Bottle, Amber glass, laboratory, metric 



capacity, narrow mouth with ground-in flat 



glass stopper. Capacity 250 ml., 1 liter, 2 



liters. 



Bottle, wide mouth, 3-gallon capacity. 

 Bottle, volatile liquid, ground-on glass cap, 



capacity 500 ml. 



Burette, Schellbach, Automatic Zero, 3- 



way stopcock, capacity 25 ml., 50 ml. 



Pipette, automatic, aba pipettor type ca- 

 pacity 2 ml. 



Pipette, automatic, delivery, NORMAX, 



capacity 50 ml., 100 ml. 



Pipette, Measuring, Mohr, EXAX, Blue 



Line No. 5, capacity 5 ml. 



Pipette, transfer type, NORMAX, Pyrex 



capacity 1 ml., 5 ml., and 10 ml. 

 Reader, Burette meniscus. 



13-40 Setting Up the Apparatus. — Numer- 

 ous pipettes are rsquired for the various steps 

 in the Winkler method. A 10- and a 5-ml. 

 pipette are required for the standardization of 

 the sodium thiosulfate solution. A 50- or 100- 

 ml. automatic volumetric pipette is required 

 for drawing and measuring tlie treated sea water 

 sample for titration. One- and two-ml. pipettes 

 are required for the blank run and for the 

 treatment of the sea water samples. All of the 

 pipettes should be of at least EXAX quality, 

 except for the transfer of potassium dichromate 

 solution in the standardization procedure, where 

 NORMAX quality is required. 



The pipettes used on U. .S. Navy surveys for 

 delivery of the reagents required to treat the 

 sea water samples are the automatic-measuring 

 type, delivering 1 ml. each of manganous chlo- 

 ride and alkaline iodide, and 2 ml. of hydro- 

 chloric acid. 



The burette used for the titration is a Schell- 

 bach automatic zeroing, 3-way stopcock, 25 or 

 50 ml. delivery capacity. 



Before any of the pipettes and the burette 

 are used they must be cleaned and the stopcocks 

 lubricated in the manner described in sections 

 13-14 and 13-15. All other apparatus and 

 glassware should be kept very clean. Washing 

 with a good detergent soap and numerous rinses 

 with fresh water usually will be adequate for 

 most glassware. 



The titration apparatus may be set up in 

 much the same manner as that used for chlo- 

 rinity analysis. The background behind the 

 burette should be painted flat white and a 

 fluorescent titration lamp should be rigged be- 

 hind the burette. 



Figures 13-7 and 13-8 show schematic ar- 

 rangements for the automatic 50-ml. pipette 

 and the burette. Clamp the glassware to the 



132 



r 



r 



Table lS-7. Automatic pipette assembly. 



Figure 13 



Q 



r 



PRESSURE SULB 



^ 



C 



Automatic burette assembly. 



H. O. 607 



