282 Report of the Chemical Department of the 



monium molvbdaie was prepared by addition of ammonia to the 

 ordinary molybdic solution, using- litmus as an indicator. 



Preliminary estimations showed that forty hours' extraction was 

 entirely unnecessary. Three hours, the time required to thor- 

 oughly wash the residue, gave nearly as high total soluble phos- 

 phorus as forty hours. In the next table are presented results 

 secured by the following methods: 5 grams of the sample was 

 vigorously shaken with 125 cc. of the extracting reagent for 15 

 minutes; the mixture was then allowed to settle, was decanted 

 through a filter paper into a 500 cc. flask and the residue washed 

 with water until about 500 cc. of filtrate had been collected. 

 200 cc. of the filtrate was next neutralized with ammonia, using 

 litmus as indicator, and 10 grams of ammonium nitrate added. 

 The solution was then warmed to 65° C. and, in the case of the 

 water and hydrochloric acid extracts, 2 cc. of 1.26 nitric acid and 

 25 cc. neutral ammonium molybdate were added. To the acetic 

 extracts 4 cc. 1.20 nitric acid were added. The extracts were 

 allowed to stand fifteen minutes at 65°, were then removed from 

 the bath and after one hour were filtered. The phosphorus was 

 estimated as the magnesium salt. 



Table IV. — Separ.\tion of Forms of Phosphorus using Minimum 

 Amounts of Nitric Acid. 



