mental basis for all other agricultural investigations. The reports describe the origin, mode of formation, and physiographic features of the soils, and discuss their physical and chemical characteristics, fertility factors and manurial requirements, their adaptation to crops and to rotation, and the methods of management required to achieve the best results in cultivation.

These reports are now extensively used by the following interests, and are being more used and more fully appreciated with extension and better understanding of the work:

EXPERIMENT STATIONS, UNIVERSITIES, AGRICULTURAL SCHOOLS, AND STATE OFFICIALS.

The soil surveys, giving as they do the orderly arrangement and classification of the soils of the State, are of value to the experiment stations in giving a soil-type basis for investigations of the fertilizer requirement, crop rotation, crop adaptation, plant breeding, plant diseases, and soil management of particular farms or of large areas in any particular State, for the establishment of substations on important soil types, and for farm demonstration work.

They are of value to the State geological surveys, as the mapping of the material (the soil) assists them in their work of mapping according to age, especially where rock exposures or fossils are not freely disclosed. The soil is one of the principal economic expressions of the geological work, the soil material being the resultant of geological processes acting on geological material. Furthermore, soil characteristics are frequently very valuable evidence of geological processes or conditions of great importance for other geoeconomic problems.

The soil surveys are of value to the State departments of agriculture, in that they enable a more intelligent collection of statistical data relating to the present status of farming interests and to the possibility of future development of agriculture along safe and rational lines.

The soil surveys are of value to the university and agricultural school as a basis of instruction in agriculture, in commercial geography, in political and social economy, and in geology, physics, and agricultural chemistry.

The maps are of value and are being used by State officials in colonization work and in some States as a basis for the fixation of land values for just taxation.

GOVERNMENT DEPARTMENTS AND FEDERAL OFFICIALS.

The soil surveys are of value to the War Department in arranging for camp sites and for military maneuvers.

To the Reclamation Service in construction work and in the use and disposal of the lands of the irrigation projects when completed.

To the Land Office for the determination of the agricultural value. of lands.

To the Forest Service for the same purpose, and for determining what lands to devote to permanent forest use and the varieties of trees adapted to the soil types.

To the Bureau of Animal Industry in tick eradication and dairy work.

To the Bureau of Plant Industry in plant breeding, disease, farm management, and demonstration work.

To the Post Office Department in the location of rural delivery routes.

To the Department of Justice and the courts in cases arising out of damage suits and in mineral-land cases.

BOARDS OF TRADE, MUNICIPAL AUTHORITIES, AND BUSINESS ORGANIZATIONS.

Such local organizations frequently ask for and use the results of the soil surveys for the encouragement of more profitable agricultural development of the surrounding territory and as a means of attracting a desirable class of farmers and farm labor for the upbuilding of agriculture and the betterment of trade conditions.

RAILWAYS, REAL-ESTATE COMPANIES, AND COLONIZATION ORGANIZATIONS.

The soil surveys are of value to railroads in giving reliable and impartial information with regard to the soils and agricultural possibilities of the territory through which the lines run; in showing them lines of agricultural development which they can foster for the fuller development of the country and the increase of their own

revenues.

The surveys are of value to real estate companies in that they give an impartial and authoritative basis for dealing in lands, which can be obtained in no other way. They tend to steady business and prevent unjust and unlawful speculation.

The surveys are of value to colonization organizations, as well as to the railways, in furnishing exact and reliable bases for the intelligent settlement of communities, particularly in placing the large number of farmers reaching our shores from foreign countries through the Immigration Service. These people are particularly in need of reliable information regarding localities where they can settle and take up agricultural industries with which they are reasonably familiar. The farmers of southern Italy, of northern Italy, of France, Germany, Sweden, Holland, Ireland, and other countries have certain traits and characteristics and have acquired habits and adaptabilities which can be successfully applied to certain soil types and certain conditions, and are likely to be unsuccessful unless these conditions are approximately fulfilled.

BANKS, INSURANCE COMPANIES, ATTORNEYS, AND OTHERS INTERESTED IN LOCAL VALUES.

The soil surveys are of value to financial institutions in that they give reliable and impartial information as to the soil and agricultural opportunities of the areas surveyed. Several real estate companies have reported that purchasers invariably require to know the location. on the soil map of the farms which are offered to them for sale. In the same way financial institutions free to loan money on mortgages

and for agricultural enterprises use the reports of the soil survey as they would use the reports of mining experts as to the value of mining properties for which a loan is desired. In other words, the report of the soil survey has a commercial value in that the owner of the land can more readily raise money on mortgages and a financial institution can more safely loan money on mortgages on the basis of the soil survey than on any other data that can be obtained. GRANGES, PRACTICAL AGRICULTURISTS, AND AGRICULTURAL FIRMS.

The soil surveys are of value to the farmer in many ways. They give him first of all an accurate and impartial description of his soils, thus enabling a direct comparison with the soils of other localities. They show what may be expected of the soils when intelligently cultivated, the proper crops to plant, and the possibilities of adopting on their farms crops and methods of culture that have been successfully inaugurated in other localities with similar soils. They give him an advantage in dealing with other individuals and with real estate companies in the sale of his land. They give him and his sons the advantage of more specific training in the agricultural schools and universities. They give him certain advantages of knowledge in purchasing lands from real estate agents. They give him a basis for consideration from the railroads and business organizations, which consideration is often required in the building up of new agricultural enterprises. They give him an advantage in dealing with financial institutions in securing loans, and finally they aid him in securing more intelligent and more competent labor. The surveys are also invaluable for anyone selecting a farm in a locality with which he is not personally acquainted.

The soil survey is of value to agricultural firms in that it gives them a basis for the supply of the proper kind of implements, seeds, and fertilizers.

PHYSICAL AND CHEMICAL LABORATORY INVESTIGATIONS.

As is usual, the laboratories have made a large number of physical, chemical, and mineralogical analyses. This work has been done not only for other divisions of the Bureau of Soils, but also for other bureaus and departments, and, under certain restrictions, for the public at large. It has included the analysis of muck soils in connection with the reclamation of marsh lands in the East and the analysis of local soils and waters in connection with drainage, irrigation, and reclamation in the West. Special attention has been given to mineralogical and physical methods of soil analysis. The mineralogical methods developed in this division have proven so valuable that a bulletin is being prepared describing the application of these methods to soil investigation. A mineralogical examination has been made and the physical characteristics determined of a number of important soil types of this country. A similar work has been done in connection with a number of dune sands from the West, with the object of explaining the formation of certain wind-borne sediments of the plains.

Special attention has been given to work on the differences that exist between normal soils or soils that, subject to the ordinary

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methods of analysis, appear to be similar in every way, but which differ markedly in their normal relations to crops and to crop adaptation. When subjected to a careful mineralogical examination such soils frequently show marked differences in mineral composition. Important results along this line have been obtained in a work involving the complete analyses of widely distributed and important soil types. These were selected to represent soils of various origins in respect to the materials from which they were formed and with respect to the processes of formation. Special attention has also been given to substances present in small quantity, such as are always ignored in soil analyses, a consideration of which may show differences in composition of soils hitherto assumed to be chemically alike. The vegetable life which a soil supports is known to contain a large number of elements that are ordinarily not considered essential to its growth, and since it has been found that a small amount of arsenic is necessary for the proper functioning of certain animal tissues, it seems probable that other elements besides the few which have heretofore been assumed to be the only essential ones, although present in very small quantities in the soil or in the plant, may be equally essential to plants or regulate in some essential way the functioning of the soil. The presence or absence of these rarer elements in the soil and their proper correlation to plant growth are, therefore, of great importance. This work has no parallel in all previous analyses of soils.

Experiments have been carried on to determine the effect of soluble salts on the physical properties of soils. It has been shown that the effects of such salts in soils on the penetrability, volume change, moisture, and vapor pressure of the soil solution are measurable and larger than generally supposed. A bulletin has been prepared indicating these results. In view of the lack of precise treatment of the surface-action factors in modern literature on soils, agricultural chemistry, bacteriology, biology, and cognate sciences, a thorough study of the fundamental, mathematical treatises extant was undertaken with the object of attempting a condensed correlation of these factors.

The work on flocculation and sedimentation has been continued. A detailed study of tillage has been made with the object of preparing for publication a bulletin on tillage methods. A very large number of mechanical analyses carried out in this laboratory has made it possible to get data for a bulletin discussing the distribution. of silt and clay particles between soils and subsoils. It has been shown that in humid regions the subsoils are, in a large majority of cases, heavier than the soils, and the reverse is true in the arid regions. This is due to the fact that in the humid regions the run-off carries the finer particles with it and the cut-off also carries them down.

Previous studies on the absorption of nutrient salts by soils and soil materials have been continued. It has been found that phosphates which had been absorbed by soils and other finely divided minerals, such as quartz, can be released from the absorbed state and obtained in solution by the addition of various dissolved salts, such as sodium nitrate, potassium nitrate, potassium chloride, potassium carbonate, etc. The fact that phosphate held in a condition not easily

leached by water may be still further extracted when other salts are added in solution in water has an important bearing upon the theory and practice of plant growth and soil treatment in that the effects produced by the addition of, for example, a nitrate may not be due only to nitrate itself, a portion of the beneficial effect being due to liberated phosphate.

In connection with the work on fertilizers and fertilizer materials which the division has undertaken, a thorough study has been made of the phosphate deposits of Tennessee, Arkansas, and Kentucky. The values of the different types of phosphate rock found in the same and in different places have been properly correlated by a large number of analyses. The methods of mining, the extent of the operations, the cost of production, and the future outlook for the industry have been carefully investigated and described. The information thus acquired, combined with that already published by the bureau, constitutes a very valuable addition to our knowledge concerning the phosphate deposits of this country. A crystallographic and photographic study of the minerals spodiosite, brushite, monetite, and artificial calcium phosphate compounds has been undertaken, with the object of throwing light on the natural formation of these minerals. An investigation of the Otero Basin of New Mexico has been made for possible deposits of potassium salts, and a large amount of information acquired which will be of use in extending the work to other parts of the country.

In collaboration with the United States Geological Survey, an examination has been made of 17 salt-producing plants distributed through central New York, Michigan, and Pennsylvania, for the purpose of obtaining information concerning the source of brines. and lake salt, their composition with special reference to their potash content, and their treatment. All information thus obtained bears on the problem of the occurrence of potash in brines and lake salts and its possible extraction therefrom. With the same object in view, a study is being made of the separation of potassium chlorides and sulphates of calcium, magnesium, and sodium, the solubility of sodium and potassium sulphate in the presence of each other, and the separation of potassium and sodium salts by other methods.

Work is being done on possible methods of separating potash from feldspar and other silicates, and an investigation is also being made concerning the chemical fixation of atmospheric nitrogen, both from a scientific and technical standpoint. This work constitutes an economic examination of the available sources of nitrogen for agricultural purposes and is cognate with the work on phosphates and potash. A survey of the occurrence of and distribution of potashbearing algæ on the American coast has been started with particular reference to their utilization as a source of potash supply. This work on fertilizers and fertilizer materials has very large economic possibilities to the American people.

SOIL FERTILITY INVESTIGATIONS.

There have appeared a number of reports from this laboratory dealing with the nature and properties of soil organic matter or humus, and in connection with these problems some far-reaching discoveries have been made in soil investigations. During the past year