In consequence of this composite formation, amethyst is apt to break with a rippled fracture, or to show "thumb markings," and the intersection of two sets of curved ripples may produce on the fractured surface a pattern something like that of "engine turning."
With v=o, the angular velocity of the cylinder is 2w; in this way the velocity may be calculated of the propagation of ripples and waves on the surface of a vertical whirlpool in a sink.
The rocky sides are finely marked with waves and ripples, as if running water had suddenly been petrified.
In front of this is a double series of stationary waves, the gravitation waves forming a series increasing in wave-length with their distance in front of the body, and the surface-tension waves or ripples diminishing in wave-length with their distance from the body, and both sets of waves rapidly diminishing in amplitude with their distance from the body.
In observations upon ripples the factor involving h may usually be omitted, and thus in the case of water (p= I) ?3 g ?2 T = 2 2 4, r (3) simply.
For the first week, whenever I looked out on the pond it impressed me like a tarn high up on the side of a mountain, its bottom far above the surface of other lakes, and, as the sun arose, I saw it throwing off its nightly clothing of mist, and here and there, by degrees, its soft ripples or its smooth reflecting surface was revealed, while the mists, like ghosts, were stealthily withdrawing in every direction into the woods, as at the breaking up of some nocturnal conventicle.