At the head and centre of the vast amphitheatre, and at the foot of one of its enormous rocks, there is a cavern of proportional size, hollowed out by the hand of nature.

Its opening is an arch sixty feet high; but it is a double cavern, there being an interior one with an entrance thirty feet high.

In the midst of these there is an oval basin, having eighteen fathoms for its longest diameter, and from this basin rises the copious stream which forms the Sorgue.

The surface of the fountain is black, an appearance produced by its depth, from the darkness of the rocks, and the obscurity of the cavern; for, on being brought to light, nothing can be clearer than its water.

Though beautiful to the eye, it is harsh to the taste, but is excellent for tanning and dyeing; and it is said to promote the growth of a plant which fattens oxen and is good for hens during incubation.
Strabo and Pliny the naturalist both speak of its possessing this property.
The river Sorgue, which issues from this cavern, divides in its progress into various branches; it waters many parts of Provence, receives several tributary streams, and, after reuniting its branches, falls into the Rhone near Avignon.
Resolving to fix his residence here, Petrarch bought a little cottage and an adjoining field, and repaired to Vaucluse with no other companions than his books.