Mr. Thoreau dedicated his genius with such entire love to the fields, hills and waters of his native town, that he made them known and interesting to all reading Americans, and to people over the sea. The river on whose banks he was born and died he knew from its springs to its confluence with the Merrimack. He had made summer and winter observations on it for many years, and at every hour of the day and night. The result of the recent survey of the Water Commissioners appointed by the State of Massachusetts he had reached by his private experiments, several years earlier. Every fact which occurs in the bed, on the banks, or in the air over it; the fishes, and their spawning and nests, their manners, their food; the shad-flies which fill the air on a certain evening once a year, and which are snapped at by the fishes so ravenously that many of these die of repletion; the conical heaps of small stones on the river-shallows, the huge nests of small fishes, one of which will sometimes overfill a cart; the birds which frequent the stream, heron, duck, sheldrake, loon, osprey; the snake, muskrat, otter, woodchuck and fox, on the banks; the turtle, frog, hyla and cricket, which make the banks vocal,—were were all known to him, and, as it were, townsmen and fellow-creatures; so that he felt an absurdity or violence in any narrative of one of these by itself apart, and still more of its dimensions on an inch-rule, or in the exhibition of its skeleton, or the specimen of a squirrel or a bird in brandy. He liked to speak of the manners of the river, as itself a lawful creature, yet with exactness, and always to an observed fact. As he knew the river, so the ponds in this region.