Fish scale the surface, interacting only with the riblet tips, not causing any high-veloctiy flow in the valleys. Since this high velocity flow now only interacts with the riblet-tip, which is a very small surface area, the momentum transfer which causes drag is now much lower than before, thereby effectively reducing drag. Also, this reduces the cross-stream velocity fluctuations, which aids in momentum transfer too. The rough, sandpaper-like texture of shark and ray skin, coupled with its toughness, has led it to be valued as a source of rawhide leather, called shagreen. One of the many historical applications of shark shagreen was
Creatures of Impulse ever made audiences laugh more in so short a time". In an 1882 assessment of the piece for amateur theatre societies, M. E. James noted that "The singing is a great addition. It is altogether an amusing bit of nonsense, and very original". "The Times" review was less positive than most, saying that although the play was good, more was expected of Gilbert: Creatures of Impulse Creatures of Impulse is a stage play by the English dramatist W. S. Gilbert, with music by the composer-conductor Alberto Randegger, which Gilbert adapted from his own short story. Both the play and the