IV. WATERS. 



POTABLE WATER. 



TURBIDITY.— TENTATIVE. 



1 REAGENTS. 



(a) Standard turbidity solution. — Weigh out 1 gram of elutriated fuller's earth 

 previously dried and sifted through a 200 mesh sieve. Make up to a liter. If the 

 fuller's earth is of good quality and the proper degree of fineness, this stock solution 

 has a turbidity of 1000. Check the stock solution with a Jackson turbidimeter. 



(b) Turbidity standards. — Prepared by dilution of (a). 



2 DETERMINATION. 



Determine the turbidity of the sample with a Jackson turbidimeter equipped 

 with either candle or electric light. If the turbidity is less than 100, which pro- 

 hibits the use of the turbidimeter, determine by direct comparison with turbidity 

 standards contained in bottles of clear white glass. 



COLOR.— TENTATIVE. 



3 REAGENTS. 



(a) Standard color solu'ion. — Dissolve 1.246 grams of potassium platinic chlorid 

 (PtCl42KCl) and 1 gram of crystallized cobalt chlorid (C0CI26H2O) in a small quan- 

 tity of water, add 100 cc. of concentrated hydrochloric acid and make up to 1 liter 

 with water. This stock solution has a color of 500. 



(b) Color standards. — Prepared by dilution of (a). 



4 DETERMINATION. 



Compare the color of the sample, freed from suspended matter, with color 

 standards in tubes of clear white glass. 



5 ODOR.— TENTATIVE. 



Shake the vessel containing the sample and note the odor. Heat a portion of the 

 sample just to boiling and note the odor. 



6 TOTAL SOLIDS.-OFFICLAL. 



Thoroughly shake the vessel containing the sample and pipette 100 cc. of the un- 

 filtered water into a weighed platinum dish. If the sample contains much suspended 

 matter, shake, pour rapidly into a 100 cc. measuring cylinder, and transfer without 

 delay to a weighed platinum dish; evaporate to dryness and heat to constant weight 

 at 105°C. In the case of highly mineralized waters it is advisable to weigh again 

 after drying at 1S0°C. 



7 SOLIDS IN SOLUTION.— OFFICIAL. 



Allow the sample to stand until all sediment has settled, and filter if necessary 

 to secure a perfectly clear liquid. Occasiona ly a clear filtrate can only be obtained 

 by the use of alumina cream but this should be avoided if possible. Evaporate 100- 



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