Who wrote
"the market is like a lake agitated by the wind, where the water is
incessantly seeking its level without ever reaching it. But whereas there are
days when the surface of a lake is almost smooth, there never is a day when
the effective demand for products and services equals their effective supply
.... For, just as a lake is, at times, stirred to its very depths by a storm,
so also the market is sometimes thrown into violent confusion by *crises*,
which are sudden and general disturbances of equilibrium"?