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ently conflicting theories. The purpose of this paper is to show that these contributions not only do not conflict, but that all of them are essential parts of a picture, which is nearer completion than most of us realize. The main contributions may be summarized as follows:

Ritz showed that by assuming the nucleus to be magnetic, so that the force determining the vibration of the electron depends on the velocity instead of the position of the electron, one obtains a frequency law involving only the first power of the frequency, in accordance with observations.

The essential part of Bohr's beautiful theory is the mechanism by which he accounts for Ritz's combination principle namely, that the frequency of radiation depends not on where the electron is, or where it came from, but upon both.

J. J. Thomson added the idea that Bohr's stable orbits, and the quantum relations connected with them, are due to a skeleton struc ture of the nucleus and not to any discontinuity of energy.

Sommerfeld extended Bohr's theory to atoms of higher atomic weight, and has drawn a beautiful picture. His main contribution is the idea that the orbit may be either a circle or an ellipse of definite eccentricity, which accounts with extreme precision for the separation of doublets both in X-ray spectra and the hydrogen spectrum.

Langmuir showed that all known chemical properties are satisfied by an atom with relatively stationary electrons, arranged in concentric shells about the nucleus.

By combining these contributions, namely, the magnetic nucleus of Ritz, Bohr's stable orbits, Thomson's skeleton nucleus, Sommerfeld's elliptical orbits, and Langmuir's stationary electrons, we arrive at a composite picture which represents our present knowledge remarkably well. The rotating point electron is replaced by a ring-shaped electron. The constant angular momentum of the rotating electron is replaced by constant magnetic moment of the ring. In the case of hydrogen and ionized helium the ring sur

rounds the nucleus, and the picture is identical with Bohr's. In the case of the other elements the rings lie on the surface of concentric shells, in positions corresponding to Langmuir's cells. The condition of constant angular momentum of each ring electron holds for all atoms, and Sommerfeld's picture of the circular and elliptical rings is applied to the shape of the ring electron.

The discussion following the symposium was of necessity brief. Emphasis was given to the clear advantage of preferring a theory of atomic structure that gives correct quantitative results. G. W. STEWART, Secretary Section B


Ar the recent meeting of the academy the home secretary presented the following report: THE PRESIDENT OF THE NATIONAL ACADEMY OF SCIENCES.

Sir: I have the honor to present the following report on the publications and membership of the National Academy of Sciences for the year ending April 26, 1920.

Two parts of Volume 14 of the Memoirs of the National Academy of Sciences have been completed and distributed: the second memoir, "Complete Classification of Triad Systems,'' by H. S. White, F. N. Cole and L. D. Cummings, and the fourth memoir, "Minor Constituents of Meteorites," by G. P. Merrill.

The third memoir, "Tables of Minor Planets," by A. O. Leuschner, A. E. Glancy, and S. H. Levy, and the fifth and final memoir of Volume 14,

Tables of the Exponential Function," by C. E. Van Orstrand, are now in page proof and will be issued shortly, as will also Volume 15, "Psychological Examining in the United States Army,” by Robert M. Yerkes.

Volume 16, first memoir, "Lower California and its Natural Resources," by E. W. Nelson, and the second memoir, "Studies upon the Life Cycles of Bacteria," by F. Löhnis, are now in galley proof. The third memoir, "A Recalculation of Atomic Weights," by F. W. Clarke, is now in the hands of the printer.

Volume VIII. of the Biographical Memoirs has been completed with the publication of the biog

raphies of Benjamin Osgood Peirce, and Cleveland Abbe, and the bound volume distributed. The following biographies forming a part of Volume IX. have been completed and distributed: William Bullock Clark by John M. Clarke; Arnold Hague by Joseph P. Iddings; Eugene Waldemar Hilgard by Frederic Slate; James Dwight Dana, by L. V. Pirsson; James Mason Crafts, by Charles R. Cross; Lewis Boss, by Benjamin Boss, and Alpheus Spring Packard, by T. D. A. Cockerell. That of Charles Sedgwick Minot is now in page proof.

The Report of the National Academy of Sciences has been issued and the fourth Annual Report of the National Research Council will be issued in separate form in a few days. The Proceedings have reached the third number of the sixth volume. Since the last meeting, two members have died. Louis V. Pirsson, elected 1913, died December 8, 1919, and Horatio C. Wood, elected in 1879, died in 1919. This leaves an active membership of 175 members, 1 honorary member and 31 foreign associates. Gustav Retzius, foreign associate, died on July 12, 1919. C. G. ABBOT, Home Secretary


THE twenty-seventh summer meeting and ninth colloquium of the American Mathematical Society will be held at the University of Chicago during the week beginning Monday, September 6, 1920. The sessions of the Mathematical Association of America will occupy Monday morning and afternoon. The council of the society will meet on Monday evening. The regular sessions of the society will occupy Tuesday morning and afternoon and Wednesday morning. The joint dinner of the society and the association will be held on Tuesday evening.

The University of Chicago will open two of its dormitories, one for men and one for women, during the week of the meeting, and meals will be provided on the university grounds. Advance information on these matters can be obtained from Professor H. E. Slaught.

The colloquium will open Wednesday afternoon and will extend through Saturday morning. It will consist of two courses of five lectures each, as follows: I. Professor G. D.

Birkhoff, of Harvard University: "Dynamical systems." The last forty years have witnessed fundamental advances in the theory of dynamical systems, achieved by Hill, Poincaré, Levi-Civita, Sundman, and others. The lectures will expound the general principles underlying these advances, and will point out their application to the problem of three bodies as well as their significance for general scientific thought. The following topics will be treated: Physical, formal, and computational aspects of dynamical systems. Types of motions such as periodic and recurrent motions, and motions asymptotic to them. Interrelation of types of motion with particular reference to integrability and stability. The problem of three bodies and its extension. The significance of dynamical systems for general scientific thought.

II. Professor F. R. Moulton, of the University of Chicago: "Certain topics in functions of infinitely many variables." I. On the definition and some general properties of functions of infinitely many variables. II. On infinite systems of linear equations. III. Infinite systems of implicit functions. IV. Infinite system of differential equations. V. Applications to physical problems.


A MEETING of the council of the American Association for the Advancement of Science, held in Washington on April 26, approved the organization of the Southwestern Division of the Association, which was tenatively made in a meeting of delegates held at the University of Arizona, Tucson, Arizona, on Saturday, April 10.

At that meeting Dr. D. T. MacDougal was delegate from the American Association. Local delegates came from Prescott, Phoenix, and Tucson, Arizona Albuquerque, New Mexico and El Paso, Texas.

Dr. Edgar L. Hewett, of the School of American Research, director of the Archaeological Institute, director of the State Museum at Sante Fe, N. M., and the Archaeo

logical Museum in San Diego, was elected president of the Southwestern Division; Elliott C. Prentiss, M.D., of El Paso, Texas, was elected vice-president and chairman of the executive committee; and Dr. A. E. Douglass, of the University of Arizona, was elected secretary and treasurer.

The executive committee in its membership besides the three officers just mentioned consists of Dr. John D. Clark, Albuquerque; A. L. Flagg, Phoenix; Fabian Garcia, Mesilla Park; Arthur Notman, Bisbee; Richard S. Trumbull, El Paso; Milton Updegraff, Prescott; and Charles T. Vorhies, Tucson.

A constitution was adopted. The area included in this Division will be Arizona, New Mexico and West Texas.

Dr. Edgar L. Hewett, the newly elected president of the Southwestern Division, gave a lecture entitled "Our Place in Civilization," at the University of Arizona, Tucson, on April 28 and at El Paso, Texas, on April 30. In connection with the formation of this division also Dr. A. E. Douglass, of the University of Arizona, gave a lecture entitled The Big Tree and its Story," in Phoenix, Arizona on April 1.

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DR. HENRY S. DRINKER has addressed to his fellow-alumni of Lehigh University, the following letter:

I have felt for some time and have so stated, informally, to the members of our board of trustees, that as I reach the age of seventy this year, it would be the part of wisdom for me to retire from the presidency of the university. I have therefore tendered my resignation to take effect at the close of the commencement exercises on June 15th next. So far as I know, I am in perfect health and in good strength, but I wish to retire while my friends still feel they desire my services to continue. I am not willing to hold on for some time, as I might do, and then feel that increasing years and failing powers compel my retirement.

From the time of my graduation in June, 1871, I have been devoted to the service of the university's interests, and have served as secretary of the alumni, president of the alumni, alumnus trustee, trustee and president, and now in proposing to

drop out of active presidential duties, I have no thought of lessening my interests in the alma mater, nor is my retirement from the presidency prompted by any thought except that I have accomplished the things for which I came here, and I now wish to see the leadership of the university pass into the hands of a younger man, one qualified by educational training and actual large experience in edu cational work, and possessing marked executive ability. I am satisfied that the university has reached a stage in its existence requiring for its leadership and guidance, a man possessing these characteristics.

It has been my privilege to bring to the service of the university energy, devotion and business experience. It was thought at the time of my election, when the university was in financial strain, and in need of greater facilities in plant and equipment and a larger teaching force, that the energies of its friends should be directed to these ends, and I was asked to undertake the task. To-day, with our plant in greatly improved shape, with our fac ulty increased from 15 in 1905, to 33 in 1920, the entire teaching force raised from 57 to 89, with our financial situation greatly improved and comparing favorably with that of our competitors, our present need is, as above stated, for a man experienced and trained in educational methods, and with good executive ability; I feel content in the knowl edge that our board of trustees will well consider the situation, and fittingly serve our university's needs.

SCIENTIFIC NOTES AND NEWS Ar the recent meeting of the National Academy of Sciences the following foreign associates were elected: Frank Dawson Adams, McGill University; Marie Ennemond Camille Jordan, Collège of France; François Antoine Alfred Lacroix, Musée d'Histoire Naturelle, Paris; Heike Kamerlingh Onnes, University of Leyden; Sir David Prain, Royal Botanic Gardens, Kew, Surrey; Santiago Ramon y Cajal, University of Madrid.

THE National Academy of Sciences has recommended to Columbia University that the Barnard medal be conferred on Albert Einstein "for highly original and fruitful development of the fundamental concepts of physics through the application of mathematics." The Agassiz medal has been awarded to Admiral C.

D. Sigsbee, U. S. N., retired, "for his important contributions to oceanography, both by actual research, by publication of his results and invention of new methods."

IN recognition of successful scientific research in the prevention of disease and the conservation of health, Dr. Theobald Smith, head of the Laboratory of Comparative Pathology of the Rockefeller Institute and formerly of Harvard University, has been voted the M. Douglas Flattery Medal and $500 in gold by the Harvard Corporation. The medal is awarded to the man of science whose efforts have proved of the greatest value to mankind in fighting disease.

A PORTRAIT of Dr. William H. Welch, of the Johns Hopkins University, president of the University Club of Baltimore, was presented to the club recently at its monthly meeting.

DR. W. W. KEEN has been elected an honorary fellow of the Royal Society of Medicine, London, and of the American Surgical Association.

DR. RAYMOND F. BACON, director of the Mellon Institute of Industrial Research of the University of Pittsburgh, who during 1918, was a colonel serving as chief of the Technical Division of the Chemical Warfare Service, A. E. F., has been awarded a citation by General Pershing for exceptionally meritorious and conspicuous services in France.

PROFESSOR SADAO YOSHIDA, of Osaka Medical College (Japan), has been awarded the Katsurada prize and medal of honor established by the Japanese government to be given periodically to some distinguished worker on tropical diseases. Professor Yoshida is spending his sabbatical year in research at the Parasitological Laboratory of the University of Illinois.

MR. VILHJALMUR STEFANSSON has been awarded the La Roquette Medal of the Geographical Society of Paris. He had previously been awarded the following medals: In December, 1918, the Daly Medal of the American Geographical Society, New York; in December, 1918, the medal of the Explorers

Club of New York; in January, 1919, the Hubbard Medal of the National Geographical Society, Washington; in January, 1919, the Kane Medal of the Geographical Society of Philadelphia; in March, 1919, the Cullum Medal of the Chicago Geographical Society. All these medals are known as gold medals but at Mr. Stefansson's request they have been struck in bronze and the difference in cost has been given to Madame Beuchat, the mother of the distinguished scientific man, Henri Beuchat, who died on the expedition.

PROFESSOR KONRAD ROENTGEN retired from his chair of experimental physics at the University of Munich and resigned the charge of the Physikalisches Institut at the end of the winter semester.

THE board of trustees of the University of Pennsylvania has accepted the resignation of Provost Edgar Smith to take effect June 30. Dr. Smith presented his resignation last February. In accepting it now the board made him emeritus professor of chemistry and placed at his disposal the Harrison laboratory, where Dr. Smith expects to devote the greater part of his time to research work.

DR. EDWARD T. REICHERT, professor of physiology in the Medical School of the University of Pennsylvania, has retired from active. service.

Ar the annual meeting of the Kentucky Academy of Science held in Lexington on May 8, the following officers were elected: President, Professor W. H. Coolidge, Centre College, Danville, Ky.; Vice-President, Professor George D. Smith, Eastern Kentucky State Normal School, Richmond, Ky.; Secretary, Dr. A. M. Peter, Experiment Station, Lexington, Ky.; Treasurer, Mr. J. S. McHargue, Experiment Station, Lexington, Ky.

DR. A. HRDLIČKA, of the U. S. National Museum, has returned from a trip to the Far East He visited Japan, Korea, Manchuria, northern China and Hawaii.

MR. IRVING PERRINE, vice-president of the American Association of Petroleum Geologists, is moving his office from Hutchinson, Kansas, to 1415 West 31st Street, Oklahoma City,

Okla., and will there continue his work as a consulting petroleum geologist.

DR. IRA REMSEN, of the Johns Hopkins University, will deliver the commencement address at West Virginia University on June 15. DEAN W. M. WHEELER, of Bussey Institution, Harvard University, delivered an address under the auspices of the Society of Sigma Xi of Syracuse University, on May 6. The address, which was on "Worm-lions, ant-lions and some eighteenth-century entomologists," covered the observations made by Réaumur and other early naturalists upon the habits of the worm-lion and ant-lion; and included the studies of the lecturer upon the structure and behavior of the worm-lions of California.

DR. G. M. STRATTON, professor of psychology at the University of California, has given the Nathaniel W. Taylor lectures at the Yale School of Religion.

DR. GEORGE F. KAY, head of the department of geology, State University of Iowa, and state geologist of Iowa, lectured on April 21 before the chapter of Sigma Xi of the University of Minnesota, on "The History of Glaciation in the Mississippi Valley."

DR. C. E. KENNETH MEES, director of the research laboratories of Eastman Kodak Co., landed in England April 27. While there

he will deliver the following lectures before

various scientific bodies: "Some Photographic

Phenomena in Relation to Astronomy," "Some Results of Recent Investigations on the Theory of Development," "Photography of the Air," "Reaction of the Eye to Light,” "A Photographic Research Laboratory," "The Production and Supply of Synthetic Organic Chemicals in the United States," "Rochester and the Kodak Works," "Scientific Research and Industrial Production," "The Theory of Tone Reproduction with a Graphic Method for the Solution of Problems."

DR. HARRY N. HOLMES, head of the chemistry department of Oberlin College and chairman of the National Research Council's ComImittee on Colloids is on a five weeks lecture tour to the Pacific coast. The series of from one to four lectures on "Colloid Chemistry"

will be given at Northwestern University, Los Angeles, San Francisco and Seattle Sections of the American Chemical Society, University of Washington, State College of Washington, Montana School of Mines, Montana State College, State College of North Dakota, University of Wisconsin, Iowa State College (Ames), Leland Stanford University and the University of California.

DR. JOSEPH SIMMS, a well-known lecturer and traveler, who died of cerebral hemorrhage in New York City on April 11, in his eightyseventh year, bequeathed his body to Dr. Edward A. Spitzka for scientific study. The brain of Dr. Simms, removed eighteen hours after death, weighed 1,520 grams (53.58 onces avoirdupois) and has been preserved by Dr. Spitzka for the detailed study of its morpho logic features in comparison with the brains of other notable men.

IT is stated in Nature that botanists in Great Britain have been considering the prac ticability of holding an Imperial Botanical Congress in London at which botanists from the overseas Dominions might meet their colleagues at home for the discussion of matters of common interest. Many subjects are ripe for discussion, such as the methods of training botanists for service abroad, the relation between the pure science and its ap

plications and between the botanist and the

commercial men interested in industries in which botanical knowledge should play an important part, more helpful cooperation between the home and the overseas botanist, botanical surveys of overseas Dominions, and others. After careful consideration it has been decided that it would be inadvisable to hold such a congress during the present year.


THE medical departments of Columbia, Harvard and the Johns Hopkins Universities receive $5,541,401 each, in the distribution of the estate of Captain Joseph R. De Lamar. The will, disposing of a sum of thirty-two million dollars, provides these funds for the study and

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