Page 409 equipment and instruments 474 



474. Water Specimen Cups 



Water specimen cups are designed to trap samples of sea water at desired depths 

 so they may be brought to the surface for examination. Various types of cups have 

 been designed for this purpose, among which tnay be mentioned the Ekman and Nansen 

 reversing water bottle; the Meteor, Allen, and Nansen-Knudsen closing bottle; the 

 Nansen-Pettersson insulated bottle (see 4716); the Sigsbee watercup; and the Green- 

 Bigelow closing bottle. Only the last two of the types listed are used by the Coast 

 and Geodetic Survey at the present time. 



4741. Sigsbee Watercup 



The Sigsbee watercup (A in figs.. 86 and 87) is an efficient instrument for col- 

 lecting water samples. It is similar to the Tanner-Sigsbee reversing thermometer frame 

 (see 4721) in the way it is attached to the sounding line and in that a propeller is em- 

 ployed to hold the valves closed. There are two poppet valves on the Sigsbee water- 

 cup, one at the top and one at the bottom, which are connected by a rod through the 

 axis of the cylinder so that the two valves open and close simultaneously. The pro- 

 peller is mounted in a frame at the top of the cylinder and revolves freely on the descent, 

 but on the ascent a clutch engages a locking screw pin so that the revolutions force it 

 down against the upper valve. The valves remain open while the instrument descends, 

 they close when it is motionless, but on the ascent they seat firmly and the action 

 of the propeller locks them in this position. When the watercup is hoisted to the rail 

 of the ship, the locking device is first unscrewed, then the upper valve is raised with 

 the fingers, allowing the water to flow from the watercup into a hydrometer jar held 

 under the lower valve. Like the Tanner-Sigsbee reversing frame, the Sigsbee water- 

 cup is designed to clamp on leadline or similar light line and must be placed so that 

 the propeller is at the top. 



4742. Green-Bigelow Water Bottle 



Although seldom used by the Coast and Geodetic Survey, the Green-Bigelow water 

 bottle is an efficient ins-trument which has the additional advantage of embodying a 

 reversing thermometer holder. The water cylinder is hinged on one side of a heavy 

 frame, the hinges incorporating stopcocks' at the upper and lower ends of the cylinder. 

 A reversing thermometer holder is pivoted on the frame so that it will capsize when 

 released. A mechanism is provided to hold the stopcocks of the water cylinder open 

 and the thermometer holder upright while the instrument is lowered. When the 

 desired depth is reached, a messenger, that fits around the sounding wire, is released 

 at the surface and descends along the wire until it strikes a trigger on top of the instru- 

 ment. This releases the reversing thermometer holder and allows the water cylinder 

 to fall on its hinges, closing the stopcocks. The water cylinder contains a petcock 

 through which the water sample may be drawn off into a hydrometer jar. 



4743. Multiple Sea Sampler 



The multiple sea sampler is a new instrument that promises to be a valuable 

 accessory in oceanographic surveys. It comprises six sample bottles arranged so that 

 they trip and take water samples at different selected depths from a vessel underway. 

 It is limited in use to depths less than 82 fathoms. 



465382—44 28 



