DURANCE (anc. Druentia)  , one. of the principal rivers descending from the French slope of the Alps towards the Mediterranean . Its total length from its source to its junction with the Rhone (of which it is one of the principal affluents), a little below Avignon, is 217i M . For the greater part of its course it flows in a south-westerly direction, but near Pertuis gradually bends N.W. and thenceforth preserves this direction . It passes through the departments of Hautes-Alpes, of Basses-Alpes, and between those of Vaucluse and Bouches-du-Rhone . It is commonly said to take its origin in some small lakes a little south of the summit plateau of the Mont Genevre Pass . But really this stream is surpassed both in volume and length of course by two others which it joins beneath Briancon:—the Clairee, flowing in from the north, through the smiling Nevache glen, at the head of which, not far from the foot of the Mont Thabor (10,440 ft.), it rises in some small lakes, on the east side of the Col des Rochilles; and the Guisane (flowing in from the north-west and rising near the Col du Lautaret, 68o8 ft.) . The united stream soon receives its first affluent, the Cerveyrette (left), and, after having passed through some fine deep-cut gorges, the Gyronde (right) . It then runs through a stony plain, where it frequently overflows and causes great damage, this being indeed the main characteristic of the Durance throughout its course . At the foot of the fortress of Mont Dauphin it receives (left) the Guil, which flows through the Queyras valley from near the foot of Monte Viso . Some way beyond it passes beneath Embrun, the first important town on its banks . It soon becomes the b9undary for a while between the departments of the Hautes-Alpes and of the Basses-Alpes, and receives successively the considerable Ubaye river, flowing from near the foot of Monte Viso past Barcelonnette (left), and then the small stream of the Luye (right), on which, a few miles above, is Gap . It enters the Basses-Alpes shortly before reaching Sisteron, where it is joined (right) by the wild torrent of the Buech, flowing from the desolate region of the Devoluy, and receives the Bleone (left) (on which Digne, the capital of the department, is situated) and the Asse (left), before quitting the department of the Basses-Alpes just as it is reinforced (left) by the Verdon, flowing from the lower summits of the Maritime Alps past Castellane .

After passing through some narrow gorges near Sisteron the

bed of the river becomes wide, and spreads desolation around, the frequent overflows being kept within bounds by numerous dykes and enbankments . These features are especially marked when the river, after leaving the Basses-Alpes, soon bends N.W. and, always serving as the boundary between the departments of Vaucluse (N.) and of the Bouches-du-Rhone (S.), passes Cavaillon before it effects its junction with the Rhone . The drainage area of the Durance is about 5166 sq. m., while the height it descends is 6550 ft., if reckoned from the lakes on the Mont Genevre, or 7850 ft. if we take those at the head of the Nevache valley as the true source of the river . (W . A . B .