RECHXT WORK I\ ACRICULTl'RAL SCIHXCL 



AGRICULTURAL CHEMISTRY— AGROTECHNY. 



Small encyclopedic dictionary of agricultural chemistry, M. Passon 

 (Kleines Handivortcrbuch dcr AgrikuJturvhemic. Lciimic, 1910, pp. IT+Jfl5, 

 figs. 305 ) . — According to the preface this vohime is to serve the purpose of ready 

 reference, particularly in experiment stations where a large library is lacking. 

 Notable features in the work are the descriptions of the various chemical meth- 

 ods, and data relating to animal physiology and nutrition and the various feed- 

 ing stuffs. 



Electrolytic reduction of nitric acid, H. E. Patten {Trans. Amer. Elecirochem, 

 Soc, 12 (1907), pp. \323-398, figs. 9). — According to earlier investigations, in re- 

 ducing nitric acid with a platinum cathode hydroxylamin is obtained along with 

 nitrogen gas and ammonia. Xo nitrate is produced. Tlie effect of the cathode 

 material on the yield of ammonia has been investigated, but little attention 

 hitherto paid to cathode polarization. The author, in the laboratory of the 

 Bureau of Soils of this Department, studied the conditions accompanying the 

 various yields of ammonia and of hydroxylamin. The initial electrode single 

 potentials were noted, and measurements repeated throughout the electrolysis. 

 The effect on the yield of different conditions was determined, such as the con- 

 centration ; the use of a copper cathode with a porous diaphragm and lead anode 

 in dilute sulphuric acid ; current density : temperature ; the presence of copper 

 sulphate: and tlie use of different cathode materials. The reducibility of hy- 

 droxylamin at the copper cathode and the reduction of nitratd with a copper 

 cathode and platinum anode were determined. 



The author concludes from his experiments that an increase iu the concentra- 

 tion of the acid increases the yield of ammonia and decreases the hydroxylamin, 

 using a copper cathode in dilute sulphuric acid. An increase of current density 

 decreases the ammonia yield with a copper cathode, but increases it with a 

 platinum cathode. The effect of temperature on the yield of ammonia and 

 hydroxylamin is slight. The ammonia yield is increased by the continued depo- 

 sition of copper at the cathode, whether smooth or spongy, or amalgamated. A 

 low cathode discharge accompanies a high yield of ammonia, as does also a low- 

 current density. Nitrogen, either free or as oxids. is given off at both the cop- 

 per cathode and platinum anode. The reduction of nitric acid to ammonia at 

 a copper cathode probably involves the formation of hydroxylamin as an inter- 

 mediate stage. The electrolysis of sodium nitrate at the copper cathode in a 

 sulphuric acid solution reduces all the nitrogen to a form which is not oxidized 

 by potassium pei'mjuigaiiate. 



The electrolytic reduction of nitric acid, II, III, II. E. Patten mhu W. J. 

 McCaughey {Trans. Anicr. Elect rnchcni. Soc, 15 {1909), pp. 535-557, figs. 5; 

 17 {1910), pp. 377-390, figs. .}). — In a second i)aper continuing the above work, 

 the action of oxygen liberated at a plntinum .•mode upon annnonium sulphate in a 

 sulphuric acid solution was studied, and also the reduction of potassium ni- 



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