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CHARLES KIRCHHOFF, Chairman. ALBERT SAUVEUR, Vice-Chairman. HERBERT M. BOYLSTON, Secretary, Abbot Bldg., Harvard Sq., Cambridge, Mass. John Birkinbine, J. E. Johnson, Jr., J. S. Unger, William H. Blauvelt, William Kelly, Felix A. Vogel, James Gayley, Richard Moldenke, Leonard Waldo, Henry D. Hibbard, Joseph W. Richards, William R. Walker, Henry M. Howe, C. F. W. Rys, William R. Webster, Robert W. Hunt, E. Gybbon Spilsbury, Frederick W. Wood. A. A. Stevenson, J. S. Unger and C. F. W. Rys have accepted membership on the Iron and Steel Committee. The Program Committee has held two meetings- in New York and has perfected the preliminary plans for the October meeting. The Committee will meet again in September. The following provisional program has been laid out by the Program Committee, but is subject to later additions and changes :

Jan 9, 1913

By John F. Abel

At the spring meeting of the Open Pit Division of AIME's Arizona Section, I was asked a question which indicates the acceleration of technical advancement. The question was: "How does an engineer at a properly keep abreast of what is new?" The fact that some 200 Arizona AIME members were at the meeting is a testimonial to the desire of these men to do just that- keep abreast. There is a great deal of talk in academic circles about the built-in obsolescence of an engineering or scientific education, too. About 100 commencement speakers every spring are sure to admonish the graduates that education is a continuing thing. Mining engineers are a small fraternity. We keep informed by talking to one another. Talking shop is valuable but there is no substitute for reading.

Jan 1, 1970

By Michael Perch, Charles C. Russell

Nearly 7 5 per cent of the total coke production in the United States in 1940 was consumed in blast furnaces. In 1939 the percentage was 69.9, and in 1938 it was 61.3. To produce a net ton of pig iron 1757 lb. of coke was required in 1940 and 1760 lb. in 1939. These figures indicate how dependent the production of pig iron is upon the production of coke. The rate of iron production is in some measure influenced by the physical and chemical characteristics of the coke. Blast-furnace operators believe that the physical properties of coke profoundly influence the operation of the furnace. Although it is true that coke of a wide variety of physical properties is used in American blast furnaces, the periodic fluctuation of these properties is one of the causes of irregularity of blast-furnace operation. The purpose of this paper is to present a broad picture of the physical properties of by-product coke that are generally considered to be important by coke-oven and blast-furnace operators. Effects of the kind of coal used, the preparation of the coal, the rate of coking, and other factors will be considered. Of all these variables, the kind of coal used is by far the most important. In this discussion use will be made of the method of coal classification by rank1 standardized by the American Society for Testing Materials. Although this method of classification has been an American standard for several years, it has not been given the attention it deserves, especially in connection with the selection of coal for production of coke. Despite the fact that many producers of blast-furnace coke are limited to some particular source or sources of coal, a good understanding of the principles involved in setting up the standard method of classification may lead to a better appreciation of the causes of changes in coke characteristics. Furthermore, where it is necessary to select new coals as a substitute for the original supply, this method of classification can be of great assistance. The data presented have been gathered from many sources, but no attempt has been made to cover the vast literature. Instead, some of the more important data have been selected to show how coals and their carbonization affect some of the physical properties of coke. It must be emphasized that generalizations concerning the behavior of coking coals are presented and that individual coals may vary widely from the specific behavior depicted. Nevertheless, it is believed that the data illustrate certain typical behaviors. Neither was it possible to cover completely all the factors involved; for example, the macroscopic constituents of coal are believed to have important effects on the physical properties of coke, but since there is little information available for such study, and since vitrain, clarain, and durain are neither

Jan 1, 1943

By Michael Perch, Charles C. Russell

Nearly 7 5 per cent of the total coke production in the United States in 1940 was consumed in blast furnaces. In 1939 the percentage was 69.9, and in 1938 it was 61.3. To produce a net ton of pig iron 1757 lb. of coke was required in 1940 and 1760 lb. in 1939. These figures indicate how dependent the production of pig iron is upon the production of coke. The rate of iron production is in some measure influenced by the physical and chemical characteristics of the coke. Blast-furnace operators believe that the physical properties of coke profoundly influence the operation of the furnace. Although it is true that coke of a wide variety of physical properties is used in American blast furnaces, the periodic fluctuation of these properties is one of the causes of irregularity of blast-furnace operation. The purpose of this paper is to present a broad picture of the physical properties of by-product coke that are generally considered to be important by coke-oven and blast-furnace operators. Effects of the kind of coal used, the preparation of the coal, the rate of coking, and other factors will be considered. Of all these variables, the kind of coal used is by far the most important. In this discussion use will be made of the method of coal classification by rank1 standardized by the American Society for Testing Materials. Although this method of classification has been an American standard for several years, it has not been given the attention it deserves, especially in connection with the selection of coal for production of coke. Despite the fact that many producers of blast-furnace coke are limited to some particular source or sources of coal, a good understanding of the principles involved in setting up the standard method of classification may lead to a better appreciation of the causes of changes in coke characteristics. Furthermore, where it is necessary to select new coals as a substitute for the original supply, this method of classification can be of great assistance. The data presented have been gathered from many sources, but no attempt has been made to cover the vast literature. Instead, some of the more important data have been selected to show how coals and their carbonization affect some of the physical properties of coke. It must be emphasized that generalizations concerning the behavior of coking coals are presented and that individual coals may vary widely from the specific behavior depicted. Nevertheless, it is believed that the data illustrate certain typical behaviors. Neither was it possible to cover completely all the factors involved; for example, the macroscopic constituents of coal are believed to have important effects on the physical properties of coke, but since there is little information available for such study, and since vitrain, clarain, and durain are neither

Jan 1, 1943

By AIME

WE produce Charles Van Ormer "Charlie" Millikan as living proof that man need not make a loud noise to be heard. His quietly affable, analytical, and soft-spoken manner in the face of all problems belies his ability to "get tough" when the situation demands it. As a chief engineer with many responsibilities for the success of a large producing company there must have been many occasions to tempt Charlie to excitement, but there are few, if any, who can say they saw him yield. He has an abiding faith in the benefits of hard and persistent work and will not admit the existence of a problem that cannot be reduced by it.

Jan 1, 1948

By John Mills

THREE case histories from professions other than engineering will serve to introduce ideas basic to this discussion. Case (1) Date, about 1900. A young man, B. D. from a three-year graduate course in a prominent divinity school, was for two years a successful pastor of a small church; then friction over theological matters arose with a fundamentalist deacon of the "Bible belt" type. He resigned, returned to his university for a four-year medical course, interned for two more, and thereafter was successful and apparently happy as a physician. We may assume that he was converted in early adolescence and vowed himself to service as a minister. Acceptance of his announced career by parents, friends, and teachers plus his own determination confirmed his choice until illiberal criticism threatened his usefulness and he awoke to the fact that his inner needs were not along the direction in which inertia and his conscience had constrained him.

Jan 1, 1947

THE fifth annual convention of coal-operating men, with the usual exposition of coal-mine equipment, was held at Cincinnati, May 7 to 11 inclusive, and was fully up to the high standard set by previous years. This spring meeting has come to be one of the most helpful services to industry performed by the Ameri-can Mining Congress and a center at which operators and engineers easily and quickly get into touch with the newest and best things in practice and equipment. Over 200 exhibitors showed this year and very little if anything that is new `failed to be shown. The ex-hibits were well arranged and adequate rather than elaborate. They attracted the careful attention of the members and guests of the Congress, admission being by badge rather than by ticket sold to, the general public. Eight sessions were held for reading and dis-cussion of technical papers, one for Management and

Jan 6, 1928

(Members are urged 'to, send in for this column any notes of interest concerning themselves or, their fellow-members.) Members and guests who registered at Institute headquarters during the period Sept. 10 to Oct. 10, 1915: George H. Blakemore, Sydney, N. S. W. W. B. A. Dingwall, San Antonio, Tex.. H. Haege, Sydney, N. S. W. R. H. Jeffrey, London, England. C. A. Filteau, New York, N. Y. H. S. Emlaw, Spring Lake, Mich. Myron R. Walker, Cerro de Pasco, Peru. Y. T. Woo,' Tientsin, China. William R. Grunow, Morenci, Ariz. A. L. DeDeken, LouVain, Belgium. E. DeGolyer, Norman, Okla. K. P. Swensen, Tokyo, Japan. William W. Elmer, Tuttletown, Cal. Charles Enzian, Wilkes-Barre, Pa. Huntington Adams, Iquique, Chile. C. F. Schnepp, Cobalt, Ont., Canada. W. Ray Cox, for several years Mineral Inspector of the General Land Office at Portland, Ore., has been appointed Professor of Mining and Metallurgy in the School of Mines, Oregon Agricultural College, Corvallis, Ore.

Jan 11, 1915

By Edward H. Robie

AT a recent meeting of the AIME Board there was considerable discussion of a suggestion that companies should be more interested in promoting AIME membership among their employes. The advocate of this idea argued that companies benefit greatly if their employes are active AIME members, so even on purely a selfish basis they should use various means to encourage membership. Also he argued that companies in general make no contribution to the support of the AIMS although benefiting from its work, so should not object to making more of a contribution, financial or otherwise, than they do. One Director stated that an investigation had developed the fact that a large majority of members felt it unwise for employers to pay the initiation fees or dues of employes. They felt that AIMS membership should be on a purely personal basis; that the rewards of active membership were sufficient so that it is a good investment for a man in developing his own professional stature, presumably resulting in an increase in salary sooner, or in greater amount, than would otherwise be the case. If an employer paid a member's dues or initiation fee the member would take less interest in the Institute. But this Director felt that an employer should otherwise encourage his employes to join the Institute, attend its meetings, and write papers based on company work for presentation and publication. Another Director reported that his company pays the expenses of AIME members in its employ to meetings; the company also encourages nonmembers to attend AIME meetings but does not pay their expenses unless they present papers of interest to the company. Another Director, representing a supplier, stated that his company's policy was to send some of its staff to all AIME meetings at which papers of interest were to be presented or at which valuable contacts could be made.

Jan 1, 1952

By R. H. Doremus, E. F. Koch

The first carbide phase that precipitates at 120°C from a iron containing about 0.02 wt pct, C was studied with the electron microscope. In both strained and unstrained material the carbide particles appeared to form on the dislocations in the iron, in agreement with the results of the kinetic study in part II. The structure of the carbide was tentatively identified as an expanded a-iron lattice (body-centered tetragonal) with about 0.7 wt pct C. This phase appeared to be metastable and apparently transformed into cementite or epsilon carbide when the iron was over-aged. WhEN a iron containing less than about 0.025 wt pct C is quenched from 700°C to room temperature the carbon is retained in solid solution and precipitates out slowly with time. The morphology and structure of the precipitating phase are still in doubt, two different carbide phases, epsilon carbide and cementite, have been identified, but there is considerable disagreement about the time and temperature at which they appear.1-4 Epsilon carbide seems to form at lower temperatures than cementite, although one group of investigators4 found only the latter phase over a wide range of aging temperatures. Usually these two phases have been identified after aging times much longer than needed to drain the carbon from supersaturated solution, at least for aging temperatures below 200oC. The precipitated carbides have been observed with the electron microscope,'-5 but again most results have come from samples aged much longer than necessary to reduce the carbon concentration in solution to a low value. In this study the carbide phases were observed in earlier stages of precipitation with the electron microscope, in order to learn more about the shape, size, and distribution of the carbide particles. Samples strained small amounts before aging, as well as unstrained samples, were studied, and the structure of the carbide phase was tentatively identified. EXPERIMENTAL "Ferrovac E" vacuum-melted iron, from which the wires for kinetic studies were also made (Refs. 6 and 7 and the following paper) was used for this work. An analysis of this material is given in Table I; it agrees well with the manufacturer's values. The number of inclusions in the iron was very small, as can be seen in the optical micrograph in the following paper. Pieces of iron about 1 mm thick and 5 to 10 mm in diam were used for all the studies except for those in which the sample was strained before aging; then the specimen was a rod 3 to 6 mm in diam and 20 cm long. The samples were held at about 700°C in wet hydrogen for at least an hour to remove residual carbon and nitrogen, after which they were heated to 950" (in the y region) and cooled to room temperature in the furnace. This treatment gave an average grain diam of more than 1 mm, so that the effect of grain boundaries on the precipitation process was negligible. The samples were carburized at 710°C for about 2 hr in hydrogen that had passed over toluene held at -30°C; then they were rapidly quenched into water. From chemical analysis this treatment gave a carbon concentration of from 0.012 to 0.016 wt pct, which is less than the solubility of carbon at this temperature. After quenching, the samples were aged at 120 "C in an oil bath for vari-

Jan 1, 1961

By Wilfrid R. Foster

The industrial importance of the sillimanite group of minerals depends upon the beneficial properties exhibited by porcelains and refractories in which substantial amounts of these minerals are utilized as raw materials. The presence of "sillimanite" (now known to be the closely related mineral, mullite) in conventional porcelains and refractories has been known since before the turn of the century. As early as 1906 German investigators observed a direct correlation between the "sillimanite" content of a porcelain and its electrical and mechanical properties. Acting upon this discovery, U. S. Bureau of Standards investigators during World War I developed improved pyrometer tubes and spark plug porcelains, by increasing substantially the amount of "sillimanite" at the expense of quartz. The success of these experiments, first reported in 1918, at once aroused a lively interest in the location of natural sources of sillimanite and its related minerals. As a result of diligent search, the large andalusite deposits in California were discovered in 1919. Within the next several years large deposits of kyanite and sillimanite in India and kyanite in the United States had been reported. The search for these minerals in quantity, by both private and governmental agencies, has continued unabated during the ensuing forty years. A number of domestic deposits of kyanite have been worked during the past 30 years. Of these, only the Virginian and South Carolinian deposits are currently in substantial production. The only commercial andalusite production in the United States has been in California and Nevada. A dumortierite deposit in Nevada, known since 1917 but ignored for want of a commercial use, began production in 1925. A topaz occurrence in South Carolina has yielded a small production since about 1940. Domestic production of andalusite, dumortierite and topaz had virtually ceased by 1950. There has never been any commercial development of domestic sillimanite deposits. Kyanite has been mined almost continuously in India since about 1922. The remoteness of the large deposits of Indian sillimanite had caused it to be neglected until 1949. In that year sillimanite production began, and it has continued to the present. South African andalusite has been marketed from the 1930's until the present time. From 1944 to 1955 Kenya, British East Africa, was an important producer of kyanite. Commercial deposits of kyanite in Ontario, Canada should soon be in production. The first production of kyanite in Europe began in Austria in 1953. No commercial deposits of mullite are known anywhere in the world. It is of interest to note that synthetic mullite, which as "sillimanite" first elicited interest in the A12O3-rich aluminosilicate refractories, has enjoyed a marked increase in production in recent years. This is a result of the gradual depletion of known deposits of high-quality kyanite and related minerals."' Composition The sillimanite group includes kyanite, andalusite, and sillimanite, all having the same chemical composition (A12O3•SiO2) but different physical properties. Two other minerals, dumortierite and topaz, are also included in

Jan 1, 1960

By A.S. Richardson

AIR conditioning, or air cooling, for the improvement of ventilation in the Butte mines has come into increasing use during the past 10 years. In part, the methods practiced have been described in previous publications of the Institute, but some improvements on earlier methods have been made and a number of new features have been developed. This paper is presented as a record of progress made, and for the sake of completeness describes all general features of the work. The need for air conditioning in the ventilation of mines in the district arises from the fact that the temperature of the ground and mine water has shown a very great increase with increase in mining depth, and has now reached a maximum of slightly over 130°F. The most difficult part of the ventilation problem is the maintenance of temperature and humidity of a satisfactory standard in the working places, especially on the lower levels. Although ordinary ventilation is adequate to maintain good conditions in most of the working places it is subject to a number of limitations at great depth. Most important among these limitations is that with increase in depth the air becomes heated before it reaches the working places, both by compression from increase in atmospheric Pressure and by heat transferred to it from rock at high temPerature, so that its capacity for lowering temperatures is greatly reduced before it reaches the operating zone. Increasing depth of mining also increases the distance traveled by the air in its passage through the mine, and this causes a corresponding increase in resistance to air flow, so that there is greater difficulty in maintaining even the same volume in circulation. Thus, in the face of a demand that the ventilating system have a very much greater capacity to remove heat from the mine, the tendency is for that capacity to diminish. The only evident alternatives were (I) the opening of additional air shafts to increase the volume of air in circulation, (2) an extension of the existing system that would be subject to the same limitations, or (3) the adoption of an entirely different method such as air cooling. Fortunately for an economic solution of the problem, the mean annual temperature of the surface atmosphere at Butte is about 40°F., with very low relative humidity in summer, so that there is unlimited natural cooling power at a temperature range adaptable to air-conditioning methods. Methods Two similar methods of air conditioning are used, as necessitated by service requirements and dependent upon the equipment available. In one, which is the more important and has the greater cooling capacity, water is circulated in a closed circuit, and, alternately, first absorbs heat from warm mine air and then dissipates it in the surface atmosphere by cooling at a cooling tower. The second

Jan 1, 1943

By A. S. Richardson

AIR conditioning, or air cooling, for the improvement of ventilation in the Butte mines has come into increasing use during the past 10 years. In part, the methods practiced have been described in previous publications of the Institute, but some improvements on earlier methods have been made and a number of new features have been developed. This paper is presented as a record of progress made, and for the sake of completeness describes all general features of the work. The need for air conditioning in the ventilation of mines in the district arises from the fact that the temperature of the ground and mine water has shown a very great increase with increase in mining depth, and has now reached a maximum of slightly over 130°F. The most difficult part of the ventilation problem is the maintenance of temperature and humidity of a satisfactory standard in the working places, especially on the lower levels. Although ordinary ventilation is adequate to maintain good conditions in most of the working places it is subject to a number of limitations at great depth. Most important among these limitations is that with increase in depth the air becomes heated before it reaches the working places, both by compression from increase in atmospheric Pressure and by heat transferred to it from rock at high temPerature, so that its capacity for lowering temperatures is greatly reduced before it reaches the operating zone. Increasing depth of mining also increases the distance traveled by the air in its passage through the mine, and this causes a corresponding increase in resistance to air flow, so that there is greater difficulty in maintaining even the same volume in circulation. Thus, in the face of a demand that the ventilating system have a very much greater capacity to remove heat from the mine, the tendency is for that capacity to diminish. The only evident alternatives were (I) the opening of additional air shafts to increase the volume of air in circulation, (2) an extension of the existing system that would be subject to the same limitations, or (3) the adoption of an entirely different method such as air cooling. Fortunately for an economic solution of the problem, the mean annual temperature of the surface atmosphere at Butte is about 40°F., with very low relative humidity in summer, so that there is unlimited natural cooling power at a temperature range adaptable to air-conditioning methods. Methods Two similar methods of air conditioning are used, as necessitated by service requirements and dependent upon the equipment available. In one, which is the more important and has the greater cooling capacity, water is circulated in a closed circuit, and, alternately, first absorbs heat from warm mine air and then dissipates it in the surface atmosphere by cooling at a cooling tower. The second

Jan 1, 1943

By David Cole

AT the time flotation appeared upon the metallurgical horizon in Arizona, the writer, under the direction of Dr. Ricketts, was engaged in remodeling and enlarging the No. 6 Concentration Plant of the Arizona Copper Co. at Morenci, and the work had been in progress nearly a year before the Inspiration experiments with flotation had disclosed the revolution in concentration that was at that timè impending. The simplified flowsheet worked out for the remodeling of the Morenci plant had been based upon the removal of the freed metal in a minimum number of stages by treatment upon tables equipped with Butchart riffles, the latter being adapted to accomplish both classification of feed and removal of the metal at one operation, substantially as described in my previous paper.1 The scheme of treatment for the slime was based upon the well-known fact that after copper sulphides, such as chalcocite and chalcopyrite, etc., are reduced to a certain extremely fine state of comminution they are definitely beyond the reach of separation upon any of the concentrating devices then known. By using drag-belt classifiers (which served as conveyors as well as separators), the overflow would be of the usual "slimes" class. Experiment had shown that when these drag-belt overflows were, properly diluted (that is, to about 5 to 7 per cent. solids in the feed under treatment) . the very fine sand, and especially the very fine but still granular sulphide particle's, would, if given a short distance to fall, quickly settle out in prime condition to yield an excellent recovery on vanners; a further valuable feature would be that the very fine non-separable final overflow tonnage might be discharged direct to tailing, thus conserving space requirements so as to permit within the old building, without embarrass-ment, the increase of capacity required.

Jan 9, 1916

By U. C. Tainton

IN reviewing progress in zinc metallurgy during the last year or so one is reminded of the premise on which H. G. Wells based his "Food. of the Gods," namely that growth does not and cannot take place smoothly and steadily, but occurs in a series of bursts and intermissions: "It is as if every living thing has to accumulate force to grow, grows with vigor only for a time, and then has to wait for a space before it can go on growing again."

Jan 1, 1937

RECEIPTS [Magazine Advertising $ 62,564.83 Magazine Sales 3,591.44 Totalm 66,156.27 Dues, Arrears7,032.88 Dues. Current96,839.74 Dues, New Members6,525.00 Dues, in advance 1,907.02 Initiation Fees7,584.00. Sale of Transactions3,909.03 Sale of Binding7,845.05 Sale of Special Editions 338.20 Sale of Year Book76.20 Sale of Pamphlets1,189.06 Sale of Authors' Reprints867.54 Miscellaneous Receipts62.93 Interest on Bank Balances1,712.89 Interest on General Reserve Fund337.50 Interest on Life Membership Fund557.84 Interest on James Douglas Library Fund....5,491.89 Total Receipts$208,433.04] [ ]

Jan 1, 1925

Using 5-p Ni powder and 0.018 ,u A1203, oxide dispersion strengthened nickel alloys were prepared by mechanical mixing of powders, followed by compaction, sintering and extrusion. Processing variables such as cooling of the powder during mixing, electrostatic discharging, mixing time, amount of oxide, and so forth, were studied to determine the effects on room-temperature tensile and high-temperature creep-rupture properties and on the reproducibility of alloys. MECHANICAL mixing of metal and metal oxide powders provides one of the simplest and most inexpensive methods for preparing dispersion strengthened metal-metal oxide alloys;" however, because of large differences in specific gravity, powder particle diameters and other variables, difficulties have been encountered in reproducing alloys and alloy properties. Using 5-p Ni powder and 0.018 p A1203, the following variables were investigated: a) Blending techniques b) Blending time c) Volume fraction of oxide for the selected pow- ders d) Sintering of compacts before extrusion Cooling of Powders During Blending— Cremens and Grant had indicated that dry ball milling of the powder mixture gave superior results over other procedures. When ultra-fine metal and oxide powders became available and comminution was unnecessary or offered little gain, the use of dry mixing in a Waring Blendor gave optimum results.' In the current study, observations of the powder mixtures indicated that considerable heat was generated due to the high speed of the Waring Blendor (15,000 rpm). This heating appeared to produce some degree of clustering and pelletizing. To minimize such agglomeration, a Pyrex cooling coil was installed in the mixing vessel. A double coil, water cooled, proved to be quite satisfactory, providing a fair degree of cooling along with good erosion resistance. Discharge of Electrostatic Charge—Electron-microscopy showed that agglomeration was minimized by the cooling procedure but was not entirely eliminated. It appeared that some of the ag- glomeration had to be explained on the basis of an electrostatic attraction due to the high-speed blending operation. These charges had the effect of promoting the growth of alumina clusters. At the end of the blending procedure such clusters had an effective size which was as much as 50 times that of the individual powder particles and were very tightly bunched. Several methods were utilized to try to discharge the electrostatic forces to minimize the clustering. One successful method, utilized in alloy 17, involved continuous exposure during blending to a radium source of 50 millicuries at a distance of 1.5 ft from the container. A number of other methods were noted to work equally well. Fig. 1 shows the more open oxide structure which results from such a treatment, permitting the matrix metal to penetrate into the cluster more effectively. The combination of powder cooling and discharging led to noticeably improved structures. Fig. 2 shows a cross and a longitudinal section in alloy M-17, one of the best alloys, illustrating the marked decrease

Jan 1, 1961

EUGENE WESLEY SHAW,* Washington, D. C. (written discussion ?).-Studies of the probable future production of oil wells and fields-particularly those in the nature of the recent work by Lewis and Beal, having the object of increasing the percentage of recovery-rank, in both practical and theoretic value, very high, if indeed they do not outrank all other petroleum investigations except structural surveys. Even such surveys, although saving untold millions that might have been spent in prospecting unpromising territory, may have less ultimate value than generally supposed, for it may perhaps be argued that much if not most of the condemned territory will sooner or later be tested-some is already productive-and the most that can be rightly claimed is the recovery of cream first; also that the consumption of the richest portions first cannot be extenuated, as it might with some resources, on the ground that if the best is not taken now it will deteriorate.

Jan 5, 1918

Jan 1, 1920

By Elliot P. Rexford

B. C. Burgess-—Prior to hearing this paper presented at the San Francisco meeting, I travelled by car from Yuma, Ariz., across south-central California and up through the San Joaquin Valley. After hearing the paper I returned by the coast route to San Diego then along the Mexican border to Yuma. The striking feature of these trips, related to this paper, was the dry river and creek beds at a time of year not the dry season. Contrasted with this was the wasteful use of water in irrigation canals and laterals. Poland says "at least 90 pct of the ground water pumped is used for irrigation." That being the case, it would appear that first consideration should be given to conservation of this use. Probably a small part of this is actually reaching the plants. Some measure of this loss between pump and crops would be revealing. Methods that might be employed to reduce this loss are pipe lines and spraying of some crops such as the banana planters are using in Central America. Another idea which might be investigated is to line canals and ditches with some water-repelling mineral like pyro-phyllite. Perhaps a comparatively thin sprayed-on

Jan 1, 1951