The fortified Rocher du Bock is pictured at the centre of this vividly coloured gouache. The promontory is foreshortened here, and shown from a north-easterly perspective with the towers of the mighty Bock fortress in the middle distance. Turner’s rendering of the formidable military complex of Vauban, chief military engineer to King Louis XIV, evokes its expansiveness, as the promontory is depicted projecting out towards the horizon line. A vaporous blue mist rises from the Alzette valley below, creeping up the sides of the gorge and obscuring the foundations of the fortress so that sheer cliff and citadel appear constructed of the same gigantic stone. The foreground is occupied by abundant vegetation, and framed, to the left, by a striated rust-red cliff.
As with other of Turner’s Luxembourg gouaches, the colouring here is rich and multifarious, comprised of representational and non-representational pigments such as opaque ochre and dilute purple, which achieves striking chromatic contrasts. To define the foreground foliage and rock formations, Turner has drawn over the gouache and watercolour with pen and brown ink in rough hatching and loose scalloped line. For similar drawings see Tate
D20244,
D20246–D20249,
D20264,
D20270,
D20272–D20273,
D20284–D20285,
N05240; Turner Bequest CCXXI K, CCXXI M–CCXXI P, CCXXII E, CCXXII K, CCXXII M–CCXXII N, CCXXII Y–CCXXII Z.