treatments gave increased yields over the checks, but the effect of the different treatments is not deemed comparable, due to the variability of the soil. Sweet clover outyielded adjacent plats of alfalfa in every case.

Soil acidity as influenced by green manures, J. W. WHITE (Jour. Agr. Research [U. S.], 13 (1918), No. 3, pp. 171-197).-From the results of pot experiments at the Pennsylvania Experiment Station with various leguminous and nonleguminous plants and some common weeds and less desirable grasses applied to a distinctly acid soil both in the fresh and air-dry condition, the conclusion is drawn "that fresh green manures plowed under on this acid silty loam soil reduce its acidity very soon after plowing under, but finally leaves a soil of increased acidity. Also that nitrification goes on in them quite vigorously under suitable moisture, temperature, and aerative conditions and that the green manured soils are rich in nitrates, despite the soil acidity. As to the cause of the increased acidity, beyond showing that it is not largely due to nitrification and indicating that it is in some way associated with the added organic materials or their fermentative residues, the experiments furnished little definite information."

The changes taking place during the storage of farm-yard manure, E. J. RUSSELL and E. H. RICHARDS (Jour. Agr. Sci. [England], 8 (1917), No. 4, pp. 495-563, figs. 10).--The investigations here reported "began in an attempt to account for the loss of nitrogen that occurs during the cultivation of land rich in organic matter or liberally supplied with farmyard manure," as observed, for example, in the Rothamsted plats. As the work progressed, however, it was extended to "deal with the changes in the manure heap independently of their bearing on the changes within the soil." It has included laboratory experiments, investigations on the changes which go on in manure in the stable and in the heap, and studies of the relationship between composition and cropproducing value of manure. A comparative study was also made of changes which take place in the purification of sewage and those occurring in the decomposition of manure.

There was found to be a complete parallel between the decomposition of sewage and manure and a close resemblance between these and the laboratory decomposition of protein. It is concluded "that the decompositions in all cases start in the same way. Under strictly anaerobic conditions they remain the same, but under aerobic conditions further reactions, notably formation of nitrate and loss of nitrogen, set in both in sewage and in manure heaps, which mask the general similarity with the degradation of protein as it has been studied in the laboratory."

Special methods and apparatus used to prove that the loss of nitrogen observed is due to the escape of free nitrogen are described. It was found, however, that under completely anaerobic conditions there was no loss of nitrogen although there was a breaking down of complex nitrogen compounds to am monia, the accumulation of which was greater at 26° C. than at 15°. Neither was there any loss of nitrogen under completely aerobic conditions. Loss of nitrogen due to the escape of free nitrogen occurred only under mixed aerobic and anaerobic conditions which occur when air diffuses in the manure. The experiments showed that nitrification takes place in the manure heap in the presence of air and in the absence of much moisture. It was always observed on the outside layer when drying had occurred, but was never found in the lower depths that had remained moist.

In laboratory experiments under anaerobic conditions it was found that as much as 17 per cent of the dry matter of the manure may be converted into gas. In the heap the proportion is less. The nonnitrogenous constituents, particularly, are affected, as much as one-quarter of the pentosans disappear

ing during the process and other constituents breaking down in like proportion. The gas evolved contained carbon dioxid, marsh gas, and hydrogen. Under aerobic conditions the loss of dry matter was greater and the temperature higher than under anaerobic conditions. The gases involved contained no hydrogen or marsh gas.

The authors conclude that the practical aims in the management of manure, namely, to secure as much dry matter and ammonia and as little loss of nitrogen as possible, are not attained in manure heaps however well put up. "It appears that the heap is at best an imperfect method of storage, but that its defects are lessened by keeping it compact and sheltered, where it will neither be washed by rain nor suffer too much loss on drying, and in particular by avoiding summer storage."

The method of leaving manure under the animals in stalls or covered yards until it is wanted is thought to be the best that can be suggested with our present knowledge. "If the manure has to be stored it should be under anaerobic conditions, and if possible at a temperature of about 26°."

Many analyses of manure from various sources are compiled from which the following averages are deduced:

The historical development of scientific knowledge regarding the decomposition and preservation of manure is reviewed.

Soil fertility work on county experiment farms, C. E. THORNE (Mo. Bul. Ohio Sta., 3 (1918), No. 4, pp. 101-103).—This presents a brief preliminary report of the results of fertilizer tests conducted during 1916 and 1917 along the same general lines as previously noted (E. S. R., 36, p. 829). The conclusion was reached that on the older soils of Ohio acid phosphate could be used to good advantage. High yields were also obtained with potash and nitrogen fertilization, but at present prices the use of these materials is deemed to be unprofitable for the average farmer.

Buying commercial fertilizers, C. E. THORNE (Mo. Bul. Ohio Sta., 3 (1918), No. 5, pp. 139–141).—Tabulated data obtained from the fertilizer experiments noted above are presented to show the total and net value, after deducting the cost of the fertilizer, of the increased yield of crops produced by 100 lbs. of acid phosphate when used alone, when used with muriate of potash, and when used with both muriate of potash and nitrate of soda.

The results are held to indicate that with the present condition of the fertilizer market the purchase of carriers of phosphorus such as acid phosphate, steamed bone meal, and basic slag is alone justified.

A study in farm drainage, C. E. THORNE (Mo. Bul. Ohio Sta., 3 (1918), No. 4. pp. 107-110).—Fertilizer and manurial experiments with corn, soy beans, wheat, and clover grown in rotation on impoverished drained and undrained land in Clermont County, Ohio, are said to indicate that phosphorus, potassium, nitrogen, lime, and drainage are all required for profitable crop production on

these sofls. With manure as the carrier of nitrogen and potassium, on the basis of cost of application only, the cost of the phosphorus and lime and nearly one-half that of the drainage has been recovered at values based on prewar prices of fertilizers and crops, while at values based on estimated present prices the entire outlay was recovered, together with a considerable margin of profit.

The nitrogen problem and the work of the Nitrogen Products Committee (Jour. Soc. Chem. Indus., 36 (1917), No. 22, pp. 1196–1200; Nature [London], 100 (1917), No. 2512, pp. 316-318; Metallurg. and Chem. Engin., 18 (1918), No. 2, pp. 77-81).-This is a preliminary report of the British committee which was organized in June, 1916, to consider the nitrogen problem especially from the standpoint of war needs and to outline plans for increasing the production of nitrogen compounds. It deals especially with plans which are under consideration for increasing the recovery of by-product ammonia and for producing cynamid and utilizing the ammonia oxidation and synthetic-ammonia processes under Government aid and auspices.

The effect of different salts on ammonia formation in soil, G. P. KOCH (Jour. Biol. Chem., 31 (1917), No. 2, pp. 411-413; abs. in Jour. Chem. Soc. [London], 112 (1917), No. 660, I, p. 622).—Investigations at the New Jersey Experiment Stations are reported which show that "utilizing various combinations of MgSO, K2SO1, and Ca (H2PO.) 2.2H2O, and controlling the concentration at two atmospheres, the following effects on ammonia formation from dried blood in soil were obtained: (1) In combinations of the salts where Ca (H2PO、) 2.2H2O was present in only 0.1 of the total concentration a considerable increase in ammonia formation was apparent. (2) When 0.8, 0.9, or all of the total concentration was supplied by Ca (H2PO.) 2.2H2O the ammonia formation was approximately 26 per cent greater than when no salts were added to the soil. (3) MgSO. and K2SO, singly or in combination were toxic where no Ca (H.PO,) 2.2H2O was added in the combination."

Several references to literature bearing on the subject are given.

Nitrate of soda in 1917 (Chem. Trade Jour., 62 (1918), No. 1601, pp. 67, 68). The nitrate situation during and at close of the year is briefly reviewed. It is stated that the production of Chilian nitrate was 2,949,300 tons in 1917 as compared with 2,865,300 tons in 1916. The shipments during 1917 to Europe (including Egypt) amounted to 1,048,000 tons, and to the United States and other countries 1,684,000 tons. It is estimated that the stocks in Chili December 31, 1917, amounted to 882,000 tons. The increased activity in production and export during the year is ascribed to the high price and great demand from munitions factories. The price of the nitrate was almost prohibitive of its use as fertilizer.

Bibliography on the extraction of potash from complex mineral silicates, E. C. BUCK (Metallurg. and Chem. Engin., 18 (1918), Nos. 1, pp. 33-37; 2, pp. 90-95). This bibliography includes a full list of references to patents and periodical literature relating especially to the sintering of phosphatic rocks with feldspars, but also to other methods and processes applicable to feldspars, leucite, and glauconite (greensand marl).

A neglected chemical reaction and an available source of potash, E. A. ASHCROFT (Chem. Trade Jour., 61 (1917), No. 1596, pp. 529–531; Sci. Amer. Sup. 85 (1918), No. 2216, p. 390).—This article, which is an abstract of a paper discussed at a meeting of the Institution of Mining and Metallurgy in London, calls attention to the fact first discovered by Bassett that, "if any common variety of orthoclase or microcline feldspar be dry crushed to 100 mesh in an iron mill and mixed with its own weight of pure dry common salt, and then

heated to from 900 to 1,000° C. for two hours out of contact with air or moisture or furnace gases carrying such air or moisture, . . . the sodium base of the salt displaces the potassium base of the feldspar strictly according to the equation:

2NaCl+K2OAl2O: (SiO2).=Na2OAl2O: (SiO2).+2KCl.

"If the temperature has not exceeded 1,000° C., and if moisture and air have been carefully excluded, the product will be found to consist of finely divided insoluble sodium feldspar (albite) and a mixture of quite neutral and freely soluble sodium and potassium chlorids. These chlorids may be readily lixiviated in water, and are easily separated from each other by fractional crystallization. The extraction of potash obtainable by this means from a sample of feldspar carrying upward of 10 per cent K2O will be in the neighborhood of 85 per cent under the conditions above stated. There is no loss by volatilization, and the weights of residue and salt will be found to correspond with the equation."

The practical application of this reaction in the preparation of potash salts from feldspar is discussed and experiments with the process are reported. An emergency process suited to present conditions is described. The author holds that "all consideration of by-products in such schemes should be a secondary thought and should not form an essential part of the scheme."

Sources of potash, T. E. THORPE (Nature [London], 100 (1918), No. 2514, pp. 344-347; Sci. Amer. Sup., 85 (1918), No. 2198, p. 103).-This article deals especially with the Bassett-Ashcroft process of preparing potassium chlorid from feldspars (noted above), but also briefly describes the Stassfurt. Alsatian, Spanish, and Abyssinian deposits of potash salts. Attention is called to the fact that "conditions such as probably have produced the Stassfurt deposits are still at work and may be observed in several parts of the world operating over large areas, as, for example, in the Adji-Daria Bay, in the east of the Caspian Sea. . . . None of these areas has been investigated with such care as that of the North German plain, but the general conditions which have led to their production are seen to be similar, although local circumstances, especially the extent to which they were subjected to an intermittent influx of sea water, have modified the nature, relative amounts, and distribution of their various saline constituents."

Italian leucitic lavas as a source of potash, H. S. WASHINGTON (Metallurg. and Chem. Engin., 18 (1918), No. 2, pp. 65–71).—In this article "attention is called, as a future possible source of potash, to the leucitic lavas of seven volcanoes along the west coast of Italy from Bolsena to Vesuvius. The rock types are characterized and the several volcanoes described succinctly. The volumes of the volcanoes, the tonnage of the lavas, the percentage of potash, and the total (minimum) amount of potash at each are calculated. It is shown that the leucitic lavas of these volcanoes, with an average potash content of about 9 per cent, contain at least 8,786,200,000 metric tons of K2O, making them the greatest accumulation of highly potash-rich silicate rocks known. Methods of extraction of the potash are not discussed."

Recovery of potash from greensand, H. W. CHARLTON (Jour. Indus, and Engin. Chem., 10 (1918), No. 1, pp. 6-8; Amer. Jour. Sci., 4. ser., 45 (1918), No. 266, p. 142).-This deals with a process which was originally developed for the treatment of feldspar for the extraction of potash but which has been found to apply more advantageously to greensand or glauconite.

"The process consists in heating the finely ground mineral under pressure with water and lime in autoclaves. Steam at a pressure of about 225 lbs.

is led directly into the digester and this is maintained for a period of two to four hours. Although glauconite contains less potash than feldspar, it has been found that it is decomposed more readily than the latter, and that it yields potassium hydroxid that is nearly pure. It is proposed to utilize the waste material obtained by filtration from the potash solution for making bricks, tiles, and similar articles, as it has been found that when mixed with sand, pressed, and steam hardened it makes durable products."

Sources of potash, H. MAXWELL (Nature [London], 100 (1918), No. 2516, p. 384).-Discussing the value of bracken fern as a source of potash, analyses are reported which show that the sample of air-dried fern examined contained 4.82 per cent of ash, of which 41.5 per cent was potash; that is, the dried fern itself contained about 2 per cent of potash. The ash contained in addition small quantities of phosphoric acid.

Kelp industry in British Columbia (Jour. Soc. Chem. Indus., 36 (1917), No. 13, p. 710; abs. in Chem. Abs., 11 (1917), No. 23, p. 3368).—This is a brief note on the operations of a plant established at Sydney, B. C., in 1915, for the production of potash and algin. The plant is now utilizing from 30 to 40 tons of raw kelp daily in the manufacture of fertilizer, the product being a fine, dry, but heavy powder. It is believed that the manufacture of potash and iodin, without the production of by-products, would not prove profitable in normal times. It is estimated that the kelp beds on the coast of British Columbia contain sufficient material to supply not only the local requirements for potash but some for export.

The value of phosphates on Indiana soils, A. T. WIANCKO and S. C. JONES (Indiana Sta. Bul. 210 (1918), pp. 16, figs. 4).-Field tests with different phosphates conducted during the past 12 years on 5 experimental farms representing different soil types found in the State have led to the following conclusions:

Acid phosphate has given the best results, with basic slag and steamed bone meal next in order of profitableness. Rock phosphate gave good results in certain cases, but showed the least profit. In immediate returns on the first and second crops after application, acid phosphate has yielded crop increases of from 3 to 25 times as much as those obtained from rock phosphate. Neither acid nor any other phosphate used increased soil acidity or the need for liming, although Indiana soils needing phosphorus are deemed generally to be in need of lime also.

Based on the results obtained, recommendations for soil improvement are briefly outlined, and include a systematic rotation of crops, liming, drainage, manuring, and the application of from 150 to 200 lbs. per acre of acid phosphate or some other readily available phosphate to each grain crop in the rotation.

Indiana soils need phosphates, A. T. WIANCKO and S. C. JONES (Indiana Sta. Circ. 79 (1918), pp. 8, figs. 3). This presents in a condensed and popular form the results of the work noted above.

The relative value of limestone of different degrees of fineness for soil improvement, J. W. WHITE (Pennsylvania Sta. Bul. 149 (1917), pp. 3–24, figs. 11). This bulletin reports the results of both laboratory and greenhouse experiments to determine the relative value for soil improvement of high calcium and magnesium limestone ground to pass 100, 60, 20, and 8 mesh screens, respectively, the finer material in each case being excluded, except from the 100-mesh grade, as compared with equivalent amounts of the burned products. The studies were made during the period 1915 to 1917, inclusive, and embraced observations upon the solubility of the different grades in pure and carbonated water; upon their relative value in correcting soil acidity and in the formation