RECENT WORK IN AGRICULTURAL SCIENCE. 



AGRICULTURAL CHEMISTRY— AGROTECHNY. 



[The sampling of fertilizers, soils, foods, water, feeding stufEs, and mis- 

 cellaneous materials], L. Foukton (f'Jstac. Agr. Cent. [Mcxic()'\, Circs. 27, pp. 

 //; 28, pp. rj; 29, pp. 6; 30, pp. 5; 81, pp. 7; 32, pp. 8).— A description of tlie 

 iiK'tliods of sniiii»liiig utilized at the Estacion Aji;ri(*oI;i CV'ntral of Mexico. 



The interpretation of color values obtained by Lovibond's tintometer, 

 A. W. Knapp {Jour. Soc. Chem. Indus., 29 {1910), No. 23, pp. 131,3, jf .?////) .—The 

 author points out that where two or three standard glasses are utilized for de- 

 termining the color of fluids, solids, etc., no allowance is made for the stoppage 

 of white light. He holds that this should be taken Into consideration when 

 recording results. 



Methods for the rapid examination of water, A. DanIo {Chem. Ztg., 3Jf 

 {I9tit), No. 119, pp. JO.'jy, lOGR). — This is a discussion and description of rapid 

 niclliods for detecting and determining nitrites, nitrates, chlorids, annnonia, 

 magnesium, sulphates, calcium, total carbon dioxid, organic matter, and Bacillus 

 colt. Some of these methods are modifications of the standard methods in pres- 

 ent use for water analysis. 



The determination of free carbon dioxid in water, J. Tillmans and O. 

 ITeuiu.ein {Ztsehr. Untersnch. Nahr. u. Gemissmth, 20 {1910), No. 10, pp. 617- 

 631, figs. 2). — It appears from this work that the free carbon dioxid in water can 

 be accurately estimated with limewater and other alkalis, using phenolphthalein 

 as an indicator, providing certain precautionary measures are taken to prevent 

 the loss of the carbon dioxid. Sulphates, chlorids, nitrates, and bicarbonates of 

 the alkalis and alkali earth metals react neutrally toward this indicator, while 

 rosolic acid is neutral to sulphates, chlorids, and nitrates of the alkalis and 

 alkali earth metals, but reacts strongly alkaline with their carbonates and bicar- 

 bonates. Accoi'dlng to this, Pettenkofer's qualitative test, which utilizes rosolic 

 acid for detecting free carbon dioxid can not be used with certainty for 

 small amounts of free carbon dioxid nor for large amounts when much bicar- 

 bonate is present. The quantitative determination of free carbon dioxid in 

 water by titration with alkali or borax solution, using rosolic acid as indicator, 

 yields inaccurate I'esults. 



Dissolved oxygen as an index of pollution, G. A. Soper and P. B. Parsons 

 {Abs. in Science, n. ser., S3 {1911), No. SJ/li, p. 3^). — The determination of the 

 dissolved oxygen has been found to be a good index for determining the pollu- 

 tion of water by sewage. The authors state that they have perfected a field 

 method for this purpose. 



The use of calcium carbid for determining moisture, I. Masson {Chem. 

 News, 103 {1911), No. 2670, pp. 37, 38).— The author points out the advantages 

 of using calcium carbid for determining water (E. S. R., 22, p. 513) in various 

 agricultural products as, for instance, wool, cotton, tobacco, flour, wood pulp, 

 paper, etc. 

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