The river Durance passes through the western part of this department, receiving (left), as affluents, the Ubaye, the Bleone and the Asse (the entire course of each of these rivers is included within the department) as well as the Verdon, the upper course of which is within the department, while the lower course forms its southern limit.
It soon becomes the boundary for a while between the departments of the HautesAlpes 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 Busch, 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.
Ravenel, with a notice by Sainte-Beuve (1846) and by Eugene Asse (1873).
But in the great Sala dell' Asse (or della Torre) abundant traces of Leonardo's own hand were found, in the shape of a decoration of intricate geometrical knot or plait work .combined with natural leafage; the abstract puzzle-pattern, of a kind in which Leonardo took peculiar pleasure, intermingling in cunning play and contrast with a pattern of living boughs and leaves exquisitely drawn in free and vital growth.