CONVENTION OF OFFICIAL AUKICITLTURAL CHEMISTS. 429 



phosphorus. Uniform results for total ])lios])li(irus were obtained V)y the magnesium 

 nitrate and Neuuianu methods. 



The method finally adopted as giving best results in the determination of inorganic 

 phosphorus consisted in extracting 5 gm. of the sample with 125 cc. of 0.2 per cent 

 hydrochloric acid, the mixture being shaken vigorously for 15 minutes, decanting 

 through a filter paper, and washing the residue with water until 500 cc. of filtrate 

 was C'btained; neutralizing 200 cc. of the filtrate with ammonia, using litmus as an 

 indicator; adding 10 gm. of ammonium nitrate; warming the solution to 65° C, and 

 adding 2 cc. of nitric acid and 25 cc. of neutral ammonium molybdate, the solution 

 being kept at 65° for 15 minutes and filtered after 1 hour. After ignition and puri- 

 fication by dissolving in dilute nitric acid the phosphorus was weighed as magnesium 

 pyrophosphate. 



This article has also appearetl in Bulletin 238 of the \ew York State Station, and 

 an abstract setting forth more fully the results obtained by the use of these methods 

 is given on page 496. 



DETERMINATION OF NITROCiEN. 



The referee reported further tests of methods for determining- avail- 

 able organic nitrogen in fertilizers. A change in the neutral perman- 

 ganate method providing for the use of 2 gm. of material in the case 

 of mixed fertilizers, and as heretofore an amount containing approxi- 

 mately 0.075 gm. of nitrogen in concentrated goods was approved. 

 Further stud}" of methods for available nitrog-en was recommended. 

 A paper on the electrolytic reduction of nitrates was read. 



Report of referee, F. W. Morse. — Eight laboratories cooperated in testing modi- 

 fications of the alkaline permanganate method in comparison with the neutral per- 

 manganate method for determining available organic nitrogen as used last year. 

 Preliminary work with the alkaline i^ermanganate method showed the necessity of 

 a fixed amount of distillate and the probable advantage of a larger volume of solution. 

 Samples of dried blood and cotton-seed meal were sent out with the request for tests 

 of 3 modifications of the permanganate method. 



Nine analysts reported on total nitrogen and 8 on the methods for available nitro- 

 gen. The determinations of total nitrogen agreed closely. The percentages of total 

 nitrogen recovered from blood as available were 86.5 by the neutral method, 63.4 by 

 the alkaline method as given in the report of the referee last year, and 69.4 by the 

 alkaline method modified by the use of 150 cc. of the alkaline permanganate solution 

 and distilling off 100 cc. The corresponding percentages in the case of cotton-seed 

 meal were, respectively, 91.6, 46.1, and 58.1. 



The referee recommended that in the neutral method a 300 cc. low-form Griffin 

 beaker be used and that 2 gm. of material be taken if the sample is a mixed fertilizer, 

 and also that tl.e study of methods for the determination of available organic nitro- 

 gen be continued. 



The electrolytic reduction of nitrogen in metallic nitrates, S. H. Sheih. — 

 The electrolytic reduction of nitrates to ammonia, as described by Easton (see p. 444), 

 was tried b}' Sheib on chemically pure and commercial sodium nitrate and or. potas- 

 sium nitrate with results stated by him to be far from satisfactory 



SEPARATION OF NITROGENOUS BODIES. 



The referee, L. L. Van Slyke, reported investig-ations on the sepa- 

 ration of nitrogenous bodies in milk and cheese, giving methods for 

 15293— No. 5—04 2 



