206 EXPERIMENT STATION EECOKD. [Vol. 3S 



nitric acid. Tliat left in tlie residue was tlie result of an incomplete extraction 

 by the acids employed." In one soil the Hilgard method extracted as much acid- 

 soluble phosphoric acid as did the Fischer method, but in another .sample con- 

 siderably less. 



" Washington's method, when applied to soils and modified to the extent of 

 igniting the residue to dull redness after the final evaporation with nitric acid, 

 failed to recover the whole of the phosphoric acid present. The residues upon 

 being fused with sodium carbonate yielded the missing amount, thus showing 

 that the low percentages found by this method are not due to volatilization 

 during ignition but to incompleteness of extraction by nitric acid. 



" Robinson's modification of Washington's method extracted only from 50 to 

 65 per cent of the total phosphoric acid, the remainder being found partly in 

 the residue and partly in the filtrate from the yellow precipitate. With soils 

 high in organic matter the magnesium pyrophosphate obtained by this modi- 

 fication of the method carried a considerable amount of magnesium oxid, which 

 was derived from precipitated organic compounds. A temperature so low that 

 no glowing was produced failed to oxidize the organic matter completely. 

 Samples analyzed by this modification of Washington's method, with the ex- 

 ception that after the first evaporation with nitric acid they were ignited to 

 very dull redness, behaved similarly, although no phosphoric acid was found 

 in the filtrate from the yellow precipitate." The incomplete extraction of the 

 phosphorus from soils by Washington's method was found to be due to over- 

 heating of the residue, causing the formation of difficultly soluble phosphates 

 or iron and aluminum. 



The amount of titanium oxid found in soils is considered to be too low to 

 interfei-e with the precipitation of the phosphorus. 



The data are submitted in tabular form and discussed. 



Rapid determination of bran contained in flour and bread, R. Legendre 

 {Ann. Falsif., 10 (Wit), No. 105-1G6, pp. 293-296, fig. i).— The following pro- 

 cedure is described : 



After determining the moisture in a 2-gm. sample of flour or a 3-gm. sample 

 of bread crumbs, the material is treat^l in a test tube or other suitable con- 

 tainer with 10 cc. of water and 10 cc. phosphoric acid (specific gravity 1.38) 

 and the mixture heated in an autoclave for one hour at 120° C. After cooling, 

 the contents of the tube are placed on a small, previously moistened silk sieve 

 (number 100 or 120) and carefully washed with a small stream of water until 

 the washings are clear. The bran on the sieve is returned to the tube, water 

 added, and the mixture again returned to the sieve and washed. After being 

 thoroughly washed it is collected, dried, and weighed. Where the method is 

 used for spaghetti and similar products the time of heating should be prolonged. 



The procedure is indicated as being sufficiently accurate for the detection of 

 adulteration of either flour or bread. 



Tentative standard methods for the sampling and analysis of commercial 

 fats and oils, other than those of the coconut, butter, and linseed groups 

 (Jour. Indus, and Engin. Chem., 9 (1917), No. 11, pp. 1066-1070, fig. i).— The 

 methods of sampling and analysis reported have been adopted by the committee 

 on the analysis of commercial fats and oils of the Division of Industrial 

 Chemists and Chemical Engineers of the American Chemical Society as tenta- 

 tive standards for the use of the trade pending their official adoption by the 

 society. 



Occurrence of manganese in insect flowers and insect flower stems, C. C, 

 McDoNNEix and R. C. Roark (U. S. Dept. Agr., Jour. Agr. Research, 11 (1917), 

 No. S, pp. 77-82). — Tabular data relative to the manganese content of stems 



