CONVENTION OF OFFICIAL AGBICULTURAL CHEMISTS. Ill 



uliit(Hl w itli active .soil. Under uniform conditions a,s regai'ds moist- 

 ure, temperature, and plant food, .soils showed a variable rate of 

 nitrification attributed to .stage.s in the life history of the nitrifjdng 

 oro-anism.s. Differences in the power of soils to induce nitrification in 

 sterile soil provided with nitrogenous substances and kept under favor- 

 a})le conditions w'ere con.sidered dependent upon an increase in the 

 number of organisuLS pre.sent and upon an increase in their activit}. 

 Variations in the comparative rate of nitrification of cotton, seed meal 

 and annnonium sulphate in .sterile soil inoculated with difi'erent soils 

 pointed to variations in the organism.s themselves. Rased upon the 

 work recoided in detail in the paper, methods were proposed for 

 determining the relative nitrifying power of soils. 



A paper on ''A Quantitative Method for Determining the Acidity 

 of Soils/' by C. G. Hopkins, W. H. Knox, and J. H. Pettit, wa.s read 

 1)3' Dr. Hopkins. The method, which is based upon the reaction 

 occurring when solutions of mineral salts are added to acid soils, ha.s 

 been used in pot and field experiments at the Illinois Kx])eriment Sta- 

 tion during the past year, and "it is asserted with confidence that it 

 can be relied upon to give trustworthy results." The addition of lime 

 to soils in ({uantities indicated by the method was found to neutralize 

 the acidit}'. The advantages of determining accurately the quantity 

 of lime to apply to acid soils were pointed out. The method of deter- 

 mining acidity used in the Bureau of Soils was described by F. P. 

 Veitch. The influence of .soil and meteorological conditions upon the 

 yield and character of crops was discu.sscd by H. W. Wiley, who con- 

 cluded his remarks as follows: '"Agricultural chemistry, pa.ssing from 

 having determined what the soil is and what plants are and how fer- 

 tilizers can be made and applied, is now advancing to a still higher 

 plane of investigation, to determine how the .soil shall be made maxi- 

 miun in production and how the conditions of growth shall secure the 

 maxinumi of desirable qualities." 



The reconnnendations were adopted by the association that the 

 N-200 hydrochloric acid method be given further trial, that samples 

 for the determination of available phosphoric acid and potash be taken 

 to a greater depth than at present, that virgin soils be used in inves- 

 tigations, that the determination of the acidit}' of soils be referred to 

 the referee, and that methods for the anal3'sis of alkali soils be further 

 studied, with a view to ascertaining the most desirable amount of soil 

 and the amount of water to be used in dissolving the soluble .salts. 



DAIRY PRODUCTS. 



The referee on dairy products, G. W. Cavanaugh, reported on work 

 done in his laboratory during the year on the determination of al})umin 

 in milk. On fresh .samples the present official and provisional meth- 

 ods gave concordant results. On milk preserved with formalin the 



