Because it is full of invisible chalk. In every gallon of that water there are, perhaps, fifteen grains of solid chalk, which was once inside the heart of the hills above. Day and night, year after year, the chalk goes down to the sea; and if there were such creatures as water-fairies--if it were true, as the old Greeks and Romans thought, that rivers were living things, with a Nymph who dwelt in each of them, and was its goddess or its queen--then, if your ears were opened to hear her, the Nymph of Itchen might say to you-- So child, you think that I do nothing but, as your sister says when she sings Mr. Tennyson's beautiful song, "I chatter over stony ways, In little sharps and trebles, I bubble into eddying bays, I babble on the pebbles." Yes. I do that: and I love, as the Nymphs loved of old, men who have eyes to see my beauty, and ears to discern my song, and to fit their own song to it, and tell how "'I wind about, and in and out, With here a blossom sailing, And here and there a lusty trout, And here and there a grayling, "'And here and there a foamy flake Upon me, as I travel With many a silvery waterbreak Above the golden gravel, "'And draw them all along, and flow To join the brimming river, For men may come and men may go, But I go on for ever.'" Yes. That is all true: but if that were all, I should not be let to flow on for ever, in a world where Lady Why rules, and Madam How obeys. I only exist (like everything else, from the sun in heaven to the gnat which dances in his beam) on condition of working, whether we wish it or not, whether we know it or not. I am not an idle stream, only fit to chatter to those who bathe or fish in my waters, or even to give poets beautiful fancies about me. You little guess the work I do. For I am one of the daughters of Madam How, and, like her, work night and day, we know not why, though Lady Why must know. So day by day, and night by night, while you are sleeping (for I never sleep), I carry, delicate and soft as I am, a burden which giants could not bear: and yet I am never tired. Every drop of rain which the south-west wind brings from the West Indian seas gives me fresh life and strength to bear my burden; and it has need to do so; for every drop of rain lays a fresh burden on me. Every root and weed which grows in every field; every dead leaf which falls in the highwoods of many a parish, from the Grange and Woodmancote round to Farleigh and Preston, and so to Brighton and the Alresford downs;--ay, every atom of manure which the farmers put on the land--foul enough then, but pure enough before it touches me--each of these, giving off a tiny atom of what men call carbonic acid, melts a tiny grain of chalk, and helps to send it down through the solid hill by one of the million pores and veins which at once feed and burden my springs. Ages on ages I have worked on thus, carrying the chalk into the sea. And ages