450 EXPERIMENT STATION RECORD. 



uutil after the second reading. The decision arrived at was tlnit these 

 methods shoukl go into effect immediately after the first favorable action, 

 provided the committee charged with testing the methods makes known 

 the results to all members of the association at least 2 months before 

 the meeting at which the method is to be first voted upon. By this 

 means all will have an opportunity to test the method thoroughly dur- 

 ing the first year, and the association will be iii i)osition to take intelli- 

 gent action at the second and final reading. 



Professor Pfeiffer presented a paper upon the determination of phos- 

 phoric acid in precipitates/ previously published.^ It has been 

 assumed that the phosphoric acid in precipitated phosphates was in 

 the form of dicalcic phosphate (reverted). The author found that aside 

 from dicalcic phosphate the precipitates apparently contained consid- 

 erable amounts of pyrophosphates, and that solution in concentrated 

 hydrochloric acid did not give all of the phosphoric acid in the mate- 

 rial. It was found necessary to use nitric acid in addition to hydro- 

 chloric acid in order to completely convert the pyrophosphoric acid into 

 a form which magnesia mixture will precipitate. 



A general discussion of the paper followed, at the close of which 

 Professor Pfeiffer offered the following resolution, which was subse- 

 quently adopted at the first reading: 



(1) It is to be desired that in the sale of precipitated phosphates a 

 guaranty be given for the phosphoric acid jjresent in the form of dical- 

 cium phosphate (citrate-soluble). 



(2) The committee on fertilizers is directed to test the methods for 

 the determination of citrate-soluble phosphoric acid (dicalcium phos- 

 phate) in precii)itated phosphates. 



Professor Pfeiffer was followed by Professor Emmerling, of Kiel, 

 with a paper on the sand content of certain commercial feeding stuffs. 

 He presented a table showing the sand content of peanut meal, peanut 

 cake, cocoanut cake, palm-nut cake, palm nut meal, linseed cake, rape 

 cake, rice feed, and rye bran as determined by a number of stations. 

 He suggested a classification for feeding stuffs, according to their sand 

 content, into good, medium, and bad, attempting to fix the limits to the 

 sand content for each of these classes. For example, for peanut meal 

 1 per cent or less of sand would be considered as "good," from 1 to 2 

 per cent as "medium," and over 2 per cent as "bad." 



After considerable discussion it was decided to postpone definite 

 action with reference to this classification until the next meeting. 



At about 3 p. m. the association adjourned for the day. After par- 

 taking of a dinner prepared for them, some of the members visited the 

 Freseuius laboratory and the local experiment station, while others 

 returned to the " Kurhaus " park where a special program of music, 



' This product, precipitated phosphates, is not fonnd on the market in this country 

 to any extent. 



2Laudw. Vers. Stat., 47 (1896), No. 4-5, pp. 357-360. 



