subject to severe criticisms-(a) the observed rate of energy transformation is greater in the giant than in the hotter and denser dwarf stars; (b) the adiabatic nature of a star would be insufficient to regulate the generation of heat.

Jeans assumes that we have, in the center of stars, a quantity of atoms of atomic weight higher than uranium, whose super-radioactive powers lead to decomposition into energy. The success of the theory in accounting for the following observed facts is enough to demand its serious consideration.

1-Life of stars of order of 1013 years

2-Better value of the stellar absorption coefficient 3-Giant and dwarf stars

4-White dwarfs

5-Early spectral type of spectroscopic binaries 6-Relations between visual double stars

7-Sufficiently long time for evolution of orbits of

visual binaries

8-Cepheid and Long Period Variables (?)

the work of an investigator in his chosen field of spectroscopy, receiving the degree of Ph.D. in 1895. His thesis, on the infra-red spectra of certain metals, represented practically the first accurate measurements of infra-red lines. His knowledge of astronomy and astrophysics, in addition to his attainments in physics, led, in 1895, to his being called to the University of California, where a physicist was needed who could give proper support to the astronomical work being undertaken on the campus at Berkeley in connection with the work at Lick Observatory. At the University of California he held the position of instructor in physics from 1895 to 1896; assistant professor from 1896 to 1902; associate professor from 1902 to 1908; professor from 1908 to the time of his death, serving after 1918 as the chairman of the department. From 1898 to 1900 he was on leave of absence on a Whiting Fellowship, engaged in spectroscopic research at the University of Berlin, making a systematic investigation of the effects produced by small quantities of other substances in the spectra

LICK OBSERVATORY,

Nov. 25, 1926.

DONALD H. MENZEL

EXUM PERCIVAL LEWIS

In the death of Exum Percival Lewis on November 17, 1926, there was lost to science an inspiring teacher, a distinguished investigator in spectroscopy and astrophysics, a philosopher and an idealist. Professor Lewis was born in Washington County, North Carolina, on September 15, 1863. He was the son of Henry Exum Lewis, a noted physician, and Emma (Haughton) Lewis. Owing to the privations brought by the Civil War and to the death of his father when he was seven years old his elementary education was obtained entirely at home. As a boy he served as a printer's apprentice and as a young man accepted a position in the War Department at Washington, D. C. While thus employed he attended night classes at Columbian University (now George Washington University) from which he was graduated in 1888 with the degree of B.S. In 1890 he entered the Johns Hopkins University as a graduate student in physics, mathematics and astronomy, and from 1891 to 1895 he was an assistant in physics at that institution, having charge of the laboratory instruction. At the same time, from 1892 to 1895, first as instructor and then as assistant professor, he lectured evenings on general physics, electricity and heat, in the scientific school of Columbian University.

At Johns Hopkins University, under the inspiration of Professor Rowland, Professor Lewis began

found the first recognition of the fact, which has only recently been fully recognized, that the most profound changes in the character and appearance of the spectrum of a given element or substance can be produced by suitably modifying the excitation. It was in connection with this investigation that, in 1900, he discovered the afterglow in a vacuum tube containing nitrogen in which a slight trace of oxygen or water vapor was present. In 1904 he discovered the ability of this afterglow to excite the spectra of various solid substances introduced into the nitrogenfilled tube: this secondary excitation also persisting after the main discharge had ceased. These phenomena, extended by Lord Rayleigh and others, under the term "active nitrogen," have become of great importance. In addition to his researches in active nitrogen he investigated the band spectrum of nitrogen, especially the second positive group in the ultraviolet. His discovery of the effect that the introduction of self-induction in the circuit has on the band spectrum of nitrogen is still one of the most striking examples of what is now known to be the effect of changes in temperature upon any band. Among his other contributions to spectroscopy was the discovery of the continuous spectrum of hydrogen in the ultraviolet, with a determination of its limits and the condition most favorable to its production; the determination of several hundred new lines in the ultraviolet spectra of krypton and xenon; and the ultraviolet spectrum of the solar corona obtained with a quartz spectrograph of his own design. This spectrograph was made possible by a special grant from the Carnegie Institution.

His papers in physics, in other fields than spectroscopy, are numerous and include such subjects as the ionization of gases, conduction of electricity in gases, changes in length and hysteresis losses accompanying magnetization, the mechanism of light emission, the pressure of sound waves and a method of determining amplitudes in sound. His interest in the teaching of physics led him to contribute largely to this subject, through addresses before educational conventions and through publication.

Professor Lewis was strongly attracted to astronomy, especially on the astrophysical side. He was a member of the Crocker Eclipse Expeditions of the Lick Observatory in 1908 at Flint Island in the South Seas, in 1918 at Goldendale, Washington, and in 1923 at Ensenada, Lower California. His special part in these expeditions was the study of the corona. His photographs showed the continuous spectrum of the inner corona from 15500 to 13175, with a number of bright lines, which had not been previously observed, superimposed. His observations led to the conclusion that the temperature of the inner corona probably exceeded 2,000° absolute. Professor Lewis was a teacher of rare charm. He had the power of separating the essentials from a mass of confusing details and presenting the material with clearness and an absorbing interest. He was sympathetic and patient, allowing great freedom to students and colleagues associated with him, but demanding always a high standard of scholarship. He imparted to the students enthusiasm and high ideals. With many of the present methods of education he was in outspoken opposition, maintaining that they tended to develop mediocrity rather than the highest attainment possible. He was unusually gifted with the power of popular exposition, presenting technical and difficult conceptions in physics and astronomy with a clearness and simplicity that appealed to the layman and brought to his hearers a fuller appreciation of the interest and value of science. Many of these popular addresses, on a wide variety of subjects, were published. They included such titles as "Science, Materialism and Ethics," "The Contribution of Astronomy to Civilization," "The University and the Physical Sciences," "Scientific Imagination," "The Ethical Value of Science," "The Spectroscope, Key to Celestial and Atomic Mysteries," "The Evolution, Death and Resurrection of the Stars."

The geniality of Professor Lewis and his powers of conversation made him a welcomed addition to any intellectual gathering. He was an active member of several clubs, including the Chit Chat Club of San Francisco. He was a member of the American Physical Society, serving as a member of the council, as a member of the editorial board, and as Pacific

Coast secretary; the California Academy of Science; the Optical Society of America; the Astronomical Society of the Pacific, serving as a member of the board of directors and as president; the American Association for the Advancement of Science, serving as vice-president, physics section, and as president of the Pacific Division. He was a member of the honor societies Phi Beta Kappa and Sigma Xi.

Professor Lewis was married in 1901 to Louise Sheppard, of San Francisco. His widow, a daughter, Evelyn, and a son, John Sheppard, survive him. ELMER E. HALL

SCIENTIFIC EVENTS

THE BRITISH MOSQUITO CONTROL
INSTITUTE

Nature prints an account of the first statutory general meeting of the British Mosquito Control Institute, which was held at the Hotel Cecil, London, on March 30. The council was elected in accordance with the articles of association approved by the Board of Trade, and by which the institute is registered under the Companies Acts, 1908-1917, as a company limited by guarantee and not having a share capital. Since the anti-mosquito campaign was begun at Hayling Island about seven years ago, it has become increasingly evident that the work so successfully accomplished there is of more than local interest, and that medical officers of health and sanitary inspectors in many parts of Great Britain, as well as abroad, desire to know how to keep mosquitoes under control. The Ministry of Health can only concern itself with these insects as disease carriers, even though in some districts they make life out of doors almost intolerable in certain months of the year. The Natural History Museum is always willing to identify specimens and give general guidance on methods of dealing with them, but neither it nor the Ministry of Health is concerned with actual field operations by which the mosquito nuisance may be reduced or eliminated. This practical knowledge is, however, available at the British Mosquito Control Institute at Hayling, where there is now a substantial building with laboratory, museum, photographic room and other facilities for the study of all stages of mosquito life and its regulation. The institute has been vested in trustees by the founder and director, Mr. J. F. Marshall, whose devoted services in solving problems of mosquito control are widely known and appreciated. Membership is open to all who are interested in the subject, and it is hoped that, in due course, sufficient support will be forthcoming from members and public bodies to make the institute self-supporting and extend its activities. The council includes among its members

Sir Ronald Ross, Sir William Simpson, Sir Arthur Shipley, Dr. Andrew Balfour, Major E. E. Austen, Sir James Crichton-Browne, Dr. G. A. K. Marshall, Dr. C. M. Wenyon and other entomologists familiar with the mosquito pest, and the chairman is Sir Richard Gregory. The address of the institute is Hayling Island, Hampshire.

PUBLIC LECTURES AT THE SCHOOL OF TROPICAL MEDICINE OF THE UNI

VERSITY OF PORTO RICO

DURING the present (first) session of the school of tropical medicine of the University of Porto Rico and Columbia University, at San Juan, the following public lectures by visiting scientists were given:

January 11.

The environment: Professor E. B. Phelps, of the De Lamar Institute of Public Health, Columbia University.

February 4 and 9. Schistosomiasis, trypanosomiasis, and pulmonary distomatosis in Venezuela: Dr. Juan Iturbe, Caracas.

February 22 and 25. Bonds of union between tropical medicine and general medicine, and relationship between Weil's disease and yellow fever: Dr. A. W. Sellards, associate professor of tropical medicine, Harvard University.

March 2. Investigations on rickets in New Haven, Conn., and in Porto Rico, with special reference to the effects of sunlight: Dr. Martha Eliot, of the Children's Bureau, U. S. Department of Labor, and the Yale Medical School.

March 8. Experimental epidemiology: Dr. Simon Flexner, director of the Rockefeller Institute for Medical Research, New York.

The last lecture of the series was to be given on May 3 by Dr. James W. Jobling, professor of pathology in Columbia University, on "Blood Destruction with Special Reference to the Influence of Diet." R. A. LAMBERT,

Director

THE ONE THOUSANDTH MEETING OF THE ENTOMOLOGICAL SOCIETY OF CORNELL UNIVERSITY

ON May 28 there will occur an event of interest to many entomologists in this and in other countries: the one thousandth meeting of Jugatae, the entomological society of Cornell University. The society was founded on February 26, 1897, and has been an important factor in encouraging research in entomology at Cornell throughout its history.

The members of Jugatae are chiefly graduate students in entomology and members of the department. During the thirty years of its existence it has included students from all parts of the world, twenty-six countries having been represented at one time or another.

At present there are sixty active members representing Canada, Porto Rico, Chile, Hawaii, the Philippine Islands, Spain, Poland, Australia and China, as well as many of the states of our Union. A full list of prominent entomologists and biologists who have attended meetings would be much too long for presentation here but would include from our country Dr. L. O. Howard, Dr. W. M. Wheeler, Dr. S. A. Forbes, Dr. Herbert Osborn, Dr. Vernon Kellogg, and from other countries Dr. William Bateson, Dr. Paul Marchal, Dr. Arthur Gibson and Dr. I. J. Tillyard.

Own

Jugatae, though serving as a seminar for the entomological department, has become an institution at Cornell and has achieved a personality not often associated with a seminar. Its object has been "to give all members opportunity to learn of the advanced work being done in the department." Hence more time has been given "to reports of the results of original investigations than to compilations, summaries and reviews." Indeed, the programs of late years have consisted almost exclusively of reports on the research being done by members, and this, perhaps, is the chief reason for the intimacy of the meetings and the place the society holds in the conduct of the department.

The thousandth meeting is to be made the occasion for a celebration to which all its old members have been invited. This celebration will be held on Saturday, May 28, and it is hoped that of its hundreds of former members many will be able to attend.

THE AMERICAN PHILOSOPHICAL

SOCIETY

DR. F. X. DERCUм, emeritus professor of nervous and mental diseases at Jefferson Medical College, has been elected president of the American Philosophical Society to succeed the late Dr. Charles D. Walcott. Dr. Henry Fairfield Osborn, president of the American Museum of Natural History; Dr. William W. Campbell, president of the University of California, and Dr. James A. Breasted, professor of Egyptology and Oriental history at the University of Chicago, have been elected vice-presidents.

Dr. Arthur W. Goodspeed, of the University of Pennsylvania, and Dr. John A. Miller, of Swarthmore College, were named secretaries; Eli K. Price, of Philadelphia, treasurer, and William P. Wilson, of the Philadelphia Museums, curator.

The following councillors were elected to serve for three years: Dr. Edwin Grant Conklin, Princeton; Cyrus Adler and former Governor William C. Sproul, both of Philadelphia, and Charles F. Brush, Cleve land.

Fifteen new members were admitted-Roy Chap

man Andrews and Robert Henderson, New York; Arthur P. Davis, Oakland, Calif.; Joseph Erlanger, St. Louis; Irving Fisher and William Lyon Phelps, Yale University; Paul Darwin Foote and Gerrit S. Miller, Jr., U. S. Department of Agriculture, Washington; Tenney Frank, Baltimore; Frank Pierrepont Graves, Albany, N. Y.; B. Smith Hopkins, University of Illinois; Dr. Max L. Margolis, Dr. Thomas Lynch Montgomery, Dr. J. Parsons Schaeffer and Albert S. Weimer, Philadelphia.

ELECTIONS BY THE NATIONAL ACADEMY OF SCIENCES

Dr. Thomas Hunt MORGAN, professor of experimental zoology in Columbia University, was elected president of the National Academy of Sciences at the recent annual meeting held in Washington. Professor Morgan succeeds Professor Albert A. Michelson, of the University of Chicago, for a four-year term. The only other living past president of the academy is Dr. William H. Welch, of the Johns Hop

kins University. Dr. Frederick E. Wright, of the

Geophysical Laboratory of the Carnegie Institution of Washington, was elected vice-president, in succession to Dr. John C. Merriam, president of the Carnegie Institution. Dr. David White, of the U. S. Geological Survey, was reelected home secretary. As members of the council there were elected Dr. George E. Hale, Dr. John C. Merriam and Dr. J. McKeen Cattell. Members were elected as follows:

Eric Temple Bell, professor of mathematics, California Institute of Technology.

Charles Peter Berkey, professor of geology, Columbia University.

William Bowie, chief of the division of geodesy, U. S. Coast and Geodetic Survey.

Arthur Holly Compton, professor of physics, University of Chicago.

Benjamin Minge Duggar, botanist of the Missouri Botanical Gardens.

Thomas Alva Edison.

Rollins Adams Emerson, professor of plant breeding, Cornell University.

Herbert McLean Evans, professor of anatomy, University of California.

William King Gregory, curator of paleontology, the American Museum of Natural History.

Edwin Powell Hubble, astronomer, Mt. Wilson Observatory.

Claude Silbert Hudson, chemist, U. S. Bureau of Standards.

Alfred Newton Richards, professor of pharmacology, University of Pennsylvania.

Francis Peyton Rous, member of the Rockefeller Institute for Medical Research.

Albert Sauveur, professor of metallurgy, Harvard University.

Henry Van Peters Wilson, professor of zoology, University of North Carolina.

As foreign associates there were elected:

Paul Sabatier, professor of chemistry, University of Toulouse.

Godfrey Harold Hardy, Savillian professor of geometry, University of Oxford.

Carl Stumpf, emeritus professor of philosophy, University of Berlin.

At the meeting of the executive board of the National Research Council of the National Academy, the following general officers were elected: ChairEngineering Corporation, New York City; first viceman, Gano Dunn, president of the J. G. White chairman, T. H. Morgan, president-elect of the National Academy of Sciences; second vice-chairman, John C. Merriam, president of the Carnegie InMillikan, California Institute of Technology. The stitution of Washington; third vice-chairman, R. A. treasurer, Dr. George K. Burgess, director of the Bupermanent secretary, Dr. Vernon Kellogg, and the

reau of Standards, continue in these offices. To re

place vacancies occurring in the membership at large

of the executive board, James F. Norris, professor of

organic chemistry, Massachusetts Institute of Technology; F. R. Moulton, professor of astronomy, Uni

versity of Chicago, and John R. Freeman, consulting engineer, Providence, were elected.

SCIENTIFIC NOTES AND NEWS

DR. MAX WEBER, emeritus professor of zoology at the University of Amsterdam, an authority on marine mammals and fish and for many years engaged in oceanographic work, has been awarded the Agassiz Medal by the National Academy of Sciences.

DR. CHARLES S. Howe, president of the Case School of Applied Science, was awarded the Cleveland Medal for outstanding service in the public interest at the annual banquet of the Cleveland Chamber of Commerce held on April 19. Dr. Howe has been connected continuously with the school for the past thirty-eight years, taking the chair of mathematics and astronomy in 1899. In 1902 he succeeded Dr. Cady Staley as the second president.

DR. HIDEYO NOGUCHI, of the Rockefeller Institute for Medical Research, has been elected a member of the Royal Academy of Sciences of Denmark.

THE medical faculty of Freiburg University has conferred the distinction of doctor honoris causa on Tatsukichi Irisawa, professor of internal medicine at Tokyo.

AT a meeting of the Medical Society of London, held on March 28, the following were elected honorary

fellows: Professor Irving Cameron (Canada), Professor Sir Charles Sherrington (Oxford), Professor H. C. Jacobaeus (Stockholm), and Professor K. F. Wenckebach (Vienna).

DR. KONRAD E. BIRKHAUG, assistant professor of bacteriology in the University of Rochester School of Medicine and Dentistry, has been elected a member of the Norwegian Pathological Society in Oslo.

SIX American engineers have received the cross of knight of the Czechoslovak Order of the White Lion, "in appreciation of services rendered on behalf of the Czechoslovak State." They are Professor Joseph W. Roe, Calvin W. Rice, Alfred D. Flinn, H. S. Pearson, all of New York; Lawrence W. Wallace, of Washington, and Morris L. Cooke, of Philadelphia.

PROFESSOR CASSIUS J. KEYSER, of Columbia University, who asked to be retired on June 30, has been appointed Adrain emeritus professor of mathematics.

THE New York Academy of Dentistry recently gave a testimonial dinner to Professor William J. Gies, professor of biochemistry in Columbia University, in recognition of his completion of a survey of the status of dental education in this country on which he worked six years under the auspices of the Carnegie Foundation. At the dinner it was announced that a fellowship fund, to be known as the William J. Gies fellowship fund in biochemistry for dental students at Columbia University, has already received contributions amounting to $18,000.

DR. WILLIAMS MCKIM MARRIOTT, dean and professor of pediatrics of Washington University School of Medicine, St. Louis, has been elected temporary president of the newly organized Missouri Society for Crippled Children.

THE council of the British Illuminating Engineering Society has nominated D. R. Wilson as president for the coming session.

DR. F. L. PYMAN, professor of technological chemistry in the university and in the college of technology, Manchester, has been appointed head of the research laboratories of Messrs. Boots Pure Drug Company, Ltd.

PROFESSOR A. E. TAYLOR, director of the food research institute at Stanford University, has been appointed by President Coolidge a member of the American delegation to the International Economic Conference called by the League of Nations to meet in Geneva on May 4.

DR. J. C. DRUMMOND, professor of biological chemistry at University College, London, and Dr. E. K. Rideal, lecturer in physical chemistry at the University of Cambridge, are among those who have ac

cepted invitations to take part in the program of the Institute of Chemistry of the American Chemical Society to be held this summer at Pennsylvania State College.

RECENT foreign visitors to the United States include Dr. G. Delepine, professor of geology at Lille, France; C. M. F. Swynnerton, chief of the department of game preservation, Tanganyika Territory, Africa, and T. H. C. Taylor, an entomologist on the staff of the Department of Agriculture, Fiji.

Nature states that Sir John Russell, director of the Rothamsted Experimental Station; Major Walter Elliot, Parliamentary Under-Secretary of State for Scotland and chairman of the research committee of

the Empire Marketing Board, and Dr. J. B. Orr, director of the Rowett Institute for Research in Animal Nutrition, Aberdeen, are on their way to Palestine to inquire into problems of animal husbandry. The delegation will meet delegates from Cyprus and probably also from Iraq.

L. W. KEPHART, agronomist in clover investigations, office of forage crops, and R. L. Piemeisel, physiologist of the office of plant geography and physiology, U. S. Bureau of Plant Industry, left Washington on May 1 on a ten-month collecting trip into British East Africa.

HENRY B. COLLINS, JR., and T. Dale Stewart, of the U. S. National Museum, have left Washington for Alaska to seek for the remains of ancient man and to study contemporary races.

UNDER the direction of Dr. Max S. Dunn, assistant professor of biochemistry of the University of California, the whaling ship Lansing has been cruising off the coast of southern California and Mexico in search of whales, from which the pituitary and some other glands are being preserved for study in laboratories of the university.

DR. FRANCIS M. ROOT, associate in medical entomology at the School of Hygiene of the Johns Hopkins University, sailed on April 27 for Venezuela, where he will study the mosquito of the region. He expects to be away until September.

DR. WALTER T. SWINGLE, in charge of the office of crop physiology and breeding, U. S. Bureau of Plant Industry, sailed for Algeria on April 9, to attend a conference called to discuss baiudh, a destructive disease of dates.

DR. LECOMTE DU NOUY, associate member of the Rockefeller Institute for Medical Research, is going to Paris in June on a year's leave. He will continue the work which he has been carrying on on the sur