ANALYSIS OF BASIC SLAGS 203 



of digestion, the apparatus devised by the author may be used. 52 



176. Solutions Employed in the Wagner Method. i. Am- 

 monium Citrate. In one liter there should be exactly 150 grams 

 of citric acid and 27.93 grams of ammonia, equivalent to 23 

 grams of nitrogen. The following example illustrates the prep- 

 aration of 10 liters of the solution: In two liters of water and 

 3.5 liters of eight per cent, ammonia, 1500 grams of citric acid 

 are dissolved and the cooled solution made up exactly to eight 

 liters.* Dilute 25 cubic centimeters of this solution to 250 cubic 

 centimeters and treat 25 cubic centimeters of this with three 

 grams of calcined magnesia and distill into 40 cubic centimeters 

 cf half-normal sulfuric acid. Suppose the ammonia nitrogen 

 found corresponds to 20 cubic centimeters of fourth-normal soda- 



ATM. *u u*. 1-4. ,20.0X0.0035X8000 



lye. Then in the eight liters are contained - 



=224 grams of ammonia nitrogen. In order to secure in 

 the 10 liters the proper quantity of ammonia there must be added 

 two liters of water containing 230 224=six grams of nitrogen 

 or 7.3 grams ammonia ; viz., 94 cubic centimeters of 0.967 specific 

 gravity. 



2. Molybdate Solution. Dissolve 125 grams of molybdic acid 

 in dilute 2.5 per cent, ammonia, avoiding a large excess of the 

 solvent. Add 400 grams of ammonium nitrate, dilute with water to 

 one liter and pour the solution into one liter of nitric acid of 1.19 

 specific gravity. Allow the preparation to stand for 24 hours at 

 35 and filter. 



3. Magnesia Mixture. Dissolve no grams of pure crystallized 

 magnesium chlorid and 140 grams of ammonium chlorid in 700 

 cubic centimeters of eight per cent, ammonia and 130 cubic centi- 

 meters of water. Allow to stand several days and filter. 



177. Analysis of Basic Slags by the Method of the German 

 Agricultural Experiment Stations. The methods of determining 

 the fertilizing value of basic slags (Thomas Meal) have been 

 studied by a committee of the German experiment stations. 53 



53 Principles and Practice of Agricultural Analysis, 2nd Edition, 1906, 



1 : 394- 



M Wagner, Bestimmung der zitronensaureloslichen Phosphorsaure in 



Thomasmehlen, 1903. 



