NOTES. 797 



method for humus and humus nitrogen, and to make a study of methods for 

 determining organic carbon and nitrogen in soils. 



A paper on the differences in lime requirement as indicated by the Veitch 

 method, by A. W. Blair and H. C. McLean, brought out that the method may be 

 depended upon within reasonable limits. C. H. Jones described a method for 

 the determination of lime requirement of soils, which consists In rubbing up 

 5.6 gm. of soil with 0.5 gm. of calcium acetate (guarantied reagent), adding 

 enough water to make a stiff paste, mixing, and washing Into a flask, taking 

 care to keep the bulk of the fluid down to 160 cc. After shaking occasionally 

 during a period of 15 minutes, make up to 200 cc, filter, and titrate 100 cc. of 

 clear filtrate with decinormal sodium hydroxid solution. The number of cubic 

 centimeters multiplietl by 36,000 equals the pounds of lime (CaO) necessary 

 for 2,000,000 lbs. of soil. 



The associate referee on nitrogenous compounds in soils reported that lime 

 seems to be the best agent known for the clarification of watery soil extracts 

 in which nitrates are to be determined. The Chamot modification of the phenol- 

 sulphonic acid method in most instances gave better results than the Gill 

 method on the soil alone and in every case where potassium nitrate was added. 

 The association approved the reduction method for nitrates and the method 

 for nitrites and ammonia proposed by the associate referee as used for water. 



W. H. Mclntire and B. E. Curry, the referee and associate referee, respec- 

 tively, on inorganic plant constituents, reported a further and final study of 

 the Schreiber method for SO3, and an additional study of the official method 

 for Fe203 and AI2O3 as extended to the determination of calcium and magnesium. 

 As good results had been obtained during 4 years of study with the proposed 

 molybdate method for iron and aluminum, which includes the determination of 

 calcium, manganese, and magnesium, it was recommended for provisional 

 adoption. Even when the amount of manganese present is many times that 

 which occurs under normal conditions, there is only a slight occlusion. The 

 association voted to extend the official method for iron and aluminum to 

 include the determination of calcium and magnesium when only small amounts 

 of manganese are present. It appears that the official method for sulphur can 

 be simplified considerably if certain modifications are introduced into the pro- 

 cedure as recommended by Patten. 



Results of a comparative and cooperative study of the zinc chlorid and iodin 

 methods for lime sulphur as proposed by Harris (E. S. R., 25, p. 414) were 

 reported by S. D. Averitt, the referee on insecticides. Another paper, dealing 

 with the same methods, was submitted by R. C. Roark, and a method for the 

 analysis of lime-sulphur solution was also presented by S. D. Averitt, with 

 which an analysis can be made sufficiently accurate for commercial work in 

 about 2 hours. The whole question of the analysis of the lime-sulphur solu- 

 tion was referred to a special committee consisting of W. F. Hillebrand, C. S. 

 Cathcart, and H. H. Hanson, which is to examine the work presented by 

 referees during the past 3 years. The referee also reported on the determina- 

 tion of water-soluble arsenic in lead arsenate, recommending that the method 

 submitted be adopted as provisional and the present provisional method 

 dropped. 



The referee on water reported satisfactory results of a study of the proposed 

 methods for strontium, iodin, and bromin, but these will be studied further. 

 The remaining methods proposed 2 years ago were made official. 



The report of the committee on the availability of phosphoric acid in basic 

 slag, C. B. Williams, chairman, consisted chiefly in showing the progress made 

 in the pot experiment study of the availability of phosphoric acid in basic 

 slag as compared with that in sodium acid phosphate, double superphosphates, 

 acid phosphate, and finely ground phosphate rock. 



