1.805 (chlorinity %p) . Some other person should 

 check all comjjutations on the D-Sheet and sign 

 off in the checked hy block. The D- Sheet is filed 

 in the Oceanographic Station Folder with the 

 A-Sheet and other oceanographic station data. 



1-15 Securing the Apparatus After Com- 

 pleting the Titration. — After the analyses of 

 a station have been completed, or a day's work 

 has been finished, the apparatus must be secured. 

 The pipette and burette will last longer between 

 cleanings if, whenever they are not ni use, they 

 are kept filled. Fill the pipette with sea water 

 and the burette with silver nitrate, and check 

 to see there are no air bubbles. Set the upper 

 leveling stopcock of the burette to the overflow 

 position. This will allow expansion of solution 



in the burette in the event of temperature 

 change. Apply a pinchclamp to the tubing from 

 the silver nitrate botttle. Place an empty beaker 

 below the delivery stopcock of the burette to 

 catch any leakage. Clean the table with sea 

 water, and wash and dry all beakers, magnetic 

 stirring bars, pickup, and stirring rods. Do not 

 leave unwashed any apparatus that has been 

 used. 



1-16 Maintenance and Repair of Appara- 

 tus. — The Knudsen titration apparatus requires 

 little maintenance except routine cleaning. It is 

 almost impossible to repair broken burettes or 

 pipettes. Even when done by experienced glass- 

 blowers, they must be recalibrated. It is better 

 to use a new piece of apparatus. 



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