Up the blade of grass here a tiny white-shelled snail has crawled, feeling in its dull, dim way that evening is approaching. The coils of the little shell are exquisitely turned--the workmanship is perfect; the creature within, there can be no question, is equally perfect in its way and finds a joy in the plants on which it feeds. On the ground below, hidden among the fibres near the roots of the grass, lies another tiny shell; but it is empty, the life that once animated it has fled-- whither? Presently the falling dew will condense upon it, and at the opening one round drop will stand; after awhile to add its mite to the ceaseless flow of the fountain. Could any system of notation ever express the number of these creatures that have existed in the past? If time is measured by the duration of life, reckoned by their short spans eternity upon eternity has gone by. To me the greatest marvel is the countless, the infinite number of the organisms that have existed, each with its senses and feelings, whose bodies now help to build up the solid crust of the earth. These tiny shells have had millions of ancestors: Nature seems never weary of repeating the same model. In the osier-bed the brook-sparrow chatters; there, too, the first pollard willow stands, or rather leans, hollow and aged, across the water. This tree is the outpost of a thousand others that line the banks of the stream for mile after mile yonder down in the valley. How quickly this little fountain grows into a streamlet and then to a considerable brook!--without apparently receiving the waters of any feeders. In the first half-mile it swells sufficiently, if bayed up properly, to drive a mill--as, indeed, many of the springs issuing from these coombes do just below the mouth. In little more than a mile, measuring by its windings, it becomes broad enough to require some effort to leap it, and then deepens into a fair-sized brook.