Mariotte's Bottle

Apparatus employed to obtain a uniform flow of liquid. Through a stopper at top pa es an open vertical tube with the lower end below the surface of the liquid. Near the bottom is a lateral efflux tube. If this be opened the velocity of efflux presently becomes constant, and is due to b to the IMG:content-1252.png:[graphic][merged small] lower western rivers, horizontal engines of long stroke are used, so as to distribute the weight over the hull, which has to be a tru of little depth. In stern-wheelers the two engines are coupled together; in side-wheel ve els the engines are usually sep separate, by which rapid maneuvering power is secured. Such engines usually work non-condensing. non-condensing. A few vertical back-acting engines ngines without walking beam are still running, but no new ones have been built. In the past, for paddle-wheel propulsion, side-lever engines have been used, and oscillating engines (see both titles), to bring down the center of gravity and keep the engine below range of hostile shot.