The preponderance of environmental evidence seems to indicate that rock flowage is the distinctive kind of movement, but so many qualifications, definitions and assumptions enter into this conclusion that my present inclination is to keep firmly in mind the complex facts of deformation in our zone of observation as a possible key to the interpretation of unseen movements. This attitude will require us to pay more attention than heretofore to the possibilities of heterogeneous structural behavior at great depths. Particularly should we keep in mind the fact that the kind of rock flowage accomplished experimentally produces structures which in the earth have sometimes been called fracture or combined fracture and flowage. We may assume a downward extension of combined fracture and flowage, as observed in the field, and still meet the conditions of flow implied by experiment.

How Are Stresses Transmitted in the Deep Zone?-In our zone of observation stresses are clearly transmitted by the competent members of the lithosphere. In any area of deformation evidence may usually be found of the control of the structure by one or more competent members. When the notion was widely held that the interior of the earth was molten or fluidal, hydrostatic stress conditions were naturally assumed. With the later knowledge that the earth acts essentially as a solid throughout, this view was largely abandoned in favor of the view that rocks in the deep zone act as rigid competent members capable of transmitting stresses in definite directions. The vector properties of cleavage and other structures supposed to develop in this zone were cited to indicate the definite orientation of stresses. It does not follow from this, however, that pressure conditions were or are not hydrostatic, especially under slow movements. Rocks under compression from all sides greater than their crushing strength seem to transmit stresses in a manner suggesting approach to hydrostatic conditions of pressure. When the stress differ

ences

are such as to require it, there is movement in the direction of easiest relief. The stress as reflected by the movement would seem to have been transmitted in a definite direction, and yet the pressures may have remained hydrostatic. If we were to imagine a volume of liquid deep below the surface subjected to differential stress sufficient to deform its containing walls, it is clear that the movement would be in the direction of easiest relief, notwithstanding the hydrostatic conditions within the liquid. Periodicity of movement is possible under this conception. Rock structures indicate movement only, not necessarily the inherent stresses. Movement of rocks under the conditions supposed to obtain deep below the surface seems likely to be at least in part a matter of relief of materials so contained between rigid members that the direction of escape is definitely oriented. Of course this supposition assumes that on some scale, small or large, there are units of mass competent to act as retaining walls for materials acting under hydrostatic pressure. If all the mass in the deep zone were under hydrostatic pressure, the retaining walls might be regarded as the solid shell above, inequalities in the competence of which would control the movements in the direction of easiest relief. However, rock structures, such as cleavage and folds, with vector arrangement of the sort observed near the surface and of the sort supposed to exist below, tell us only of the direction of movement and fail to indicate whether the stresses are hydrostatic or otherwise.

CONCLUSION

Within the zone accessible to observation movements of rock masses are accomplished by fracture and flowage. These processes may be distinct and separate, or so interrelated as to make definition difficult. The zones of movement are many, their positions and attitudes diverse. In general they indicate shearing or grinding movements between rock masses, accomplished both by fracture and flowage, and caused by stresses inclined to

the zones of movement. This conception is taken to afford the best initial basis for the interpretation and correlation of observed rock structures. There is no certain evidence of increase or decrease of movement toward the bottom of this zone. Beyond a shallow surface zone, there is no certain evidence of increase of rock flowage and decrease of rock fracture with depth. There is no certain evidence that rock flowage means greater weakness than rock fracture. There is no certain evidence in rock flowage that pressures are dominantly hydrostatic or dominantly those of competent solid bodies.

Movements are known to occur in the zone below our range of observation, but their nature and distribution are the subjects of varied hypotheses based on a few known conditions. Much of the sharper diastrophism seems to be confined to a thin surficial zone. Deeper movements, of a more massive type, periodic, and possibly slower, seem to be implied by the relative movement of great earth segments as represented by continents and ocean basins. Their depth is unknown. Most of the current hypotheses agree in assuming a single mobile zone in which rocks move dominantly by rock flowage. The basic requirements of reasonable hypothesis, however, may be equally well met by a conception of movement much like that of the zone of ob

servation. This does not require or postulate the conception of the existence of any single mobile zone, or zone of slipping, or zone of flowage, or of an asthenosphere. It supposes movement irregularly distributed in many zones, with any inclination, and

accom

plished by both fracture and flowage as far below the surface as movement extendsalways remembering that some of the structures geologically described as fractures, may be expressions of mass movement of the kind defined as flow in experimental results.

Conditions of temperature and pressure and vulcanism become more intense with depth, but it remains to be shown that their conjoint action results in a uniform environ

ment, and even if it does, that this condition is not upset by what might be called a heterogeneity of the time factor as represented by differing rates of deformation. If homogeneous environmental and time conditions are assumed, it is yet to be shown that these are sufficient to overcome the heterogeneity of the physical properties of the rocks and to cause homogeneous behavior through any considerable zone. It is not even certain that they may not fix and accentuate the heterogeneous properties of rocks. Certainly in the zone of observation there is comparatively slight evidence of their efficacy in causing more uniform deformation with depth.

In short, as between alternative conceptions as to the conditions in the deep zone, the burden of producing affirmative evidence would seem to rest heavily on any conception involving radical departure from the known irregular distribution and manner of movement within our zone of observation. We come, therefore, to the Chamberlin conception of a heterogeneous structural behavior of the earth. C. K. LEITH

UNIVERSITY OF WISCONSIN

SCIENTIFIC EVENTS

DINNER IN HONOR OF THE RETIRING
SECRETARY OF AGRICULTURE

THE success of Secretary E. T. Meredith in interesting the public in the investigational work of the U. S. Department of Agriculture has been unique. His prompt recognition of the needs of the department and his activity in behalf of the investigators there, have attracted the attention of scientific men throughout the country. Coming to the secretaryship at a time when the morale of the scientists in many government departments was being seriously impaired through discouragement as to the possibility of securing adequate support for investigation, his campaign of education had the effect both of awakening the public to the extent and importance of the work, and of heartening the workers.

It was then appropriate that before his retirement, there should be some demonstration of appreciation by the scientists themselves. This took the form of a buffet supper at the Raleigh Hotel, Washington, February 16. The event was planned by a committee chosen from the membership of the various Washington scientific societies in which the Department of Agriculture is largely represented. In the menu were included various items representative of the work of the department, such as Dasheen Chips," ""Soy Bean Sauce," "American Roquefort Cheese," and "New Unnamed Grapes." During the evening, Dr. B. T. Galloway presented Secretary Meredith with a vellum volume bound in hand-tooled, dark morocco, and containing the following inscription of appreciation signed by the five hundred and sixty scientific and technical men who attended:

The researches of the United States Department of Agriculture in recent years have become so diversified and so important for the welfare of the country and are so absolutely dependent on a wise, far-seeing and sympathetic administration, such as you have given us, that your departure from among us is a matter of very general regret.

Your broad comprehension and appreciation of the fundamental importance of scientific research in agriculture, your prompt recognition of the needs of the service and your enthusiasm and effective efforts to secure proper recognition of the work and workers have been most stimulating to us and have been of the greatest value in promoting a better understanding of the activities and purposes of the department and their vital relation to the business and industrial interests of the nation and the progress of the whole people.

In view of the above facts, we the undersigned, desire to express our deep appreciation and to thank you for what you have done and extend to you our hearty good wishes for all time to come.

In response, the secretary spoke briefly of his interest in the scientific work of the department, and his hopes for its future development. The esteem in which Mr. Meredith is held, was evidenced by the large attendance at this unofficial gathering. And the spirit of those present was such that when all joined in a rousing cheer for "Meredith" and

in singing “ He's a jolly good fellow" it seemed not only wholly in harmony with the occasion, but a fitting expression of their enthusiasm for the man.

CONGRESS ON MEDICAL EDUCATION

THE Annual Congress on Medical Education, Licensure, Hospitals and Public Health will be held at Chicago on March 7, 8, 9 and 10, under the auspices of The Council on Medical Education and Hospitals, and The Council on Health and Public Instruction of the American Medical Association, The Association of American Medical Colleges, The Federation of State Medical Boards of the United States and The American Conference on Hospital Service.

The program of the sessions on Medical Education are as follows:

Introductory Remarks, Arthur Dean Bevan, chairman of the Council on Medical Education and Hospitals, Chicago.

The Significance of Group Practise in its Relation to the Profession and the Community, Veader N. Leonard, Academy of Clinical Medicine, Duluth.

SYMPOSIUM ON GRADUATE TRAINING IN THE VARIOUS MEDICAL SPECIALTIES

Medicine and the Medical Specialties— (a) Internal medicine, George Blumer, clinical professor of medicine, Yale University.

(b) Pediatrics, Harry M. McClanahan, professor of pediatrics, University of Nebraska. (c) Nervous and mental diseases, Arthur S. Hamilton, professor of nervous and mental diseases, University of Minnesota. (d) Dermatology and syphilology, William A. Pusey, emeritus professor of dermatology, University of Illinois.

Surgery and the Surgical Specialties(a) Surgery, Charles H. Frazier, professor of clinical surgery, University of Pennsylvania.

(b) Ophthalmology, Walter B. Lancaster, Boston.

(c) Oto-Laryngology, Wendell C. Phillips, New York.

(d) Orthopedic surgery, Robert W. Lovett, professor of orthopedic surgery, Harvard University.

(c) Urology, Hugh H. Young, clinical professor of urology, Johns Hopkins University. The Relation of the General Practitioner to the Specialist, James B. Herrick, professor of medicine, Rush Medical College. Obstetrics and Gynecology, J. Whitridge Williams, dean and professor of obstetrics, Johns Hopkins University.

Public Health and Hygiene, Victor C. Vaughan, dean and professor of hygiene and physiological chemistry, University of Michigan. Preclinical Subjects

(a) Anatomy, Albert C. Eycleshymer, dean and professor of anatomy, University of Illinois.

(b) Physiology, Joseph Erlanger, professor of physiology, Washington University.

(c) Pharmacology and therapeutics, Charles W. Edmunds, professor of materia medica and therapeutics, University of Michigan. (d) Pathology and bacteriology, James Ewing, professor of pathology, Cornell University.

Summary of Reports on Graduate Training in the Specialties, Louis B. Wilson, chairman of the Council's Committee on Graduate Medical Education, Rochester, Minn.

THE MANUFACTURE OF CHEMICALS FOR

RESEARCH WORK

To reduce the cost of chemicals needed for research work in various scientific departments of the University of Wisconsin, the chemistry department will give a new course in the manufacture of organic chemicals during the summer session under the direction of Professor Glenn S. Skinner. The only other course of this kind given anywhere in the country is at the University of Illinois.

Professor J. H. Mathews states that most of the chemicals now available for experimental work are obtained only at excessively high prices and the department is compelled to make the choice between excessively high laboratory fees or curtailment of laboratory instruction. It will be possible with the laboratory facilities available during the summer months to manufacture these chemicals more cheaply than they can be purchased, thus materially cheapening the cost to the student.

All men of science in the university have

been asked to leave their orders for chemicals with Professor Skinner and as far as is possible these orders will be filled by his course.

Only eight advanced students will be admitted to the course, and they will work from nine to ten hours a day and will receive about 40 cents an hour for their work. Only the most promising graduates and upper classmen will be selected for the work, with the view to giving them intensive training in practical organic chemistry and experience in larger scale operations.

INSTITUTE FOR FOOD RESEARCH AT STANFORD UNIVERSITY

THE Carnegie Corporation of New York announces that it has entered into an agreement with Leland Stanford Jr. University, by which a food research institute is to be established at the university for the intensive study of the problems of production, distribution and consumption of food. The corporation expressed hope that the new organization will in time be known as the Hoover Institute.

Need for such an institution was first suggested to the corporation by Mr. Herbert Hoover, former food administrator and a trustee of Stanford University. The selection of Stanford was due in part to the fact that there is deposited there documentary material relative to the economic side of the war gathered by Mr. Hoover. He will serve as a member of the advisory committee.

The institute will begin work July 1. The corporation will provide $700,000 for its support for ten years.

The university has agreed to make its scientific laboratories available to the institute. It is not intended to duplicate the equipment of research laboratories working in the field of nutrition, but to cooperate with other agencies.

Need for continual research work in problems arising after food has left the farmer's hands was emphasized by experience during the war, it is explained, when the study of food supply was necessary to attain maximum efficiency in the nutrition of the nations involved. During the war much of the previous data regarding food was found to be inaccurate. It

now is hoped to eliminate waste through scientific research.

Under the terms of the agreement Leland Stanford will appoint three scientific men, with authority to determine policies and problems to be studied. There also will be an advisory committee of men of national prominence, representing agriculturists, consumers, business men and other groups. The university will appoint seven members of this body to serve with the president of the university and the president of Carnegie Corporation, ex officio, for a term of three years.

SCIENTIFIC NOTES AND NEWS THE Bruce gold medal of the Astronomical Society of the Pacific has been awarded for the year 1921 to M. Henri Alexandre Deslandres, director of the Astrophysical Observatory of Meudon, France, for his "distinguished services to astronomy."

PROFESSOR JULES BORDET, to whom the Nobel prize in medicine was recently awarded, has been elected a member of the senate of Belgium

from the Hainaut district.

WE learn from Nature that at a meeting of the award committee, consisting of the presidents of the principal British engineering institutions, the first triennial award of the Kelvin gold medal was made to Dr. W. C. Unwin, who was, in the opinion of the committee, the most worthy to receive this recognition of preeminence in the branches of engineering with which Lord Kelvin's scientific work and researches were closely identified. The Kelvin gold medal was established in 1914 as part of a memorial to the late Lord Kelvin and in association with the window placed in Westminster Abbey in his memory by British and American engineers.

GEORGE C. WHIPPLE, professor of sanitary engineering in the Harvard Engineering School, has been elected a fellow in the Royal Institute of Public Health.

THE Medical Society of the City and County of Denver has appointed a committee to plan a meeting in appreciation of Dr. Hubert Work,

Pueblo, the president-elect of the American Medical Association.

DR. J. M. ALDRICH, of the U. S. National Museum, was elected president of the Entomological Society of America at the Chicago meeting.

PROFESSOR GEORGE A. DEAN, of the Kansas State Agricultural College, was elected president of the American Association of Economic Entomologists at its recent annual meeting in Chicago.

DR. W. R. G. ATKINS, of Trinity College, Dublin, has been appointed head of the department of general physiology at the Plymouth Laboratory of the Marine Biological Association.

WE learn from the Journal of the Washington Academy of Sciences that Mr. W. F. Wallis, of the department of terrestrial magnetism, Carnegie Institution of Washington, left Washington on January 9 for Huancayo, Peru, where he will succeed Dr. Harry M. W. Edmonds as magnetician-in-charge of the Huancayo Magnetic Observatory upon the conclusion of the latter's two-year assignment. Dr. Edmonds will return about April via San Francisco for duty at Washington.

DR. H. L. SHANTZ has been appointed plant physiologist in charge of plant physiological and fermentation investigations in the Bureau of Plant Industry. Dr. Shantz returned in September from a year's trip through Africa for the Office of Foreign Seed and Plant Introduction.

MR. A. D. WILSON, who has been director of agricultural work for the University of Minnesota for the past twelve years and superintendent of Farmers' Institutes for the State of Minnesota for the past fourteen years, has resigned these positions to take up farming in northern Minnesota, the resignation being effective on June 30.

MR. W. H. KENETY, who has been assistant professor of forestry in the University of Minnesota and superintendent of the Forest Experiment Station at Cloquet for the past eight years, has resigned to take a position