2/6 Report of the Chemical Department of the 



ists:^^^ 5 grams of material was well mixed in a platinum dish with 

 2-4 cc. of a solution of magnesium nitrate and incinerated at a low 

 heat. In most cases a perfectly white ash was obtained. This 

 residue was dissolved in dilute hydrochloric acid, and made up to 

 200 cc, an aliquot being taken for the estimation of total 

 phosphorus. 



Neumann nictliod. — This is the method described by Neumann ^-^ 

 and already used by Sherman : ^^^ 5 grams of material was placed 

 in a Kjeldahl flask, 10-15 cc. concentrated sulphuric acid was 

 added and the mixture was heated over a low flame until well 

 charred. When partly cooled 5-10 grams of ammonium nitrate 

 was added and the digestion continued. Further additions of am- 

 monium nitrate were made from time to time to entirely oxidize 

 and decolorize the mixture. On cooling, the residue was rinsed 

 into a 200 cc. flask, diluted to the mark and an alicjuot was taken 

 for the determination of total phosphorus by the molybdate- 

 magnesia method. The large amount of ammonium sulphate 

 formed on neutralizing with ammonia seems to impede the pre- 

 cipitation of ammonium phospho-molybdate and only when a 

 generous excess of ammonium molybdate was added — 150 cc. — 

 did we get a rapid separation of the " yellow " precipitate. 



Table I. — Comparison of Methods for the Determination of 



Phosphorus. 



Substance. 



Corn 



Oats 



Wheat bran .. 



Malt sprouts 



Brewers' grains., 

 Distillers' grains. 



Linseed meal 



Oat straw , 



Alfalfa 



Meat meal. . 



Liver meal...... 



Dried blood 



Cow feces...... , 



Percentage of phosphorus found in air-dry 

 material. 



(1) U. S. Dept. Agr., Bur. Chem.. Bui. 46, rev, ed. 



]^) DuBois-Reymomr s Archiv. (Physiol. Abth.), 1897, pp. 552-553. 



{^)Jonr. Amer. Chem. Soc, 24: iioo (1902). 



