it was always a clear green, but that was because the sea which I knew appeared to be that colour, for I had seen it only near the shore, where the bottom was fine white sand, and the sunset light made the water shine like an emerald. And so the sea was green to me, and I was often puzzled and vexed to find that I could never catch this beautiful green water; for you know that if you dip your bucket where the sea looks greenest or bluest, all the lovely colour will seem to be left behind, and your bucket-full will look as colourless as water drawn from a well. Where the sea is dark blue, you may be sure that it is deep where it looks gold and purple, the sun has tinged it with the glory of his rising and setting; where it is grey and sad, it takes its sorrowful hue from the rain-clouds overhead. These are some of the reasons why the sea is of such different colours, but the water is sometimes coloured, to some extent, by myriads of living things which give it a reddish tinge; in the cold Northern Ocean, where the icebergs are, travellers tell us the sea is green because there its tiny inhabitants are green; while those who have sailed in the South American waters tell of countless swarms of minute creatures which make them glow like fire on a dark night, lighting up the crest of every wave as it rolls past the ship.
The sea is also coloured by those beautiful plants which we often call by one common name—seaweeds, but which are almost as varied in their way as the land plants are.
Columbus, when sailing sadly through unknown seas in search of the New World of which he had dreamed so long, came upon water so covered with long green weeds that it seemed like a floating meadow, while his vessels could hardly make their way through the grassy tangles of what is now known as the Gulf-weed.
I have seen the sea off the coast of Ireland green for miles, with long, ribbon-like plants covering its sandy bottom, sheltering, and perhaps helping to feed, the millions of crawling and running and swimming creatures, many of them so small as to be nearly invisible, which find their home there. This sea-grass, or Zostera, the only flowering plant to be found in the sea, is very useful to the poor people who live near the coast. They gather it when the tide is low, and dry it in the sun, and it serves them for nice soft beds; though I should think they must always keep a briny, fishy smell about them.
[Illustration: "O'ER BANKS OF BRIGHT SEAWEED, THE EBB-TIDE LEAVES DRY.">[
The Irish fisher-folk also gather the common brown seaweed with pods, which are really air-bladders, and serve to keep it afloat. I have many a time watched the women and children wading among the pools, cutting it from the rocks with sickles, and putting it into baskets, which they carry home on their backs; for this precious harvest of the sea is what they depend upon to make their potatoes grow well and yield a plentiful crop. There is another kind of seaweed, of a pretty purple colour, which they eat, and call it by an Irish name which means "leaf of the water."
But it is far away in the watery valleys of the great Pacific, where the sea is very calm, that the ocean forests grow. I have read that there giant leaves of the sea grow upon stems longer than those of our tallest trees, and spread abroad like waving palms. Though you are not likely ever to see such seaweeds as these, you will find, wherever you may be, though much more abundantly on some shores than others, some of those beautiful "weeds"—green, red, or brown—which have their use as well as their beauty; for they help to purify the water, just as plants do the air. Perhaps I should not promise more than the brown Tangle and the green Ulva, with its bright lettuce-like leaves; for red seaweeds belong to deep water, and are not easy to find. Many an hour have I spent peering and groping in the little pools at low water in search of these same much-prized rosy-tinted "flowers of the sea"; and many a disappointment I have had, even after a fortunate find, in seeing how soon the lovely colour faded, in spite of all my efforts to keep it.