RECENT WORK IN AGRICULTURAL SCIENCE. 



CHEMISTRY. 



On the Gunning method for total nitrogen in fertilizers, W. E. 



Garrigues {Jour. Amer. CJiem. Soe., 16 {1894), Ro. 12, pp. 795-79!)).— 

 By following the directions of the official methods' the dunning' nn'tliod 

 invariably gave lower results than the Kjeldahl method. 



"Successful results were finally obtained l)y using the same reagents, both kiiid 

 and quantity [as recouiiuended in the official methods], but varying the mode and 

 order of their addition. . . . Tiie chief fault is in the addition of potassiiun sul- 

 phate at such an early stage in the ])rocess, the larye quantity of dry powder form- 

 ing ail effectual blanket over the sample, that for some time resists the permeation 

 of the viscid acid solution. 



"The best jirocedure was found to be: Adding the salicylic acid mixture directly 

 to the sample in the flask, whicli is then shaken until the liquid has thoroughly 

 wetted the dry organic matter; allow to stand about 15 minutes, and add the 

 thiosulphato with constant shaking. This should be done in 4 or 5 portions, 

 following with a fresh crystal only when the one previously added has completely 

 dissolved. The potassium sulphate is then put in and the whole ag-ain-well agi- 

 tated. Digest as usual." 



Even with this modification there appeared to be a tendency to low 

 results on mixtures containing a considerable proportion of nitrogen 

 in the form of nitrate; and with i)ure nitrate of soda both this method 

 and the modified Kjt'ldahl method gave results considerably too low. 



The determination of phosphoric acid by the moJybdate- 

 magnesia method, 1>. W. Kilcore {Jour. Amer. Chem. Soc, IG {1894), 

 Xo. lL\pp. 79.3-795). — The results of 34 deternunations by 2G chemists 

 of the Association of Official Agricultural Chemists of phosphoric acid 

 in a sample of disodium hydrogen phosphate containing theoretically 

 19.8L'6 Of phosphoric acid are discussed. The- highest result rei)orted 

 was 20.07 per cent; the lowest, 19.74; the average, 20.00. luvestiga- 

 tions are reported which lead to the conclusion that this tendency to 

 high results is due to excess of magnesium in the ammonium magnesia 

 phosi)hate, as Neubauer has pointed out. This may be obviated by 

 dissolving in hydrochloric acid and reprecipitating or by precipitating 

 in the x)resence of citric acid. 



Investigations on the determination of potash by the Lindo- 

 Gladding method, -1. van den Berghe {Lah. A(/r. Frov. Roulers, 



' U. S. Dept. Agr., Div. Chem. Bui. 38, pp. 172, 174. 

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