418 EXPERIMENT STATION RECOED. 



of determining tlie available plant food of soil based on (1) solubility in water, 

 and (2) solubility in water charged with farl>()n dioxid are fully described 

 and advocated. 



On the analysis of nitrate of soda, P. Beck {Ztschr. Analyt. Chem., 4-^ 

 {1906), No. 11, pp. 669-687). — A series of determinations on pure sodium 

 nitrate and on samples of commercial nitrate is reported, which show that the 

 indirect method in common commercial use is inaccurate and should be replaced 

 by direct methods of analysis. 



Scheibler's apparatus for the determination of carbonic acid in carbon- 

 ates; an improved construction and use for accurate analysis, S. H. Collins 

 (Jour. 8oc. Chcm. Indus., 25 {1906), No. 11, pp. olS-o22. fit/s. 3; abs. in BuL 

 Soc. Chim. Paris, 3. ser. {1906), No. 18-19, p. i069.— Studies of the causes 

 of error in the use of this apparatus are reported and a modification which is 

 believed to secure greater accuracy is described in detail. 



Determination of ash in an electrically heated furnace for elementary 

 analysis, II. Seibert {Chem. Ztg., 30 {1906), No. 79, pp. 965, 966).— Referring 

 to a recent article by von Konek (E. S. R., 18, p. 109), the author reports com- 

 parative determinations which show that with proper precautions this method 

 of determining ash does not give higher results than the ordinary methods used. 

 He attributes the higher results obtained by von Konek to occlusion of oxygen 

 by the platinum vessel in which the incineration takes place in the furnace. 



Report of committee on standard methods of water analysis to the labora- 

 tory section of the American Public Health Association {Chicago, 1905, pp. 

 1^1) ■ — This is a reprint in pamphlet form of an article which has already been 

 noted (E. S. R., 17. p. 334). 



The determination of total arsenic acid in London purple, E. G. Mahtn 

 {Jour. Anicr. Chcm. »S'oc., 28 {1906), No. 11, pp. 1598-1601). — The coloring 

 matter is removed from the acid solution by means of chlorin gas. Several 

 slight modifications are made in the methods of the Association of Official Agri- 

 cultural Chemists for reducing the arsenic acid to arsenious acid. 



A direct method for the analysis of milk, E. d'Huart {Inst. Liixemh., Sect. 

 Sci. Nat. [etc.]. Arch. Triinset.. 1906. Nos. 1-2. pp. 125-133, figs. 2). — Instead of 

 sand or other absorbent material the author uses a roll of fine platinum wire 

 gauze sufficient io absorb fi'om 8 to 10 gm. of milk. The gauze containing the 

 milk may be weighed in a covered crucible or in a weighing bottle. After dry- 

 ing to a constant weight and determining the total solids the fat is extracted in 

 a Soxhlet apparatus and the ash subsequently determined on the same sample. 

 Analyses made by this method in comparison with other methods are reported. 



Experiments in relation to milk testing, H. Hoft {Milchw. Zentbl., 2 

 {1906), No. 8, pp. 355-360). — The changes in the total solids of buttermilk upon 

 long keeping were found to be slight. During the first four days the decrease 

 averaged about O.IG per cent and during Q or 7 days 0.33 per cent. After 

 that the reduction was very slight. 



The addition of iinunonia to acid or curdled milk exerted no appreciable in- 

 fluence upon the determination of total solids. Ammonia was added to skim 

 milk, buttermilk, and whole milk, and total solids were determined at intervals 

 for about 3 months. The loss in total solids was small, the greatest amount 

 during a period of 3 weeks being 0.17 per cent. 



On the estimation of proteid in human milk, A. W. Sikes {Jour. Physiol., 

 Si {1906), No. 6. pp. /,81-.i89).—The results and conclusions of the author's 

 investigations are stated as follows: (1) Precipitation of the proteid of human 

 milk by means of hot alcohol is complete; (2) the hot alcohol extracts the non- 

 proteid constituents completely; (3) the addition of a small quantity of citric 

 acid prevents the precipitation of the salts; (4) the jiroteid is weighed directly, 



