Definition
A device used by oceanographers to obtain subsurface samples of SEA WATER. The bottle is lowered by wire; its valves are open at both ends. It is then closed 'in situ' by allowing a weight (called a MESSENGER) to slide down the wire and strike the reversing mechanism. This causes the bottle to turn upside down, closing the valves and reversing the REVERSING THERMOMETERS which are mounted in a special thermometer case on it. If, as is usually done, a series of bottles is lowered, then the reversal of each bottle releases another MESSENGER to actuate the bottle beneath it.