2-23 PRECAUTIONS FOR HANDLING, 

 STORING, AND TRANSPORTING DEEP- 

 SEA REVERSING THERMOMETERS.— 



Deep-sea reversing thermometers are extremely 

 delicate precision instruments and must be 

 handled with care. They are difficult to man- 

 ufacture and calibrate and are expensive. 

 Their construction is such that it is very easy 

 for the mercury in the main thermometer to 

 become separated so that gas from the bulb is 

 trapped in the capillary, thereby making the 

 thermometer malfunctional. To prevent this, 

 a primary precaution in handling reversing 

 thermometers is never lay a reversing thermom- 

 eter flat. If a reversing thermometer has to be 

 laid on a flat surface, it must always be placed 

 on some object so that it is tilted slightly with 

 the reservoir end down. 



2-24 Reversing Thermometer Carrying 

 Cases. — Special cases are provided for storing 

 and transporting reversing thermometers. 

 Thermometers not in use should always be 

 stored in these cases. The cases are specially 

 designed and are lined with foam rubber. The 

 following precautions must be taken: 



1. Wash the glass jackets of the thermom- 

 eters with fresh water and dry them thoroughly 

 before placing them in the case. Flush out the 

 inside of the jackets of the unprotected ther- 

 mometers with fresh water. 



2. Always place the reversing thermometers 

 upright in the case with the reservoir end domn 

 to avoid separation of the mercury in the main 

 thermometer and subsequent malfunction. 

 Only in the instance where the thermometers 

 will be exposed to air temperatures lower than 

 — 10° C. (14° F.), is exception to this rule per- 

 missible. Then they are stored in the reversed 

 position, since at such low temperatures the 

 mercury in the auxiliary thermometer will va- 

 cate the capillary entirely and contract into 

 the bulb. If stored in the upright position, 

 the mercury will separate leaving gas in the 

 bulb when warmed. 



3. Always store and transport the thermom- 

 eter carrying case in an upright position. 

 Never lay it on the side. 



4. Reversing thermometers stored in carrying 

 cases should always be transported by courier. 

 Unless it is absolutely unavoidable, they should 

 never be shipped by mail, freight, or express 

 unless packed by the manufacturer. 



2-25 Reversing Thermometers Stored on 

 Nansen Bottles. — When at sea, Nansen bottles 

 with attached thermometers should be inverted 

 in the rack after all thermometers have been 

 read in order to prevent the thermometers 

 from remaining in a reversed position. If they 



are not to be in use for periods greater than 2 or 

 3 days, it is recommended that they be removed 

 from the frames and stored properly in the 

 carrying cases. 



2 26 DRAWING AND PRESERVING SEA 

 WATER SAMPLES.— After the Nansen bottles 

 have been removed from the wire they are 

 replaced in their proper position in the rack. 

 The water samples obtained at various depths 

 are then drawn into respective glass bottles 

 and the thermometers are read. These water 

 samples are analyzed for such constituents as 

 salinity, dissolved oxygen content, and various 

 nutrients. As the methods of analysis for each 

 constituent are usually quite different, the 

 volume of sample necessary, type of glass 

 bottle used, time permitted before analysis, and 

 methods for drawing the samples differ. The 

 following directions must therefore be fol- 

 lowed carefully for each type of sea water 

 sample desired. All glass sample bottles to 

 be used are placed in the rack directly below 

 each Nansen bottle. Each sample bottle must 

 be numbered and the number recorded in the 

 proper column on oceanographic log sheet A. 



Before drawing water samples from the 

 Nansen bottle the air vent must be opened to 

 permit the water to drain. The vent screw 

 is located near the top of the Nansen bottle 

 just below the valve. The drain petcock is 

 located just above the bottom valve. 



2-27 Drawing Sea Water Samples for 

 Dissolved Oxygen Content Analyses. — If oxy- 

 gen analyses are desired, the samples for this 

 purpose must be drawn first. Water sam- 

 ples to be analyzed for dissolved oxygen 

 content are preserved in 250-ml. amber reagent 

 bottles with ground glass stoppers. Before 

 drawing the sample, the bottles must be thor- 

 oughly rinsed by adding a small amount of 

 sample water and shaking vigorously. Be 

 sure to pour the rinse water over the glass 

 stopper. Rinse at least twice. 



The addition of Nansen bottle water to 

 the oxygen sample bottle must be performed 

 carefully. To draw the sample from the Nansen 

 bottle, a delivery tube must be attached to the 

 drain petcock. A delivery tube consists of a 

 piece of soft-wall rubber tubing about 5 inches 

 long with a 3-inch glass tube inserted in one end. 

 The exposed end of the glass tube is constricted 

 slightly and is fire-polished smooth. Attach 

 the rubber end to the drain petcock and insert 

 the glass tip to the bottom of the sample 

 bottle. Open the drain petcock very slowly 

 to prevent air bubbles from entering the 

 sample. As the bottle fills the petcock may be 

 opened wider. Be sure that no air bubbles 



H. O. 607 



15 



