AGRICULTURAL CHEMISTRY AGROTECHNY. 113 



A comparison of some qualitative and quantitative methods for carbonates 

 in soils, E. W. Gaitheb {Jour. InduK. and Engin. Chcin., 5 (JOld), No. 2, pp. 

 138-143, figs. ^).— The author fmas that moth<xls which boil soils with mineral 

 acids at 100" C. for determining the carbon dioxid content of the soils are in- 

 accurate as a measure for carbonates in soils, because often the organic matter 

 present in the soil is decomposed by the acid treatment, and results in the 

 evolution of carbon dioxid. This confirms the findings of Marr (PI S. R., 22, 

 p. 511). If, however, the soils are boiled In a partial vacuum at 50" with 

 dilute mineral acids, no decomposition of organic matter talces place, and the 

 evolved carbon dioxid is representative of the carbonates present. 



The litmus paper test, when properly conducted, was found to be the best 

 qualitative test known for determining the presence of native carbonates in soils 

 from humid regions. On the other hand, some soils may give an alkaline 

 reaction not due to carbonate but to the products resulting from the hydrolysis 

 of certain minerals which exist in soils, as pointed out by Cameron and Bell 

 (E. S. E., 17, p. 742). Although the reddening of blue litmus paper may be due 

 to the absorption of the base from hydrolyzed litmus salt, the presence of native 

 carbonates in soils can either prevent this selective absorption, or it may cause 

 an interchange of bases to take place. If a native carbonate, which is capable 

 of being decomposed by weak hydrochloric acid at a low temperature, is present 

 in the soil, it is indicated by the bluing of red litmus paper. If no alkalis or 

 basic materials are present which yield alkaline solutions, a reaction is obtained 

 with blue litmus paper. 



Soils containing substances which redden blue litmus paper have a tendency 

 to the formation of acids or acid salts, which unite with the base absorbed 

 from hydrolyzed litmus and fail to return another base in its stead. This 

 results in the reddening of the indicator even though no hydrogen ions are 

 yielded to a water solution. It is possible that the soil is capable of producing 

 a physiological action which is similar to that produced by stronger acids 

 yielding hydrogen ions to aqueous solutions. 



Polarization before inversion in the examination of molasses by Clerget's 

 method, J. J. Hazewinkel and C. Loukens (Meded. Proefstat. Java-^uikcr- 

 indus., 1912, No. 21, pp. 635-637; Arch. t^uikerhuJus. Ncderland. Jndii', 20 

 (J912), No. 27, pp. 1073-1075).— The method recommended is as follows: One- 

 half of the normal weight of the molasses is taken in a 100 cc. flask ; then 10 

 cc. of a solution of neutral lead acetate is added, filled up to the mark with 

 water, from 3 to 5 gm. of bone black added, shaken, and filtered. The polariza- 

 tion is done in a 200 or 400 mm. tube. 



The freezing point of milk, J. B. Henderson and L. A. Meston (Proc. Roy. 

 8oc. QucensJand, 21^ {1913), pp. 165-180, ph 1). — With a view to determining a 

 reliable method by which the addition of water to milk could be detected, tests 

 were made of the freezing point of milk under a variety of conditions. Results 

 indicated "(1) that the freezing point of pure fresh milk samples from herds 

 of cows in southern Queensland never shows a greater variation than from 

 0.55° to 0.5G° C, the mean being 0.555° (this is exactly in accord with Conti- 

 nental experience) ; and (2) that the freezing point determines with accuracy 

 the proportion of water added to any milk from a herd, and distinguishes v^ith 

 absolute certainty the watered rich milk from the naturally poor milk." 



A new scale for determining* moisture in butter, E. Worker (Ztschr. 

 Untersuch. Nalir. u. GenussmtL, 24 (1912), No. 12, pp. 741, 742, fig. 1).—A 

 description and illustration of the apparatus are given. 



A simple test for the determination of butter fat in butter, J. M. Doran 

 {Jour. Indus, and Engin. Chem., 4 {1912), No. 11, pp. 841, 842, fig. i).— The 

 method, which simply serves as a control test for the chemical method, is con- 



