The tide was well out when I started to follow, or rather taste the fresh water over the sands. The Brewster flats, as they are called, were alive with light and constantly changing where they stretched out on the earth’s curve. Minor investigation took place in maximum horizons. I walked toward the weir, or fish trap, one of three in the distance, long-poled stockades a quarter of a mile or so apart, hung with nets like veils or the peaked coifs of nuns. A silver sun was beginning to lift through sheets of low fog, and a cool wind blew across the sands. It made my ears boom with that hollow sound of deep marine that you hear in a shell. I saw a small flock of brant standing off, their heads alert for danger, ready to thrust up and go when I came. I approached lines of brown dunlins, red-backed sandpipers, sanderlings, black-bellied plovers, which stood and scurried, peeped and cried, flew forward into the wind for short stretches, and came down again. As the sun rose farther up, clouds began to be reflected in the lanes between the ribbed sands, and there were thousands of gulls standing in a silver, immeasurable distance, while those sharp, light arrows, the terns, flew overhead. The flats with their brown deserts, their lakes, and pools, and veins, were like the patterned floors, the reaches of the great civilizations of man. The dawn fogs blew off. I was waking up to an architecture of space. Now from these tidal areas the plains of the sea rove out indefinitely. You can get a look at the universal map without benefit of signposts, and the coming on of fish represents great standards of inevitability. “But look,” a scientist might say, “in this unlimited space of yours, the mating animal only has a tiny area to travel in; a few miles at sea, if in the case of the alewives, they do stay offshore, and perhaps two or three miles inland. They are limited in space, and limited in numbers accordingly.” True, but we might add that it is this limitation, in alewives at least, that makes increase possible. They are one of the most easily managed of all marine species. Clear out the obstructions in their way; restock a lake and river system, or pond and stream, and the fish return, the population rises. Alewife management depends on their almost relentless drive to go back where they came from. No life insists on its locality more strongly. Home in their case is a definite route, a round way, small if you like, but spinning in larger circles, where birth leads back to its necessity.