614 EXPERIMENT STATION RECORD. 



with the subsequent determination of mono- and diamine nitrogen by the Haiis- 

 mann method as modified by Osborne ( E. S. R., 15, p. 221 ) . 



A colorimetric method for determining phosphoric acid, N. Passeeini 

 (Atti R. Accad. Econ. Agr. Georg. Firenze, 5. ser., 7 {1910), No. 3, pp. 2^9- 

 253). — The method is based on the production of a yellow color by phosphomo- 

 lybdic and gallic acids. Tests of soils with the method are given and compared 

 with the usual molybdate method. 



In regard to the determination of phosphorus in milk, E. Fleurent and 

 L. L6vi iCompt. Bend. Acad. Sci. [Paris], 152 (1911). .Yo. 15, p. 1015).— A 

 polemical discussion in regard to the methods previously described (E. S. R., 

 25, pp. 312, 411). The authors show that the loss in the case of the organic 

 phosphorus must not be ignored, as this is often as high as 21.3 per cent of the 

 total organic phosphorus present in milk. 



Electrolysis of humus solutions. — An improved method for the estima- 

 tion of humus, J. B. Rather (Texas Sta. Bid. 139, pp. 15). — Following a sug- 

 gestion made by Fraps and Hamner in a bulletin previously noted (E. S. R., 24, 

 p. 302), in regard to the possibility of utilizing the electric current for remov- 

 ing suspended clay from soil solutions, the author as a result of his work con- 

 cludes that " electrolysis removed most of the suspended clay from humus 

 solutions and precipitated some of the humus. Electrolysis removed more clay 

 than the Mooers and Hampton method. Electrolysis precipitated more clay 

 than 1 gm. per liter of ammonium chlorid, but less than 2 gm. per liter of the 

 salt. After precipitating the clay with 1 gm. per liter of ammonium chlorid 

 the current used did not complete the precipitation of the clay. The presence 

 of the salts interfere with the precipitation. Nitric nitrogen was formed by the 

 current in the presence of free ammonia. Only a small amount of humus was 

 precipitated by the current in the presence of 1 gm. per liter of ammonium 

 chlorid, much less than by hydrochloric acid. In the absence of ammonium 

 chlorid about a third of the humus was precipitated. All of the humus was 

 not precipitated by hydrochloric acid. Humus and clay are precipitated from a 

 neutral solution by the current. The electrolysis can not be used as a quantita- 

 tive method for removal of clay or of estimation of humus." 



Some further work on other methods of removing clay revealed that " evapo- 

 ration and solution does not remove the clay completely. Clay in humus solu- 

 tions may be precipitated by ammonium carbonate or carbon dioxid, and the 

 precipitant disappears on evaporating and drying the residue. Precipitation of 

 the clay with ammonium carbonate is more nearly complete than by evapora- 

 tion and solution and is a much shorter method." 



A brief bibliography is appended. 



Detection and determination of small quantities of ethyl and methyl 

 alcohol and of formic acid, R. F. Bacon {V. S. Dept. Agr., Bur. Chem. Circ. 

 lit, pp. 8). — ^After discussing the amount of alcohol usually present in decom- 

 posed foods and the limitations of existing methods for determining the amount 

 of alcohol in such foods, the author reports experiments which show that very 

 small quantities of ethyl alcohol may be concentrated from salt solutions to a 

 strength (from 2 to 4 per cent) at which they can be used for determining the 

 amount of alcohol accurately by existing methods. 



The author also studied the Vorisek method (E. S. R., 21. p. 705) for methyl 

 alcohol in regard to its delicacy, and finally decided on the following method: 

 *' To 100 cc. of aqueous methyl alcohol in a 200 cc. distilling flask add from 5 

 to 8 gm. of chromic acid; collect 10 cc. of distillate and test for formaldehyde 

 by the Leach or Hehner methods. If other oxidizable substances, such as acids, 

 sugars, starches, proteids, etc., are present the solution under examination is 

 exactly neutralized with sodium hydroxid and one-third of it is distilled, the 



