136 



Scientific Proceedings (29). 



portion of acid substituted for ammonia absorption during the 

 second aeration period. In the sixth determination (Group B) 

 aeration was carried in the same manner through a third period 

 of five hours, or fifteen hours in all. Approximately fifth-normal 

 sulfuric acid was used for the absorption of the ammonia. Congo 

 red was used as the indicator. Our results in the first series of 

 tests are given in Table I. 



Table I. 



First Series. Groups A-C. 

 Pure, crystalline ammonio-magnesium phosphate, 1 0.05-0.5 gram. Sodium car- 

 bonate, 1-4 grams. Total periods of aeration, 5-15 hours. Loss of ammonia ; maxi- 

 mum, 48.1 per cent.; minimum, 31. 1 per cent. 





a 



0 







Volume of Standard Acid Solution Required to Neutralize. 





roup 



rt 



° 6 

 SZ 



?nt 



•ESI 



We* « 



After Aeration. 



If All NH S 

 Had Been 



'a -a 



2 S "1 



O 



tf 



'« rt Jz 



^° 











E J S 



V 



5 Hrs., 



5 Hrs., (2) 



5 Hrs., (3) 



Total, 



Liberated, 2 



< ft. 





Q 







c.c. 



c.c. 



c.c. 



c.c. 



c.c. 





A 



I 



0.05 



1 



0.6 







0.6 



I.05 



42.9 





2 



O. I 



1 



1.2 







1.2 



2.05 



41.5 





3 



0.2 



1 



2.4 







2.4 



4. 10 



41.5 





4 



0.3 



1 



4.2 







4.2 



6.15 



31-7 



B 



5 



0.4 



4 





0.55 





4-65 



8.25 



43-6 





6 



o-S 



4 



4.6 



I.20 



1.30 



7.10 



10.30 



3i-i 



C 



7 



0-5 



1 



4-3 



I.05 





5-35 



10.30 



48.1 





8 



0.5 



2.5 



5-i 



0.80 





5.90 



10.30 



42.7 





9 



0.5 



4 



5.6 



O.65 





6.25 



10.30 



39-3 



The results in Table I show that 1 gram of sodium carbonate 

 was unable, after five hours of very strong aeration, completely to 

 eject the ammonia from 50 milligrams of the triple phosphate. 

 The data for Groups B and C show that, after ten hours' aeration 

 of 0.4 or 0.5 gram samples of triple phosphate with 1 to 4 grams 

 of sodium carbonate, large proportions of ammonium were undis- 

 turbed in the crystalline material. Even after fifteen hours' aera- 

 tion of a 0.5 gram sample of the phosphate with 4 grams of sodium 



1 NH 4 MgP0 4 , 6H 2 0. A pure crystalline powder obtained from Eimer and Amend. 

 The theoretical content of nitrogen is 5.707 per cent. The average result of seven 

 closely concordant determinations of nitrogen content by the Kjeldahl method was 

 5.727 per cent. (5.697, 5.766, 5.780, 5.669, 5.725, 5.725, 5.725). 



2 Seven determinations of the volume of our standard acid solution that was re- 

 quired to neutralize the ammonia liberated in the Kjeldahl process from 0.5 gram sam- 

 ples of the triple phosphate used in this series gave the following results (c.c. ) : 10.25, 

 10.40, 10.40, 10.20, 10.30, 10.30, 10.30, or an average of 10.30 c.c. 



