A container used for sampling sea water and consisting of a brass cylinder fitted with a plug valve at each end and capable of being reversed in position. The two valves close simultaneously. The cylinder holds about 1200 cc. In use, the bottle is lowered on a wire with the valves open. A weight sliding down the wire is let go from the surface when the bottle has reached depth. The weight, called a messenger, closes the valves and reverses the bottle. There are usually several bottles, fastened at different depths along the wire, so the messenger closes each bottle in succession. The Nansen bottle (also called the Nansen water bottle) is the one most widely used in oceanography. The Ekman bottle has plates seated in rubber gaskets as valves.