So they passed by in their joy, like a dream, on the murmuring ripple."Such a rhapsody may be somewhat out of order, even in a popular scientific book; and yet one cannot help at moments envying the old Greek imagination, which could inform the soulless sea-world with a human life and beauty. For, after all, star-fishes and sea-anemones are dull substitutes for Sirens and Tritons; the lamps of the sea-nymphs, those glorious phosphorescent medusae whose beauty Mr. Gosse sets forth so well with pen and pencil, are not as attractive as the sea-nymphs themselves would be; and who would not, like Menelaus, take the grey old man of the sea himself asleep upon the rocks, rather than one of his seal-herd, probably too with the same result as the world-famous combat in the Antiquary, between Hector and Phoca? And yet - is there no human interest in these pursuits, more humanity and more divine, than there would be even in those Triton and Nereid dreams, if realized to sight and sense? Heaven forbid that those should say so, whose wanderings among rock and pool have been mixed up with holiest passages of friendship and of love, and the intercommunion of equal minds and sympathetic hearts, and the laugh of children drinking in health from every breeze and instruction at every step, running ever and anon with proud delight to add their little treasure to their parents' stock, and of happy friendly evenings spent over the microscope and the vase, in examining, arranging, preserving, noting down in the diary the wonders and the labours of the happy, busy day. No; such short glimpses of the water-world as our present appliances afford us are full enough of pleasure; and we will not envy Glaucus: we will not even be over-anxious for the success of his only modern imitator, the French naturalist who is reported to have fitted himself with a waterproof dress and breathing apparatus, in order to walk the bottom of the Mediterranean, and see for himself how the world goes on at the fifty-fathom line: we will be content with the wonders of the shore and of the sea-floor, as far as the dredge will discover them to us. We shall even thus find enough to occupy (if we choose) our lifetime. For we must recollect that this hasty sketch has hardly touched on that vegetable water-world, which is as wonderful and as various as the animal one. A hint or two of the beauty of the sea-weeds has been given; but space has allowed no more. Yet we might have spent our time with almost as much interest and profit, had we neglected utterly the animals which we have found, and devoted our attention exclusively to the flora of the rocks. Sea-weeds are no mere playthings for children; and to buy at a shop some thirty pretty kinds, pasted on paper, with long names (probably mis-spelt)written under each, is not by any means to possess a collection of them. Putting aside the number and the obscurity of their species, the questions which arise in studying their growth, reproduction, and organic chemistry are of the very deepest and most important in the whole range of science; and it will need but a little study of such a book as Harvey's "Algae," to show the wise man that he who has comprehended (which no man yet does) the mystery of a single spore or tissue-cell, has reached depths in the great "Science of Life" at which an Owen would still confess himself "blind by excess of light." "Knowest thou how the bones grow in the womb?" asks the Jewish sage, sadly, half self-reprovingly, as he discovers that man is not the measure of all things, and that in much learning may be vanity and vexation of spirit, and in much study a weariness of the flesh; and all our deeper physical science only brings the same question more awfully near. "Vilior alg?" more worthless than the very sea-weed, says the old Roman: and yet no torn scrap of that very sea-weed, which to-morrow may manure the nearest garden, but says to us, "Proud man! talking of spores and vesicles, if thou darest for a moment to fancy that to have seen spores and vesicles is to have seen me, or to know what I am, answer this. Knowest thou how the bones do grow in the womb? Knowest thou even how one of these tiny black dots, which thou callest spores, grow on my fronds?" And to that question what answer shall we make? We see tissues divide, cells develop, processes go on - but How and Why?

These are but phenomena; but what are phenomena save effects?

Causes, it may be, of other effects; but still effects of other causes. And why does the cause cause that effect? Why should it not cause something else? Why should it cause anything at all?

Because it obeys a law. But why does it obey the law? and how does it obey the law? And, after all, what is a law? A mere custom of Nature. We see the same phenomenon happen a great many times; and we infer from thence that it has a custom of happening; and therefore we call it a law: but we have not seen the law; all we have seen is the phenomenon which we suppose to indicate the law.