DETERMINATION.

Place 500 cc. of the sample in a beaker or casserole, add 30 cc. excess of N/2 sulphuric acid solution. Boil the solution carefully until free of sulphid (about 20 minutes). Add about 300 cc. of distilled water and 8 cc. of 5 N sodium carbonate solution to a distillation flask connected as described in the official method1, and distil until free from ammonia. Cool and add the cooled sample which has been freed from sulphid. Proceed with the distillation, addition of alkaline permanganate solution, etc., as described in the official method.

(6) That the methods on water be extended to cover the examination of allied products, such as brine and salt.

(7) That continued study be given to the determination of iodin and bromin and the heavy metals and to the use of equivalents in studying the character of waters.

REPORT ON SOILS.

By C. B. LIPMAN2 (University of California, Berkeley, Calif.),
Referee on Soils.

The report covers work undertaken two years ago on "The Total Phosphorus Determination". Of those who had promised to collaborate, only two sent in reports; namely, H. C. McLean (Agricultural Experiment Station, New Brunswick, N. J.) and L. A. Steinkoenig (Bureau of Soils, Washington, D. C.). The two former official methods for total phosphorus determination, namely, the magnesium nitrate method and the sodium peroxid method which the association adopted two years ago as tentative1, were studied. Two California soils, the Davis soil and the Oakley soil, were employed. The results obtained by the two collaborators are given in the following table:

Determination of total phosphorus-results as phosphorus of water-free soil.

In Steinkoenig's case, two additional methods to those for which directions were issued were tried on the same samples. On studying these results, your referee finds that determinations made in quadruplicate by McLean in every case with each method and with each soil agreed well among themselves. The duplicate results obtained by Steinkoenig also agree well among themselves. The agreement between the results of the two collaborators is not so good as could be desired. Mc Lean's results show that there is little choice between the two methods, though there is a possibility that the magnesium nitrate method is a little more thorough. This is just a possibility, however, and is offset by a certain difficulty in dehydration which was experienced by McLean with the method. With the Oakley soil even this slight difference between the two methods seems to have disappeared. In the case of McLean's results, the magnesium nitrate method is superior for the Oakley soil and the sodium peroxid method superior for the Davis soil. On the whole, your referee can not see sufficient difference between the figures submitted to justify drawing any other conclusion than that both methods so far adopted remain as they are for at least another year.

RECOMMENDATION.

It is recommended that the study of the determination of total phosphorus in soil be continued with a larger number of soils and that an attempt be made to secure more collaborators.

There was no associate referee on the nitrogenous compounds of soils and no report on this subject was presented.

REPORT ON THE LIME ABSORPTION COEFFICIENT
OF SOILS.

By W. H. MACINTIRE (Agricultural Experiment Station, Knoxville,
Tenn.), Associate Referee.

During the past two years abnormal conditions have seriously handicapped any extensive work along collaborative lines. The unusual demand placed upon station facilities has necessitated the suspension of all work not of primary importance. For this reason, those who offered collaborative assistance have been unable to fulfill the proffer made.

However, following the more exhaustive previous report1 made upon the results secured through selective collaboration upon representative procedures, and the adoption of the recommendation that the Jones

1 J. Assoc. Official Agr. Chemists, 1920, 4: 108.

calcium acetate method be further studied, the writer has given, with some assistance, special attention to the fundamentals of the method and the technic of the procedure. Exchange of opinions as to the merits of the method has brought out the fact that the Jones method is well adapted to its intended use. Without in any sense being derogatory to other procedures, which may be well adapted to certain conditions, it seems to be the consensus of opinion that the Jones calcium acetate method fills the need of an absorption method to replace the abandoned sodium nitrate procedure.

Results from the Vermont and Virginia Agricultural Experiment Stations indicate a close parallel between results secured by the Jones procedure and those obtained by the method of Veitch. While it is true that the principles underlying the Veitch procedure are fundamentally correct from a physical chemical viewpoint, the method is not so well adapted to rapid laboratory manipulation as is the Jones procedure.

Results secured during three years, and in particular the slight variations reported in the factor, found applicable to different soils, together with the factor utilized in the Jones procedure, tend to justify the conclusion that the method, after certain slight editorial changes and modifications in technic are introduced, may well be adopted tentatively as a laboratory procedure for the purpose of determining the lime absorption coefficient of soils. These slight modifications have been presented to the originator of the procedure, C. H. Jones, Agricultural Experiment Station, Burlington, Vt., and have received his sanction.

JONES METHOD FOR DETERMINING LIME ABSORPTION COEFFICIENT. Take 5.6 grams of soil, add 0.5 gram of calcium acetate (tested reagent), place in a 3-inch mortar and mix with a pestle. Add sufficient water (room temperature) to make a fairly stiff paste. Pestle for 20 seconds, add 30 cc. of water and continue the mixing for 30 seconds. Wash into a 200 cc. flask and keep the bulk down to about 160 cc. Let stand with occasional shaking for 15 minutes. Make up to a bulk of 200 cc., mix and filter through a dry filter. Discard the first 10-15 cc. which may be cloudy. For rapidity and efficiency the Büchner funnel is recommended. Titrate 100 cc. of the clear filtrate, using phenolphthalein as an indicator, with N/10 sodium hydroxid. This reading multiplied by 2 gives the number of cc. of N/10 alkali required to neutralize the acetic acid in 200 cc. of the solution. This figure times the factor 1.8 times 1000 indicates the pounds of lime (CaO) required per 2,000,000 pounds of soil.

RECOMMENDATION.

If further study of the tentative method be thought advisable, it is recommended that such a study be made upon the factor of soil type in its influence upon variation in the factor to be applied.

REPORT ON INORGANIC PLANT CONSTITUENTS.

By J. H. MITCHELL1 (Clemson Agricultural College, Clemson College,

S. C.), Referee.

I wish to review, briefly, the work that has been done on this subject during the past five years. In 1915 A. J. Patten2 showed that the present molybdate method for the determination of iron, aluminium, phosphorus, calcium and magnesium was not accurate when used on material containing a large amount of phosphorus and low percentage of calcium and magnesium. This condition exists in such material as the ash from cereals, legumes and many seeds. No collaborative work was done in 1915, but the referee did some work on a method for calcium and magnesium. The following recommendation was made: "That suitable methods be devised for the determination of iron, aluminium, calcium and magnesium in the ash from seeds".

In 1916 Patten3 presented a method for determining calcium and magnesium in the presence of phosphoric acid, iron and aluminium; also a method for determining manganese colorimetrically. No collaborative work was done, but it was recommended that the methods as outlined for calcium, magnesium and manganese be further studied on solutions approximating the composition of the ash of cereals, seeds, etc.

In 1917 and 1918 no recommendations were made, so the present referee decided to continue the study of the methods for the determination of calcium, magnesium and manganese in the presence of a large amount of phosphorus, as recommended and approved in 1916.

A synthetic ash solution was made of approximately the compostion of the ash of certain seeds, cereals and legumes. It contained iron, aluminium, phosphorus, calcium, magnesium and manganese in the following proportions:

A sample of this solution was sent to eight chemists. The following table shows the results obtained:

1 Presented by W. L. Latshaw.

2 J. Assoc. Official Agr. Chemists, 1917, 3: 153.

Ibid., 1920, 3: 329.

These results vary somewhat, yet taken as a whole they are very good, especially those for calcium. The results on magnesium show a little wider variation and are, on the average, higher than the theory. Owing to a difficulty in obtaining potassium periodate, only a few results were obtained for manganese. These, however, were very good.

The following is an outline of the methods sent to the different chemists:

CALCIUM.

Remove 25 cc. of the solution, representing 0.5 gram of ash, and dilute to 200 cc., add a few drops of alizarine or methyl orange and make slightly ammoniacal. Add very dilute hydrochloric acid (1 to 10) until the solution is just faintly acid, followed by 10 cc. of N/2 hydrochloric acid and 10 cc. of 2.5% oxalic acid. Boil the solution and add, with constant stirring, 15 cc. of a saturated solution of ammonium oxalate, and continue to heat until the precipitate becomes granular. Cool and add, with constant stirring, 8 cc. of 20% sodium acetate solution, and allow to stand 12 hours. Filter, and wash with hot water until free from chlorids. Dissolve the precipitate in hot, dilute sulphuric acid and titrate with N/10 potassium permanganate solution. In dissolving the precipitate it is best to first wash it off the paper into a beaker, and dissolve the portion remaining on the paper with hot dilute sulphuric acid (1 cc. N/10 KMnO4 0.0028 gram CaO).

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