During the greater part of the year, the Aygues is a broad expanse of white pebbles; of the torrent naught remains but the bed, a furrow of enormous width, comparable with that of its mighty neighbour, the Rhone. Let the rain fall persistently, let the snows melt on the slopes of the Alps; and the thirsty furrow fills for a few days: roaring, it overflows to a great distance and turbulently shifts its shoals of pebbles. Return a week later. The roar of the flood is succeeded by silence. The terrible waters have disappeared, leaving on the banks, as the trace of their brief passage, wretched muddy puddles soon absorbed by the sun. These sudden freshets bring a thousand live gleanings swept off the flanks of the mountains. The dry bed of the Aygues is a most interesting botanical garden. There you may gather many vegetable species brought down from the higher levels, some temporary, disappearing without offspring in a single season, others persisting and adapting themselves to the new climate. They come from far away, from the heights, these exiles; to pluck this one or that in its true environment you would have to climb Mont Ventoux, pass beyond the zone of the beeches and reach the altitude where trees cannot grow. Alien zoology in its turn is represented in the osier-beds, whose calm is disturbed only during unusually prolonged floods. My attention is attracted especially by the land-mollusc, that champion stay-at-home. In stormy weather, when the thunder growls—lou tambour di cacalauso, as the Provençal calls it—the most that the Snail permits himself in the matter of moving about is to issue from his stronghold, some crevice in the rocks, and to browse before his door upon the grasses, mosses and lichens made tender by the flood. It takes a cataclysm to make that one travel! The wild freshets of the Aygues succeed in doing so. They bring into my part of the world and deposit in the osier-thickets the largest of our Snails, Helix pomatia, the glory of Burgundy. [45] Rolled down the grassy mountain-slopes by the showers, the exile defies immersion within the water-tight cover of his chalky operculum; he endures the jolting, thanks to his strong shell. He travels by stages, from one osier-bed to another. He descends as far even as the Rhone and colonizes the Île des Rats and the Île du Colombier opposite the mouth of the Aygues. Whence does he come, this enforced emigrant, whom one would vainly seek elsewhere in the land of the olive? He loves a moderate temperature, green turf, cool shades. His place of origin is certainly not here, but far away on the rounded heights of the lower, outermost Alps. The highlander’s exile none the less seems pleasant. The big Snail does quite well in the marshy scrub on the banks of the torrent.