EXPERIMENT STATION RECORD. 



Vol. 35. Abstract Number. No. 9. 



RECENT WORK IN AGRICULTURAL SCIENCE. 



AGRICULTURAL CHEMISTRY— AGROTECHNY. 



Catalysis and its industrial applications, Fl .Tobling (London: J. d A. 

 Churcfiill, 1916, pp. VI 1 1 +120, figs. 12).— The subject matter of this volume 

 appeared originally in the Chemical World in 1912. The topics discussed are 

 catalysis in general; sulphuric acid manufacture; industrial chlorin, salt cake, 

 and sulphur recovery ; fixation of atmospheric nitrogen ; surface action ; liydro- 

 genation ; dehydrogenation and oxidation ; and dehydration, hydrolysis, etc 



Hydrogen electrode potentials of phthalate, phosphate, and borate buffer 

 mixtures, W. M. Clabk and H. A. Lubs {Jour. Biol. Chem., 25 {1916), No. 3, 

 pp. 479-510, figs. 2). — The authors have studied the hydrogen electrode poten- 

 tials of the following mixtures at 20° C. : Acid potassium phthalate — hydro- 

 chloric acid ; acid potassium phthalate — sodium hydroxid ; acid potassium 

 phosphate — sodium hydroxid; boric acid+potassium chlorid— sodium hydroxid; 

 boric acid — sodium hydroxid ; and potassium chlorid at 25° — hydrochloric acid. 

 The concentration of the first component was in all cases maintained at 

 5/100-molar sti'ength. 



It is suggested that " a temperature correction should be included in the 

 barometric correction of hydrogen electrode potentials. The application of 

 this, together with a consideration of several theoretical and experimental 

 difficulties, leads to the conclusion that in biochemical work the tenth-normal 

 KCl-calomel electrode should be given the provisional and somewhat arbitrary 

 value 0.3385 between 18 and 30° when referred to the potential of the ' normal 

 hydrogen electrode.' By applying the full barometric correction and the above 

 value of the tenth-normal calomel electrode the Ph values of the various mix- 

 tures were calculated, and the compositions given which furnish mixtures 

 differing by intervals of 0.2Pif for use as comparison solutions in the colori- 

 metric determination of hydrogen ion concentrations." 



The system of " buffer " mixtures described has been shown to be simpler 

 to prepare and easier to standardize than those now in common use. "Acid 

 potassium phthalate solutions possess properties which make them comparable 

 with or better than ' standard acetate ' and similar solutions for standardizing 

 hydrogen electrode systems." 



A new "hot-air" Teclu burner, P. Vekbeek (Chem. Ztg., 39 {1915), No. 

 148-I49, p. 948, figs. 5 ) . — A new laboratory burner in which the admitted air is 

 heated before it is allowed to mix with the gas and in which the width of the 

 flame can be easily controlled by a simple arrangement is described in detail. 

 An economy in both heat and gas is claimed for the improved burner. 



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