Vi CONTENTS 



stannic phosphate; Phosphoric acid soluble in ammonium citrate; Arbi- 

 trary determination .of reverted phosphoric acid; Theory of revision; 

 Influence of movement; Digestion apparatus for reverted phosphates, 

 Comparison of results ; Huston's mechanical stirrer ; Precipitation of 

 the water and citrate-soluble phosphoric acid; Veitch's method for 

 available phosphoric acid; Availability of phosphatic fertilizers. 



Direct Weighing of the Phosphomolybdate Precipitate, pp. 122-130. 

 Method of Hanamann; Method of Lorenz; Method of Woy; Berju's 

 modification ; Method of Graftiau ; Method of Pellet ; Cladding's modifica- 

 tion, 



Volumetric Determination of Phosphoric Acid, pp. 130-178. Classifica- 

 tion of methods ; Uranium method ; Precipitation of phosphates in pres- 

 ence of citrate ; Magnesium citrate solution ; Filtration and washing ; 

 Standard solution of uranium nitrate ; typical solution of phosphoric- 

 acid ; Titration of uranium solution ; Determination of phosphoric acid 

 in superphosphates ; Determination of soluble and reverted phosphoric acid ; 

 Conclusions ; Pemberton's volumetric method ; Alkalimetric estimation of 

 phosphoric acid; Comparison of weighing and titrating methods; Esti- 

 mation of phosphoric acid as a lead compound ; Water-soluble phosphoric- 

 acid; Estimation of phosphoric acid in the presence of iron ; Methods of the 

 international steel standards committee ; Calculating results ; The silver 

 method. 



Technical Determination of Phosphoric Acid, pp. 179-189. Desirability 

 of methods ; Reagents ; Manipulation ; Citrate method ; Uranium method ; 

 Determination of phosphoric acid in basic slags ; Determination of phos- 

 phoric acid in superphosphates ; Determination of free acid in phosphates ; 

 Ostersetzer's method. 



Basic Phosphatic Slags, pp. 190-223. Uses of basic slag; History and 

 manufacture ; Quantity made ; Process of manufacture ; Composition 

 of slag phosphate ; Molecular structure ; Solubility ; Solvents ; Method 

 of estimation; Method used at the Halle agricultural station; Dutch 

 method ; Estimation of citrate-soluble phosphoric acid ; Wagner's method ; 

 Method of the German agricultural experiment stations ; Preparation 

 of the citric acid extract ; Direct precipitation method ; German method 

 for slags rich in silicic acid ; Bottcher method ; Separation of silicic acid ; 

 Estimation of total phosphoric acid ; American methods ; German manu- 

 facturer's method ; Estimation of lime ; Detection of adulteration. 



Determination of Other Constituents in Natural Phosphates, pp. 224- 

 260. Water and organic matter ; Carbon dioxid ; Soluble and insoluble 

 matter ; Silica and insoluble bodies ; Loss of silica and fluorin ; Esti- 

 mation of lime; Ammonium oxalate method; Method of Immendorff; 

 Estimation of iron and alumina; The acetate method; Method of Hess; 

 Method of E. Glaser; Jones' variation; Crispo's method; Variation of 



