432 EXPERIMENT STATION RECORD. 



POTASH. 



The report of the referee, G. S. Fraps, dealt with the determina- 

 tion of water in kainit and mixed fertilizers and the volumetric method 

 for potash. In the determination of potash the modified method 

 which, provides for the use of an acid solvent was found to be more 

 satisfactory than the official method. Experiments were made to 

 ascertain how much potash would be removed from insoluble sili- 

 cates by the modified method, from which the conclusion was drawn 

 that this method does not open the way for the potash-bearing- silicates 

 for tillers, as the amount of potash that could be so added is insignifi- 

 cant. While believing that the modified method is accurate, the ref- 

 eree hesitated to give it his unqualified indorsement, inasmuch as the 

 laws of 27 States require potash to be soluble in water. The referee 

 recommended that the volumetric method be further studied with par- 

 ticular reference to its use in soil analysis, which was approved by 

 the association. The referee for next year was also instructed to stu< Ly, 

 in the determination of potash in mixed fertilizers, incineration at low 

 temperature and solution in dilute acid. 



The discussion showed a considerable difference of opinion as to the 

 availability of organic potash and the advisability of using an acid 

 solvent in determining potash in mixed fertilizers. It was suggested 

 that the different forms of potash be determined and stated. 



A paper on the use of acetic and oxalic acids for extracting the 

 charred material in preparing ash, by B. L. Hartwell and J. W. Kel- 

 logg, was read by title. The amount of crude ash was generally 

 greater when oxalic acid was used. 



DETERMINATION OF NITROGEN. 



A letter from the referee, F. W. Robinson, stated that there were 

 no results ready to report on this subject. 



By vote of the association the referee for next year was instructed 

 to stud}^ the addition of \ to f gm. of copper sulphate after digestion 

 with sulphuric acid and potassium sulphate in the determination of 

 nitrogen by the official Gunning method. 



R. J. Davidson proposed a change in the method of standardizing the 

 hydrochloric acid used in the determination of total nitrogen. 



SEPARATION OF NITROGENOUS BODIES. 



The report on milk and cheese proteids was submitted by the referee, 

 R. Harcourt. The method elaborated by Van Slyke and Hart for the 

 separation of nitrogenous bodies in cheese was subjected to collabora- 

 tive tests. Eight chemists reported results which formed the main 

 part of the report. The referee recommended that the work be con- 

 tinued, special attention being given to the problem of making a com- 



