PROCESS 483 



retorts and condensers used by the water laboratory of the Bu- 

 reau of Chemistry are shown in Fig. 39. The retorts having 

 been previously rinsed with distilled water, receive 500 cubic 

 centimeters of the liquid to be tested for ammonia, together with 

 a few pieces of recently ignited pumice stone, to prevent bump- 

 ing, and five cubic centimeters of the 20 per cent, 

 sodium carbonate solution to render the contents alka- 

 line. The water is raised to the boiling-point and with gentle 

 ebullition 50 cubic centimeters of distillate collected. The dis- 

 tillate is conveniently collected in a color-comparison cylinder 

 of thin white glass and flat bottom, about two and a half centi- 

 , meters in diameter, and marked at 50 and 100 cubic centimeters. 

 Two cubic centimeters of the nessler reagent are added, and if 

 ammonia be present a yellowish-brown color will be developed, 

 the intensity of which is matched by taking portions of the am- 

 monium chlorid solution, diluting to 50 cubic centimeters with 

 pure water and treating with the same quantity of the nessler 

 reagent. The process is repeated until a distillate is obtained 

 which gives no reaction for ammonia. The sum of the quan- 

 tities obtained in the several distillates gives the total amount 

 of ammonia in the 500 cubic centimeters of the water. In most 

 cases practically all the ammonia is obtained in three or four 

 portions of the distillate. 



Albuminoid Ammonia. The residue from the process just 

 described is employed for the purpose of determining the albu- 

 minoid ammonia. Two hundred grams of potassium hydroxid 

 and eight grams of potassium permanganate are dissolved in 

 1000 parts of distilled water. Fifty cubic centimeters of the 

 solution are placed in a porcelain dish with 100 cubic centimeters 

 of distilled water and evaporated to 50 cubic centimeters. This 

 liquid is placed in the retort and the distillation resumed and 

 continued until an ammonia-free distillate is obtained. The total 

 albuminoid ammonia is determined by taking the sum of the 

 quantities in the several distillates. 



Mason varies the nesslerizing process from the above in the 

 following detail : 96 



M Examination of Water, 3rd Edition, 1906 : 56. 



