432 kxpp:kiment station record. 



Determination of gliadin and g-lutenin in flour by the Fleurent-Manget 

 method, J. S. Chamberlain. — Tliis method was believi'<l to ^ive too lii<,'li, n-fsiilts 

 for gliadin, and, (.'ouseciuently, too low reHult.s for udutciiin. Based upon the results 

 of his study, which were reported in detail, (he aulhor iiave a method for the 

 determination of the proteids of Hour, whieh is in sul)stance ;is follows: 



(1) Moisture is detenuined at 105° ('. in an atmosphere of hydrogen or coal gas. 

 {2) All determinations are made upon air-dry Hour, either standard milled, or 

 capa))le of passing through bolting cloth 90 to 100 meshes to the inch. (8) Four to 

 six grams of the flour is placed in a 150 or 200 cc. ilask and exactly 100 cc. of a 5 per 

 cent solution of potassium sul])hate is introduced. The mixture is shaken frequently 

 for 18 to 24 hours, or jjlaced in a shaker for 6 hours. After settling, 50 cc. is filtered 

 off and the nitrogen determined in this by the Kjeldahl method. The nitrogen 

 imdtiidied by 2 gives the nitrrjgen in the original sample. The nitrogen in the flour 

 multiplied })y 5.68 gives the proteids in the flour soluble in the dilute salt solution. 

 (4) Two to four grams of flour is extracted in a sinular manner with 100 cc. of 70 per 

 cent alcohol, a digestion flask being used. The liquid is filtered off and the residue 

 washed several times into the filter paper and the whole thoroughly washed with 

 alcohol. The' filtrate is acidified with sulphuric acid and evaporated almost to dry- 

 ness when the nitrogen is determined. The nitrogen multiplied by 5.68 gives the 

 proteids soluble in 70 per cent alcohol. (5) Nitrogen is determined in the residue 

 (including filter paper) from the alcohol extraction, which, multiplied by 5.68, gives 

 the proteids insoluble in 70 per cent alcohol. (6) The residue from a second alcohol 

 extraction is extracted with 5 per cent sulphuric acid solution, as described above, 

 and the nitrogen determined. The nitrogen multiplied by 5.08 gives the j)roteids in 

 the residue from alcohol extraction soluble in the dilute salt solution. (7) The dif- 

 ference between the proteids obtained in (6) and (5) is glutenin. The difference 

 between the proteids obtained in (3) and (6) subtracted from the proteids obtained 

 in (4) gives the gliadin. 



POTASH. 



The work on this .subject during" the year was confined to the deter- 

 mination of potash in mixed fertilizers and moisture in potash salts. 

 The reading of the report of the referee was followed l)y a general 

 discussion. No action was taken by the association other than to refer 

 the suggestions and reconnnendations contained in the report to the 

 referee for next year. 



Report of referee, F. B. Carpenter. — .Samples were sent to a large nundjer of 

 chemists, of whom 18 reported results. With one or two excei^tions results by the 

 official method for determining potash were fairly concordant, though in most cases 

 considerably below the theoretical amounts present. A modification of the official 

 method gave higher percentages of potash, but with less uniformity. A modification 

 of the optional method of the association was tried, with the conclusion that it was 

 too troublesome for practical work. 



Numerous exiaeriments were made bj' the referee for the purpose of determining 

 the cause of low results on potash, and i:)f devising some method fur overcoming this 

 difficulty. Neutralization with sodium hydrate instead of ammonium hydrate was 

 tried with promising results. In this modification of the official method a small 

 amount of hydrochloric acid is added to lil)erate any occluded potash in the sub- 

 stance, and sodium hydrate is used instead of ammonium hydrate to prevent any 

 occlusion or absorption of potash in the precipitate. 



No definite conclusions were considered warranted from the amount of work done. 

 Further study of this modification was suggested. The results on moisture by the 



