The doublings, or _horse-shoes_, of this Wye, or _Vaga_ as the Romans named it, within its circle of rocks, so exquisitely fringed with green and purple lichens (like the Danube, round the castle of Hayenbach in the gloomy gorge of Schlagen, or the Crook of Lune, in Westmoreland, and many others), illustrate at once the nature of the stratification on the earth’s surface; even the varied tints of these mountain streams may read the student a practic lesson in geology. From the lime-rock springs the azure-blue, as the Glaslyn stream, at Beddgelert, the Rhone, and the Traun in Styria; from the chalk ripples the grey water of the Dee and the Arve; from the clay hills the stream comes down yellow, as “the Derwent’s amber wave;” and where the peat-mosses abound, especially in the autumnal flood, the stream is of a rich and dark sienna brown, as the Conway, and the Mawddach, in Merioneth; or even of transparent black, as the Elain, which flows down through the white schist rocks of Cardiganshire. CAST. And is there wisdom, Evelyn, in thus “Flying from Nature to study her laws, And dulling delight by exploring the cause?” I do fear that this analytic study of nature destroys the romance of life which flings around us its rainbow beauty. Oh, for those halcyon days of infancy, when every thought was a promise; when hope, the _dream_ of waking men, was lost in its fulfilment; and even fear itself was a thrill of romance! Behold yon silver moon! it is, to the _poet’s eye_, an orb of unsullied beauty, and the planets and their satellites glitter like diamond studs in the firmament. Yet shift but the lens of the star-gazer, and lo! dark and murky spots instantly shadow o’er its purity; nay, have I not read that one deep astronomer, Fraüenhofer, has discovered mountains and cities; and another, Sir John Herschell, the laying down of rail-roads in the moon? So the optics of Gulliver magnified the court beauties of Brobdignag into monsters, and the auburn tresses of a maid of honour into a coil of dusty ropes! EV. A truce, fair Castaly. If science discovers defects, does it not unfold new beauties, a new world of animated atoms, endowed with faculties and passions as influential as our own? Nay, science has thrown even a _poetry_ around the blue mould of a cheese-crust; and in the bloom of the peach the microscope has shown forth a treasury of flowers, and gigantic forests, in the depths of which the roving animalcule finds as secure an ambush as the lion and the tiger within the gloomy jungles of Hindostan. In a drop of liquid crystal the water-wolf chases his wounded victim, till it is changed to crimson with its blood. Ehrenberg has seen monads in fluid the 24,000th part of an inch in size; and in one drop of water 500,000,000 creatures—the population of the globe! I hope, Castaly, you will not, like the Brahmin, break your microscope, because it unfolds to you these wonders of the water.