The University of Michigan, an encyclopedic survey ... Wilfred B. Shaw, editor.

THE DEPARTMENT OF PHYSICS

The subject of physics was first taught in the University in the autumn of 1843, under the name of natural philosophy. Some eleven juniors constituted the first class, and the instruction was conducted by George Palmer Williams (Vermont '25, LL.D. Kenyon '49), who also taught mathematics under the title of Professor of Natural Philosophy and Mathematics. From this modest beginning there has been a continuous evolution into the present Department of Physics, comprising in the various ramifications of its activities a staff of some sixty men, including assistants and technicians, and occupying two large buildings.

In Detroit, first as the "Catholepistemiad, or University of Michigania" in 1817, then as the University of Michigan in 1821, the institution had been unable to find sufficient students of collegiate grade. It had therefore confined itself largely to secondary instruction, and for a time continued to do so even when, on Michigan's admission to statehood in 1837, the Board of Regents was established and the site at Ann Arbor was determined upon. Regular university instruction began in Ann Arbor only in 1841. At the same time the Regents withdrew a large part of the support which they had been pouring into the several University-sponsored and University-controlled secondary schools about the state, called branches (see Part I: Early History and Branches ).

In anticipation of the opening of the central institution, the Regents, in July, 1841, appointed George P. Williams to be Professor of Languages; but in August, upon his own request, they made him Professor of Mathematics instead, and appointed the Reverend Joseph Whiting to the professorship of languages. Both took up residence in Ann Arbor in September, and, announcement having been previously made that college instruction would begin, seven students presented themselves. Only freshman and sophomore classes were organized the first year; the sophomore class consisted of one student, who was later absent for one year, but returned

and graduated with the class below in 1845. The subjects of instruction consisted of mathematics and the ancient languages and literature. Professors Williams and Whiting constituted the entire resident staff.

During the next academic year, 1842-43, the same subjects of instruction were continued for the original class, now sophomores, with a brief course in logic perhaps added. Some additional students joined this class from time to time, and a new freshman class had entered.

In the third and fourth years of the curriculum the study of the ancient languages was much reduced and natural philosophy, astronomy, chemistry, zoology, geology, and some of the social sciences were studied. The academic year was at first, and until 1856-57, divided into three terms.

By the autumn of 1843, according to the Catalogue, Williams' title had been changed to Professor of Natural Philosophy and Mathematics, and, as previously stated, he conducted the instruction of the first class in natural philosophy, consisting of junior students; the instruction was given in the first and second terms of the third year of the curriculum.

The textbook was the two-volume Introduction to Natural Philosophy by Denison Olmsted, professor of natural philosophy and astronomy in Yale College. This was first published in 1832. In 1837 the same author published also a more elementary text in one small volume, for "schools and academies." A copy of the elementary text is at hand, but the college text in its two-volume form is not available. After several revisions, however, the college text was stereotyped in 1844 and was thereafter issued in a single octavo volume of nearly six hundred pages, as occasion demanded. In an 1858 reprint of this text, which is at hand, mechanics, acoustics, electricity, magnetism, and optics are treated.

The text is on the whole thorough and excellent, but under electricity, to which seventy pages are devoted, not a word is said on the subject of electric currents, for the reason that "in Yale College, Galvanism and its kindred subjects are assigned to the chemical department." Thus Ohm's law, which had been announced in 1826, is not mentioned; moreover, under magnetism nothing is said concerning Oersted's epoch-making discovery made in 1820, of the effect of the electric current on the magnetic needle, nor of the equally momentous discoveries made some twelve years later by Faraday and by Joseph Henry of the phenomena of electromagnetic induction and of self-induction.

This is strange, especially in view of the fact that Joseph Henry's work was carried on first at Albany and then at Princeton, two cities both rather near New Haven. Were the Yale chemists appropriating all of these marvelous advances in physics of the time, or were these great discoveries as yet too little understood to permit of treatment in a college text? In the part of the book which is devoted to optics, the phenomenon of polarization by reflection, discovered by Malus in 1808, is adequately treated, as is also Fraunhofer's discovery of the dark lines of the solar spectrum, announced in 1817. But Young's development of the principle of interference, 1801-4, is accorded only a few sentences (with no mention of Young's name), and Fresnel's great researches of the years 1815-24 are ignored (though Fresnel is incidentally mentioned in a footnote).

In the early years at Ann Arbor, as elsewhere at the time, instruction was almost entirely from textbooks. Recitation of subjects assigned for study consumed the greater part of the class periods, combined, of course, with discussion. Lectures

were only occasional, and there were no demonstration lectures, which we now hold as important in the experimental sciences. Moreover, the student was offered no opportunity whatever to carry out experiments for himself. Laboratory instruction in physics at the University lay as yet nearly forty years in the future.

During the decade 1843-53 the instruction in physics was conducted in the manner just outlined.

Williams, as senior member of the faculty, and through his genial spirit coupled with an alert mind and kindly humor, held a unique place in the University during its first forty years at Ann Arbor. A multitude of students came to him for counsel, and all loved him. To them he was affectionately known as "Punky." But, though revered, he did not escape the crude pranks occasionally played by the students in the early days. It is recorded that early one morning the students led a donkey into his classroom, and tied it behind his desk. When he entered, the students were all in their seats. He bowed and said, "Good morning, gentlemen! I see you have no need of me this morning, having already provided yourselves with an instructor fully qualified to instruct you," and thereupon he walked out.

While Professor Williams was now by career a mathematician and natural philosopher, he maintained his interest in languages and in theology, in both of which he was proficient. Throughout his life he was deeply religious and had had and retained a desire to be some day ordained a minister. Once he had been accepted for ordination, but he then refused because of doubts in regard to his own worthiness. At length he was ordained, in 1846, as a minister of the Protestant Episcopal church and subsequently, while retaining his duties at the University, served for about two years as rector of Saint Andrew's Church of Ann Arbor, without salary, in order to help this church out of financial difficulties.

President Tappan, who entered upon his duties in the autumn of 1852, at once wisely stressed the need for augmentation of the faculty. Inasmuch as Williams had become overburdened in his dual professorship of mathematics and natural philosophy, and since a need for an engineering course had developed, Tappan urged the appointment of a professor of physics and civil engineering. The Regents created the proposed professorship and selected a man recommended by the Reverend Erastus Haven, then Professor of Latin in the University and later its President, as well as by the famous botanist Louis Agassiz and others, as an individual of superior and versatile attainments, qualified to hold a professorship in almost any branch of science.

The man in question was Alexander Winchell (Wesleyan '47, LL.D. ibid. '67). He was called in the autumn of 1853, but was delayed until January, 1854, in Alabama, where he had been teaching, by an outbreak of yellow fever. Immediately after his arrival Winchell entered upon his new duties, and by the autumn of 1854 the title and functions of George P. Williams had been limited to those of a professor of mathematics, as Winchell was filling the professorship of physics and civil engineering. It devolved upon Winchell, moreover, to select and purchase the first physical apparatus for the University, an initial appropriation of $500 having been made for this purpose.

Unfortunately, Winchell soon fell into disfavor with President Tappan. Probably the chief source of their discord was personal incompatibility, but in any event Tappan felt that Winchell had been inattentive to his duties, and, after a year, effective in the autumn of 1855, had him transferred to what he considered

a less important chair. Another factor in the situation may have been that Winchell's dominant interests were in fields other than physics and engineering. He subsequently had a distinguished career, principally as a geologist.

Simultaneously with the transfer of Alexander Winchell, Lieutenant William Guy Peck (U.S. Mil. Acad. '44, A.M. Trinity [Conn.] '53, LL.D. ibid. '63) was called to the chair of physics and civil engineering. Graduated first in his class at West Point, he had served in the Mexican War and then as an assistant professor of mathematics at West Point. He filled his professorship in Ann Arbor for two years, 1855-57, and then was called to Columbia University.

During the period of Peck's incumbency of the chair of physics the first Chemical Laboratory Building was erected. It was a small building which, after numerous and extensive enlargements, is now known as the Economics and Pharmacology Building. The facilities thus provided for laboratory work in chemistry were among the best of the day in America. At this University as well as elsewhere, chemistry was the science which first introduced laboratory instruction.

No provision had been made in the late summer of 1857 for the courses in physics and engineering for the coming year. At that time a recent graduate of the Rensselaer Polytechnic Institute stopped over in Ann Arbor, to visit the University, on his way to Chicago, where he intended to seek employment. He called upon President Tappan, and in the ensuing conversation Dr. Tappan suggested that the young man, DeVolson Wood by name, remain in Ann Arbor and for the time being undertake the instruction in the courses in question, with the understanding that he would have to content himself with such remuneration for this service as the Regents might deem proper to allot to him. Wood accepted. He proved himself capable and was soon given an appointment as an assistant professor, which he held for two years. In June, 1859, he was made Professor of Physics and Civil Engineering, but he held this title for only one year.

The time was ripe for the creation of a separate professorship of engineering, and DeVolson Wood (C.E. Rensselaer Polytechnic Inst. '57, M.S. Michigan '59) was chosen for this chair. In 1860 James Craig Watson ('57, Ph.D. Leipzig '70), who had for a year been Professor of Astronomy, was appointed to the professorship of physics, which he held for the three years 1860-63. Williams then became Professor of Physics and retained this appointment until his retirement in 1875.

In 1871 George Benjamin Merriman (Ohio Wesleyan '63, A.M. Michigan '64) was transferred from an assistant professorship of mathematics to an adjunct professorship of physics. Williams was aging and needed relief from the burden of his post. In view of his long and conspicuous service, however, he was continued in the rank and with the salary of professor of physics, but without duties.

Merriman was the first native son of the state to have charge of or take part in the instruction of physics at the University. He was born at Pontiac on April 13, 1834.

The lecture rooms and chapel of University Hall were ready for occupancy in October, 1872 (the auditorium not until a year later), and the situs of the instruction in physics was now transferred to this new building; space was allotted in the southeast corner of the fourth floor. Just previous to this removal the classes in physics had been held in the North College (Mason Hall). In the very early years, when this was the only college building, the instruction in all branches of learning had been given there. Upon

completion of the South College (South Wing) in 1848, the classes in some subjects were transferred to it. Rather more likely than not, physics remained in the North College until removed to University Hall. A fact which bears upon this question but yet furnishes no definite clue is that the above-related donkey episode, which occurred in 1857, was reported concurrently in the Detroit Free Press as having taken place in the North College. But this episode occurred while Williams was Professor of Mathematics only. Mr. Levi Wines, an alumnus of keen intellect who entered the University in the autumn of 1870, stated that he, as a prospective freshman, went to interview Williams, at that time again Professor of Physics, and that Williams' office and classroom were then in the North College. Accordingly, the instruction in physics was either still or again being given in the North College. Mr. Wines could not recall with certainty just where within the North College Williams' rooms were situated, but he was inclined to believe that they were in the southeast corner of the second floor.

Mr. Wines also said that when he attended the course in physics, probably in 1872-73 and in any event during the years that it was conducted by Professor Merriman in University Hall, the course included lectures as well as recitations, and the lectures were accompanied by ample demonstrations. The students, however, were given no opportunity to perform experiments themselves. Also, the well-known Ganot's Physics was then being used as a text. This continued to be used for many years.

At this period the students annually celebrated at the conclusion of the course the "burning of physics" or the "burning of mechanics," which was a comic ceremony in which an effigy representing physics or mechanics was by way of climax to appropriate obsequies cast upon a burning pyre. This custom originated in 1860 and was continued with perhaps an occasional omission until 1881. The class of 1875, moreover, feeling that the "burning of physics" was not enough, arranged in addition an entertainment in Hangsterfer's Hall in downtown Ann Arbor, of which the principal attraction was a parody on a demonstration lecture in physics — featuring experiments which didn't work!

In June, 1875, Merriman terminated his service at the University to accept the professorship of mathematics at Albion College. In the interim the alumni had generously raised a liberal pension fund for Professor Williams (see Part II: Alumni Association) , and he was at this same time definitely retired with the title of Emeritus Professor of Physics. He continued to reside in Ann Arbor until his death on September 4, 1881, at the age of seventy-nine years.

John Williams Langley (Harvard '61, M.D. hon. Michigan '77, Ph.D. hon. ibid. '92), a brother of the famous Samuel Pierpont Langley, replaced him. A graduate of the Lawrence Scientific School of Harvard, Langley had studied medicine for a year at Michigan, and had been in succession an acting assistant surgeon in the United States Navy, an assistant professor of natural philosophy at the Naval Academy, and a professor of chemistry at the Western University of Pennsylvania. He conducted the instruction in physics here for two years in conjunction with work in chemistry, under the titles of Acting Professor of General Chemistry and Physics for the year 1875-76 and Professor of the same subjects during 1876-77. Thereafter, he was Professor of General Chemistry only.

In the autumn of 1877 Charles Kasson Wead (Vermont '71, A.M. ibid. '74) assumed the work in physics under the title of Acting Professor of Physics. He had done graduate study in this country, and

this was followed by three years of teaching and a year of study in Berlin. Under C. S. Wead the first instructional laboratory in physics was inaugurated in February, 1878; it extended along the east side of the fourth floor of University Hall. Wead's field of principal interest was acoustics. He remained at the University until 1885 and then, or soon after, returned to the East. After a period of some years he entered the United States Patent Office.

During the year 1885-86 the professorship of physics was vacant. To provide instruction in the interim, however, Mark Walrod Harrington ('68, A.M. '71, LL.D. '94), Professor of Astronomy and Director of the Observatory, assumed temporary charge of the courses in physics, and DeWitt Bristol Brace was Assistant Professor of Physics from February until June. The latter subsequently became a professor of physics at the University of Nebraska.

Henry Smith Carhart (Wesleyan '69, Sc.D. Northwestern '12, LL.D. Michigan '12) assumed his duties in the fall of 1886 with the title of Professor of Physics and remained at Michigan in that capacity until 1909. He came from Northwestern University, where he had been for fourteen years. Born at Coeymans, New York, on March 27, 1844, he had obtained his bachelor's degree at Wesleyan University, Middletown, Connecticut, and had then studied at Yale for a year before going to Northwestern.

When Carhart arrived the time was ripe for the erection of a laboratory building for physics and hygiene. Construction was begun in 1887, and the building was ready for occupancy in the autumn of 1888. The original Physics Building was considerably enlarged on its west side in 1905, the added part including the room known as the West Lecture Room. The structure is now called the West Physics Building.

With the facilities provided by the completion of the Physics Building in 1888 the functional activities in the field of physics at the University began a rapid advance in status and expansion in scope. Playing equally important roles in bringing about this advance and expansion were two additional factors. First, the University as a whole was growing and maturing rapidly, and second, a great developmental influence was exerted personally by Carhart, through his energy and ability as a scientific investigator. He was internationally known for his contributions to the progress in electricity which was being made in his day. In 1890 the additional title of Director of the Physical Laboratory was conferred upon Carhart.

During the decade 1890-1900 several appointments were made in physics in the ranks of instructor, assistant professor, and junior professor, with advance in rank of the incumbents from time to time. There thus evolved during this decade what may properly be called a staff in physics and a Department of Physics. Those holding appointment continued in the department into the new century.

The six men conducting the instruction in physics in 1901-2 included two recent additions and were as follows: Henry Smith Carhart, Professor of Physics and Director of the Physical Laboratory; John Oren Reed ('85, Ph.D. Jena '97), Junior Professor of Physics; Karl Eugen Guthe (Ph.D. Marburg '89), Assistant Professor of Physics; Harrison McAllister Randall ('93, Ph.D. '02), Instructor in Physics; George W. Patterson, Junior Professor of Electrical Engineering; and Benjamin F. Bailey, Instructor in Electrical Engineering. Of these six, it is rather remarkable that all have been, or are at present, heads of departments in the University, and three have been deans. Carhart was succeeded

as Director of the Physical Laboratory by Reed, Guthe, and Randall, in the order named. Randall continued as Director until his retirement in 1941, when Ernest Franklin Barker (Rochester '08, Ph.D. Michigan '15) was made Chairman of the Department of Physics. Patterson became the head of the Department of Electrical Engineering in 1905 and continued in that capacity until 1915. He was also head of the Department of Engineering Mechanics from 1914 until his death in 1930. Bailey became the head of the Department of Electrical Engineering in 1922, and holds that position at the present time (1942). The three who became deans were John O. Reed, who was the first Dean of the Summer Session and later was Dean of the Literary Department, Karl E. Guthe, who was chosen the Dean of the Graduate School upon its reorganization in 1912, and George W. Patterson, who was Assistant Dean of the Engineering College from 1922 to 1927, Acting Dean for the year 1927-28, and Associate Dean 1928-30. Dean Patterson died May 22, 1930. For many years he conducted the more advanced courses in electricity in the Department of Physics, even after his title became Professor of Electrical Engineering. He was joint author with Professor Carhart of a textbook, Electrical Measurements, which was in use for a number of years. Perhaps one of the most popular high-school texts on physics was one known as Carhart and Chute, from the names of the authors. The second author was Horatio Nelson Chute ('72, A.M. '75, LL.D. Denison '09), of the Ann Arbor High School. Carhart's Physics for University Students was also used as a text in the courses in general physics, especially by engineering classes. His most important contributions to physics were on electrical and electrochemical subjects. He established courses in electrochemistry in the physics curriculum, and was an authority on standard cells. He was made Professor Emeritus in 1909 and died in 1920. Most of his years after retirement were spent in California.

Professor Reed is remembered by all his students as a very vigorous and efficient teacher, who had little patience with sham and nonsense, but who labored with boundless energy to aid those who proved themselves capable and eager to learn. His interest was principally in the subjects of sound and light, and he prepared excellent laboratory courses in those branches. In March, 1912, he obtained a leave of absence because of illness. He died January 23, 1916.

Karl E. Guthe, after having been a member of the Department of Physics for some years, resigned and engaged in research at the Bureau of Standards from 1903 to 1909, then returned as Professor, and later succeeded John O. Reed as Director of the Physical Laboratory. Together with Reed he published College Physics, a text which enjoyed wide use in courses in general physics. Guthe's reputation for scholarship and research made him the choice for the first Dean of the Graduate School. Unfortunately, his inspiration and services in this capacity were cut short by his sudden death in Oregon, September 10, 1915.

The death of Professor Guthe occurred so near the opening of the school year that there was practically no time left for his successor to make plans to carry the load thus suddenly thrust upon him. Upon H. M. Randall devolved the responsibility of directing the affairs of the department and of providing for the needs of graduate students, who were coming in increasing numbers. How well he assumed these duties is indicated by the enormous increase of the research facilities and activities of the department under his directorship, by the large number of students pursuing advanced work, and by the expansion of the teaching

curriculum to include instruction in the most modern and advanced aspects of physics. Randall is a joint author, with N. H. Williams and W. F. Colby, of General College Physics, a text which is used at present in the general physics classes of the University. His major research interest is in radiation, particularly that of the infrared region of the spectrum. To this field he has made fundamental contributions, important not only for the information they yield, but even more because of the extensive developments that have followed, in which similar methods have been utilized. His own investigations and those of his associates have brought to the laboratory high distinction, and established it as a leading center for infrared research. Randall in 1937 was president of the American Physical Society.

The courses of instruction. — Until about 1880 it could scarcely be said that anything beyond elementary physics was offered in the courses of instruction. Under C. K. Wead, however, more work in optics, acoustics, and electrical measurements was initiated. Commercial applications of electricity had been developing rapidly, and soon after Carhart took charge in 1886 new courses began to appear. Thus, in 1888 was instituted a course in dynamoelectric machinery, and in 1889 there were courses in mathematical electricity, in electric batteries, and in the photometry of electric lamps. In 1891-92 were added the study of transformers, more laboratory work in electricity, and the theory of light. A course in the theory of heat was first offered in 1893-94, and advanced studies in sound and light in 1895-96. The courses in sound and light were taught by John O. Reed; those in electricity were given by Carhart and Patterson.

In the year 1900-1901 a colloquium was added, for which one hour of credit was given each semester. In this colloquium advanced students joined with the teaching staff in presenting reports on research and on other topics of interest.

Although the courses in general physics have been modified from time to time to meet the needs of those preparing for the different professional schools, it may be said that since 1887 a full year's course of at least five class or laboratory periods per week has been given. At present the students preparing for medicine, dentistry, and pharmacy take the same course in physics as those in the College of Literature, Science, and the Arts. Of engineering students an additional amount of work in the solution of problems is required.

The subject of thermodynamics had been well developed for many years previously, but there was not sufficient demand for advanced study in this subject until the year 1901-2, when Karl E. Guthe first offered a course under this name. A course in electrochemistry was introduced by Carhart in 1902-3, and one entitled Advanced Electricity and Magnetism by Patterson in 1904-5. In 1907-8 instruction in the measurement of high temperatures was begun by Randall. Two courses in advanced physics were given by Guthe, beginning in 1910-11. These have since given way to separate intermediate courses in mechanics, sound, heat, and light. In the same year were announced a seminar and courses on electromagnetic theory by Guthe, on direct and alternating currents by Neil Hooker Williams (93e, Ph.D. '12), and on radiation by Randall. For ten years following Carhart's resignation the laboratory course in electrochemistry was carried on by William D. Henderson ('03, Ph.D. '06), who later became Director of the University Extension Service.

Courses in German and French reading for students of the sciences were first listed in the physics group in 1912-13. A course in X rays was first offered by

David Locke Webster (Harvard '10, Ph.D. ibid. '13) in 1917-18, and one on the theory of gases by Walter Francis Colby ('01, Ph.D. '09) in 1920-21. Work in modern physics was introduced by Colby in 1921-22, as was also the study of vacuum tubes by Williams. In 1923-24 appeared announcements of courses in quantum mechanics by Colby, on physical optics by William Warner Sleator ('09, Ph.D. '17), and on atomic structure by Ernest Franklin Barker; in 1924-25, geometrical optics by Ralph Alanson Sawyer (Dartmouth '15, Ph.D. Chicago '19), theoretical mechanics by Oskar B. Klein (Fil.Dr., Inst. for teor. Fysik [Copenhagen] '21), spectral series by Randall, X-ray equipment and apparatus by George Allan Lindsay ('05, Ph.D. '13), and electronics and conduction of electricity through gases by Ora Stanley Duffendack (Chicago '17, Ph.D. Princeton '22); in 1925-26, laboratory work in radioactivity by Arthur Whitmore Smith (Dartmouth '93, Ph.D. Johns Hopkins '03); in 1926-27, high-frequency measurements by Williams, architectural acoustics by Daniel Leslie Rich (Waynesburg '02, Ph.D. Michigan '15), and theory of spectra by Otto Laporte (Ph.D. Munich '24); in 1927-28, quantum mechanics by Laporte, theory of band spectra by David Mathias Dennison (Swarthmore '21, Ph.D. Michigan '24), infrared radiation by Randall, and contemporary physics by George Eugène Uhlenbeck (Ph.D. Leiden '27); in 1928-29 a proseminar for the master's degree and a year's work in molecular physics for graduate students not specializing in physics, and quantum theory and atomic structure by Dennison. In 1929-30 the theory of atomic spectra was introduced by Samuel Abraham Goudsmit (Ph.D. Leiden '27), and some eleven courses of special investigation were provided for graduate students with the idea of offering preliminary investigation in any line to those not quite ready to begin a subject for the doctor's degree. In 1934-35 a non-technical course in general physics was introduced by Rich especially for students not intending to continue work in physics; in 1937, mechanics of fluids by Lindsay; in 1939, nuclear physics by Horace Richard Crane (California Inst. Technol. '30, Ph.D. ibid. '34); and in 1942, introduction to aerodynamics by Uhlenbeck. Since 1920 Charles Ferdinand Meyer (Johns Hopkins '06, Ph.D. ibid. '12) has had charge of the laboratory in physical optics.

The average numbers of courses listed each year during five-year intervals are given in Table I.

TABLE I

Interval	Number of Courses Offered
1901-6	23
1906-11	25
1911-16	34
1916-21	38
1921-26	40
1926-31	51
1931-36	64
1936-41	48

Nearly all of the courses which are now considered as advanced work for graduate students have been added since 1920. Among the few exceptions to this are courses in electricity and magnetism and in thermodynamics.

The inclusion of new courses in the curriculum follows rather closely the advance of research in any particular phase of the subject. For example, the great activity in research concerning the structure of the atom in the years about 1920 corresponds with the introduction of a course in atomic structure in 1923, and the development of new types of vacuum tubes and their application to radio communication were followed by a course in vacuum tubes in 1921. In general, there has been a great increase in

the amount of theoretical physics offered since 1920. The same period has witnessed a remarkable growth in the research productivity of the department. This growth was unquestionably favored by the unusual conditions in physics during these years, for so many new experimental results were obtained through such agencies as optical and X-ray spectra — in fact, through measurements of electromagnetic radiation, from the greatest wave length down to cosmic radiation at the other extreme of the spectrum — that there was almost unparalleled opportunity for new investigation. The policy of Karl E. Guthe, Director of the Physical Laboratory from 1911 until 1915, and of H. M. Randall since that time, was definitely to encourage research to the fullest extent. This encouragement by word, by example, and by every effort to provide the necessary apparatus for the problems undertaken has been a source of continual inspiration to the members of the staff. Fortunately, the new building (East Physics Building), erected in 1924, afforded more space and other facilities without which many of the investigations since successfully carried on would have been quite impossible. In this new structure, renamed the Harrison M. Randall Laboratory of Physics in 1940, are conducted the advanced classes as well as the research work. The offices of the permanent members of the staff are also located there. The elementary class and laboratory work is carried on in the older West Physics Building.

The number of graduate students in physics has increased rather steadily, and the increase has been rapid since 1925. Because of the different manner of publishing registers of students in different years, it is difficult to obtain complete and reliable figures on the total number specializing in the department for all the years. In Table II, which has been compiled from various tabulations, the net numbers of graduate students specializing in physics are given for every fifth year. Previous to 1890 the subject of specialization was not recorded in the registers. The record of the master's and doctor's degrees begins with 1891.

Laboratories. — Although the teaching of physics began in 1843, laboratory work was not started until the beginning of the second semester, February 18, 1878. The space then devoted exclusively

TABLE II

Year	Number of Graduate Students Specializing in Physics	Master's Degrees Granted	Doctor's Degrees Granted
1890-91	1	..	..
1895-96	4	2	..
1900-1901	6	2	..
1905-6	15	5	1
1910-11	28	2	1
1915-16	23	2	2
1920-21	27	7	..
1925-26	57	10	7
1930-31	118	15	7
1935-36	100	20	5
1940-41	101	21	8

to the Department of Physics extended, as stated in the catalogues of the time, "in a direct line over 125 feet," was "well lighted from the north, east, and south," and "was provided with gas, steam, and water." This laboratory was in a suite of rooms on the top floor of University Hall adjacent to the office occupied by Professor C. K. Wead, who was then in charge of the instruction in physics.

A new $30,000 physics laboratory, the first unit of what is now known as the West Physics Laboratory, was ready for

occupancy in October, 1888. The basement and the second story were occupied by physics and the third story by the laboratory of hygiene. On the completion of the then "new" Medical Building in 1903, the laboratory of hygiene was removed to new quarters, thus leaving much needed room for the development of physics (see VIII: West Physics Building) .

In 1905 an addition, costing, with equipment, about $45,000, was made. An important feature of this addition was a well-equipped lecture room (the West Lecture Room) accommodating four hundred students. The entire building is still used exclusively by the department. It houses a well-equipped shop employing five full-time instrument makers, a liquid-air plant with a capacity of four quarts per hour, a glass-blowing room in which two professional glass blowers work, a large lecture room, six apparatus rooms, a battery room, eight rooms for elementary laboratory work, six classrooms, and a few offices.

In 1920, two large rooms at the north end of the basement in Tappan Hall were taken over. One was used for spectrographic research, and the other served as a light laboratory. These continued to be occupied as physics laboratories for four years.

During 1923 and 1924 a new building, standing in part on the site occupied from 1850 to 1913 by the first Medical Building, was erected. This new structure, the East Physics Building, cost, exclusive of equipment, about $450,000 and was ready for occupancy in February, 1924. It is an L-shaped building, the outside of the L being 144 feet by 132 feet and the wings 60 feet wide. There are four floors above ground, and a full-lighted basement; under about three-fourths of this basement is a subbasement, and under one-half of this subbasement is a subsubbasement, making the building, in part, seven stories high. The soil on which the structure stands is good building gravel to a depth of about 300 feet, and the water table is about 80 feet below the surface. This very favorable soil condition makes the lower basements not only dry but also exceptionally free from vibration. These lower rooms, well ventilated, well lighted artificially, and easily kept at a uniform temperature, have proved to be the rooms most in demand for research (see Part VIII: Randall Laboratory of Physics) .

The building is of the skeleton-type construction, the reinforced concrete columns and floor slabs carrying the entire weight and providing almost the entire strength of the structure. This type of construction permits the interior walls and partitions to be of light, easily removable hollow tile. The floors were finished before these light partitions were erected, and the partitions themselves have been kept almost entirely free from permanent wiring and piping. The result is that rooms may easily be made larger or smaller by the removal or by the insertion of a wall. Experience has proven this type of construction to be a very wise one; in spite of careful planning, many changes in the locations of partitions have been found desirable. The skeleton columns were so spaced as to make the natural unit of construction twelve by twenty-four feet; that is, nearly all rooms are either of this size or of a small integral multiple of this size. A two-unit room is twenty-four feet square, a three-unit room, a third larger on one side.

Probably the most elaborate single item in the building is the electrical wiring. In addition to 110- and 220-volt D.C. and 110- and 220-volt three-phase A.C., the laboratory has three battery rooms and several motor generators. Each unit room, in addition to ordinary lighting and power service, is provided

with circuits which permit any of the available sources to be used. On the average about six individual circuits for experimental purposes are available in each unit room. The interconnecting of this electrical system requires over thirty separate plug- and switch-boards ranging in size from six square feet to eighty square feet each, and literally thousands of circuits. The electricians who wired the building made the remark that reinforcing steel might have been dispensed with, the concrete being sufficiently strengthened with electrical conduits.

Several other unusual features were incorporated, which permit flexibility and expansion of the various services supplying electricity, water, gas, steam, and compressed air; also special wood mounting strips and hundreds of threaded inserts were imbedded in the concrete walls and ceilings, to provide facilities for the rigid attachment of apparatus.

A four-unit, two-story room was provided for high-voltage research; also a separate two-story building on its own separate and very special foundation was provided, within the main building, for work in sound. This sound building contains two soundproof rooms and a large reverberation room, adjacent to other rooms planned for observation in sound. This sound building, a relatively heavy structure, is the most nearly free from vibration of any place in the Randall Laboratory. The lower walls and floors of the main building, because of the nature of the gravelly soil in which the building stands, are also nearly vibrationless; but, contrary to expectation, the special piers in the openings of the lowest basement floor are not so free from vibration as are the lower basement walls.

The East Physics Building is used mainly for advanced work. About 55 per cent of it is given over wholly to research. Advanced instructional laboratories occupy an additional 25 per cent, and the remaining 20 per cent is taken up by offices, a library, and three classrooms. The elementary work has remained in the old West Physics Building.

According to present plans the East Physics Building will at some future time be extended toward the west and north and will thus, in conjunction with the structure now existing, form a U. Within this U would be two large lecture rooms, and north of these would be an instrument shop. Accordingly, the ground area which is occupied by the present building is less than one-half the area which the contemplated complete structure will occupy. With the realization of this development the West Physics Building would no longer be needed.

Research. — The extent of the contributions to the science of physics from the University of Michigan is indicated by a long list of papers and reports, some five hundred in all, originally published in various journals, but now available in collected form. They appear in the following two series:

• University of Michigan Physical Laboratories, Papers. 1879-1910, 6 volumes.
• Contributions from the Physical Laboratory of the University of Michigan. 1911-41, 6 volumes.

Some of these papers are concerned with problems in the teaching of physics, but the great majority deal with fundamental principles, either presenting significant experimental results, or discussing their interpretation, or both. A very few may be assigned to the category of applied physics, since they aim primarily at the utilization of scientific information rather than at the extension of knowledge. The relatively small proportion of such "practical" studies does not by any means signify that research in physics is of little value to the community, nor that the specialists in this field are insensitive

to the needs which their science might supply. It is, in fact, the result of a somewhat artificial classification which tends to transfer to the realm of engineering any development the aim of which is primarily utilitarian. A case in point is provided by the history of the dynamoelectric machinery laboratory. The principle of electromagnetic induction was discovered almost simultaneously by Joseph Henry and by Michael Faraday in the year 1831, but it remained a matter of "academic" interest until 1876, when the first practical generator was built. This machine was exhibited at the Centennial Exhibition in Philadelphia by its inventor, Mr. Charles Brush of Cleveland, a former Michigan student. For the first time in history it made possible the operation of an arc lamp without batteries. Professor Langley, after seeing the demonstration, returned to the laboratory here and constructed a dynamo of similar design but with some improvements and a larger output, so that three arc lamps could be operated at once. This early machine is still in the possession of the University. It constituted the beginning of a laboratory of dynamoelectric machinery, organized at first in the Department of Physics and later developed into the extensive laboratories of the Department of Electrical Engineering.

That type of research which aims at a more nearly complete understanding of natural laws, without concern for utilitarian or commercial values, is often called pure science. Investigations of this sort dealing with a very great variety of subjects have been included in the research program of the physics laboratory. Most of them may be listed in a rough classification (Table III).

By the end of the nineteenth century the so-called classical physics had assumed a fairly complete and consistent form, the last major developments having been in the field of electricity and magnetism. In 1889 Henry S. Carhart wrote in his vice-presidential address before the American Association for the Advancement of Science:

Even popular interest in electricity is now well-nigh universal. Its applications increase with such prodigious rapidity that only experts can keep pace with them. At the same time the developments in pure electrical theory are such as to astound the intelligent layman and to inflame the imagination of the most profound philosopher.

Carhart was himself a profound scholar in this field, and his own researches, together with those of his associates, contributed greatly to its development. Of particular note was his series of studies (1899; 1903) on primary cells, revealing

TABLE III

	Published Reports
Mechanics, optics, sound, and heat	70
Electricity and magnetism	95
Radiation and the structure of matter	375
Mathematical and theoretical developments	65

experimentally and explaining thermodynamically the relation of the electromotive force in a cell to the temperature and concentration as well as the chemical nature of the constituents. This led directly to the specifications for the famous Carhart-Clark standard cell, and for the legal standard volt. The legal standard unit for the measurement of electric current is the international ampere, which depends upon the electrochemical equivalent of silver. The value of this constant was measured with great precision by Guthe in 1905. These and similar fundamental researches attained international recognition and contributed materially to the high standard of accuracy which now characterizes electrical measurements. In subsequent years, however, the primary interest of the department turned to other fields, and contributions to electrical theory have been less significant.

An exception should be made, however, for the recent direct measurements by Neil H. Williams of the charge per electron transported by a current crossing a vacuum gap. Although the electron charge had previously been known, it was only through indirect measurements on ions. Williams' value, of course, agreed with that determined by Millikan in 1913 for the charge upon a monovalent ion. The observations upon electrons were later extended and corroborated by similar measurements upon metallic ions.

Researches in electrical conduction through metals, gases, and high vacua, which established the corpuscular nature of electrical charges, led directly to the problem of the fundamental nature of matter, i.e., the constitution of atoms, molecules, and crystals. Bohr's theory of atomic structure, first announced in 1913, supplied a tremendous stimulus to such investigations, indicating a new line of attack through spectroscopic observations. It is not surprising that during the last three decades the major interest, and in fact almost the exclusive research activity, of the department should have been devoted to this field. The first spectroscopic studies at Michigan, published in 1911 by Randall, dealt with the emission of infrared (low-frequency) radiations by metallic vapors and the reflection of infrared rays by crystals. His measurements began near the end of the visible spectrum and extended to wave lengths about four times as great. As glass becomes opaque in this region it is necessary to dispense with lenses and use only mirrors in the optical system.

The dispersion is effected by means of a diffraction grating ruled upon a polished metal surface. These infrared rays can be detected neither by the eye nor by a photographic plate, but only through their heating effect, which is extremely minute. The temperature change resulting when they fall upon a sensitive thermopile gives rise to an electric current which is recorded by means of a galvanometer of high sensitivity. Randall brought the technique of these measurements from Tübingen, where he had been associated with one of the greatest of spectroscopists, Professor F. Paschen. No suitable apparatus being available on the market, it was necessary from the first to construct and adapt the equipment, including thermopiles, galvanometers, and mirrors. This development in measuring apparatus has been almost continuous in subsequent years, with vital contributions from all members of the group associated with this research, including Randall, Sleator, Barker, Meyer, Colby, Firestone, Hardy, Wright, and others.

In 1915 Sleator, working with Randall, set up a prism-grating spectrometer for the study of the molecular absorption of water vapor, the design of which has been frequently copied. The following year this instrument was used by Randall and Imes for their famous analysis of the absorption bands of hydrogen chloride. These studies mark the beginning of a long and continuous sequence of investigations upon the characteristic vibrational and rotational motions of various gaseous molecules, which have yielded much valuable information about the geometric form and actual dimensions of different molecules. Very important contributions in connection with the interpretation of the observed data have been made by Dennison and Colby.

In all, about one hundred and twenty papers dealing with spectroscopy of the infrared have been published, and this laboratory is generally recognized the world over as the principal center for such work. Major improvements in apparatus have been made from time to time, not only increasing precision and sensitivity, but also very greatly extending

the range of wave lengths which may be studied. With an instrument completed by H. M. Randall in 1936, consisting of a large recording spectrometer completely enclosed in a case which may be evacuated, measurements are possible to wave lengths more than two hundred times those of red light, in fact, practically to the lower limit for radio waves.

A second important type of spectroscopic investigation deals with visible and ultraviolet radiations, both from atoms and from molecules. In these the records are photographic. R. A. Sawyer and O. S. Duffendack, with their associates, have been responsible for most of this work, which is represented by some ninety-five papers. The earliest of these appeared in 1921. Studies of the excitation of various spectral lines from different atoms and their classification are of great interest not only from the standpoint of atomic mechanics but also because they find applications in rather widely separated fields. Astronomy and astrophysics, for instance, depend very much upon spectroscopic information for their determinations of the temperature and other physical conditions in stars and nebulae. Such observations may also be utilized for chemical analysis in the quantitative determination of very small traces of different metals. Duffendack has pioneered in this type of work and also in studies of the critical potentials of atoms and molecules through controlled impacts. Sawyer is responsible for recent developments in precision spectrochemical analysis, particularly of ferrous metals, a contribution of very considerable importance from the industrial point of view. He has been concerned also with measurements in the extremely short-wave ultraviolet region, and with the determination and interpretation of hyperfine structure in spectral lines.

The study of X radiation yields intimate and characteristic information regarding the structure of atoms and their geometrical arrangement in crystals. In 1920, when this field was just beginning to be systematized, G. A. Lind-say adopted it as his special interest, emphasizing particularly the precise measurement and classification of absorption edges. His first report appeared in 1922. Very shortly thereafter J. M. Cork began a program of work in the same field, extending the systematic classification of atomic levels to some of the less well-known elements. Of particular interest in this connection was his work on element No. 61, one of the very last chemical elements to be discovered. Cork also made some of the earliest grating measurements of the wave lengths of X rays, showing an inconsistency in the previous crystal measurements, which demanded a slight increase in the accepted value of the electron charge. This result has since been abundantly confirmed.

The optical gratings, by means of which wave lengths are determined, consist of polished metal surfaces ruled with parallel and equidistant lines. The distances between successive lines must be greater than the wave length measured, but preferably not much greater. Even the finest gratings, having perhaps thirty or forty thousand lines per inch, are very coarse in comparison with X rays. For the far infrared, on the other hand, gratings with twenty-five to one hundred lines per inch are required. Effective work throughout the spectrum is possible only when a considerable selection of suitable gratings is available, and the Department of Physics is peculiarly fortunate in this respect, since it possesses an excellent ruling machine (one of perhaps half a dozen such machines in existence). The development work in connection with this mechanism and in the preparation and ruling of surfaces

has been largely under the direction of Barker, since his infrared investigations were among the first which required gratings not obtainable elsewhere.

Entirely different methods must usually be employed for measurements in the range of radio waves. An interesting recent development in Williams' laboratory, however, involves the production of radio waves less than half an inch in length and their measurement by means of gratings built up of narrow metal strips. The problem of producing such waves is one requiring much ingenuity, since tubes having almost microscopic dimensions must be constructed, and never before have grating measurements of this sort been attempted. These radiations are found to yield further information concerning the structure of certain molecules.

The most recent and perhaps the most spectacular experimental development in atomic physics sponsored by this department is an attack upon the problem of nuclear constitution through artificial disintegration of atoms and induced radioactivity. It was begun by Cork in 1934, when he constructed a Van de Graaff generator designed to develop a potential difference of one million volts. This instrument was replaced in 1936 by the million-volt transformer equipment planned and assembled by H. R. Crane and by the cyclotron, for which Randall and Cork were responsible. The latter apparatus has a magnet weighing ninety tons, with pole pieces thirty-six inches in diameter. It is capable of accelerating ions by means of successive impulses up to speeds corresponding to twelve million equivalent volts. This instrument has made possible the production of a great variety of radioactive atoms which do not occur in nature and which are useful as tools in many new types of investigation. It also supplies neutrons in very large numbers. Researches in physics which are dependent upon the cyclotron include studies of nuclear energy levels, the production and measurement of gamma radiations, the upper limits of beta-ray energies, the scattering of neutrons, and the precise determination of atomic masses.

A very considerable portion of the output from the cyclotron is utilized in activities outside the Department of Physics. These include tracer chemistry, studies in plant and animal metabolism of the physiological effects of neutrons, and the treatment of certain diseases by radiotherapy.

During the decade 1915 to 1925 the accumulation of experimental data, particularly upon atomic problems, was so enormous and the necessary changes in point of view were so far-reaching that the department came to feel acutely the need for specialists in systematization and in interpretation. Throughout this period W. F. Colby had generously consulted and co-operated with various experimentalists, meanwhile carrying most of the responsiblity for instruction in theoretical physics. In 1923 Dr. Oskar B. Klein was appointed to the staff and assigned courses in mechanics and quantum theory. His contributions, both in the classroom and in the seminar, were of great value during the three years of his residence in this country. Otto Laporte, who had already attained distinction in the field of complex atomic spectra, was appointed in 1926. His analysis and interpretation of the spectrum of iron are especially well known. In 1927 the department materially enlarged the group in theoretical physics by the addition of D. M. Dennison, S. A. Goudsmit, and G. E. Uhlenbeck.

Dennison has made contributions of the very first rank in the field of molecular mechanics, co-operating effectively in the studies of infrared radiation and

band spectra. Several of his papers are very well known, in particular his discussion of ortho- and para-hydrogen, and the prediction regarding their separation, and his masterly summary of the mechanical problem of molecular vibrations.

Goudsmit's field is also that of complex atomic spectra. Uhlenbeck and he were the first to introduce the concept of electron spin which is now an indispensable element in the solution of all spectroscopic problems. This idea and its implications have also been extended by Goudsmit to the realm of nuclear structure and the mutual interaction of elementary particles. Both Uhlenbeck and Laporte have made significant contributions to quantum mechanics and also to purely mathematical developments upon which it depends.

It has always been the policy of the Department of Physics to co-operate to the fullest extent with other departments and research units whenever this can be done to advantage. For example, the Department of Engineering Research, since its organization, has maintained an extensive program in physics and has occupied space in the Randall Laboratory. One member of the departmental staff is assigned to each research project as consultant. These projects originate with various industrial organizations and have included such problems as noise reduction in automobiles and other mechanisms, the development of devices for testing and inspecting bearing surfaces, the improvement of spark plugs and ignition apparatus, and the spectrum analysis of steel and of metallic alloys. Judged by the satisfaction of its clients, the staff has a high record of success in the field of applied physics. Floyd Alburn Firestone (Case '21, Ph.D. Michigan '31) was appointed in 1923 as the first research physicist under this program, but since 1926 has been a member of the regular staff. Most of his contributions are in the field of acoustics, with particular emphasis upon industrial applications.

Another typical co-operative research has been carried on for some years with the assistance of the Medical School and a grant from the Rockefeller Foundation. This has developed, under Duffendack and Thompson, a spectroscopic procedure for the rapid quantitative analysis of body fluids for minute traces of various metallic constituents. Randall and Wright, also associated with this project, devised spectroscopic means for the detection by infrared measurements of several amino acids which are of great physiological importance.

A second association of physics and medicine has been developed, under a grant from the Rackham Fund, for the production and study of neutrons and artificially radioactive atoms and the determination of their physiological and therapeutic significance. The cyclotron and high-tension equipment are being utilized for these investigations.

The most recent addition to the departmental equipment is the electron microscope now being operated under Duffendack's supervision. It is an instrument of great promise and wide applicability, providing very much higher magnifications than are available by any other means. It is being applied in investigations on the structure of matter and also in the fields of bacteriology, biology, metallurgy, and engineering.

In any field of knowledge the University has two responsibilities: the discovery and interpretation of new truths and the conservation and transmission of existing information. Almost from the beginning of its scholarly activities the Department of Physics has developed both of these functions simultaneously. One of its very important scientific activities has been the production of textbooks of the first rank. The texts by

Carhart were particularly famous and were very widely used for many years.

The scientific standing which has been attained by the Department of Physics during the last two decades, its most active period, is due not simply to the individual eminence of various staff members, but arises in large measure from two other factors. One is the spirit of cordiality and co-operation which pervades the group, and the other, even more significant, is Randall's inspiring and sympathetic leadership, extending through almost the whole of this period.

The instrument shop. — A summary of the research activities in physics would not be complete without mention of the effective service rendered by the instrument shop. Its staff includes five trained instrument makers, under the supervision of Mr. Hermann Roemer, and a very skillful glass blower, Mr. Gunther Kessler. The shop not only supplies a service department, but also undertakes without hesitation and handles in the most competent way the construction of elaborate and delicate apparatus for all sorts of precision work. Of especial note is the ruling machine previously mentioned, which was designed and constructed here, and is now under the charge of Mr. Paul Weyrich, who also builds the sensitive thermopiles and makes the optical mirrors. Vacuum systems, gauges, and other apparatus of glass and quartz also are continually in demand.

The summer symposia on theoretical physics. — The summer symposia had their rather modest beginnings in the summer of 1923. In that year two nonresident lecturers, Professor K. T. Compton, then of Princeton University, and Professor F. A. Saunders, of Harvard University, were invited to give courses in modern physics. The results of this innovation were sufficiently gratifying to warrant a continuation of the policy, and during the next few years the following men were called as lecturers to the Department of Physics (the institutional connections given are those which they had at the time they lectured in the symposia at Ann Arbor):

• 1924 W. L. Bragg, University of Manchester, England
• 1925 P. D. Foote, Bureau of Standards
• W. P. Davey, Research Laboratory of the General Electric Company
• H. Fletcher, Research Laboratory of the American Telephone and Telegraph Company
• 1926 Dr. C. E. St. John, Mount Wilson Solar Observatory
• K. F. Herzfeld, University of Munich, Germany
• 1927 E. A. Milne, University of Manchester, England

The year 1927 closed the first period of development of the physics symposia. When this period was reviewed, several points stood out clearly. The nonresident lecturers had been stimulating both to the graduate students and to the regular staff of the department. The influence of the lecturers, however, had been purely local in character; their presence had not attracted any great attention outside of the University. Moreover, those lecturers who were primarily theoretical physicists had been able to give more to their audiences than had the experimental physicists. This was probably caused by the difficulty of satisfactorily describing an experimental technique — it must be learned from actual experience — and by the fact that the principal advances then being made in physics were in the field of theoretical research.

In the summer of 1928 a series of special courses was offered in theoretical physics; these were supplemented by informal colloquia on the most recent developments of the subject. Professor H.

A. Kramers, then of the Rijks Universiteit, Utrecht, Holland, gave courses on wave mechanics. Professor E. C. Kemble, of Harvard University, lectured on band spectra. In addition to the nonresident lecturers, S. A. Goudsmit and G. E. Uhlenbeck, who had recently been called to the University of Michigan, gave courses on the quantum theory of spectra and on Einstein-Bose and Fermi-Dirac statistics, respectively.

The success of this first symposium on theoretical physics was unmistakable. Not only were many graduate students attracted to the University to attend the courses, but, better still, a considerable number of distinguished visitors came, who participated in the colloquia and held discussions with the lecturers. These visitors were men, all holders of doctor of philosophy degrees, who were themselves actively engaged in productive research. It was possible during the ensuing year to trace in a number of articles in scientific journals ideas which had had their inception in the discussions of the symposium. The influence of this meeting was national and international rather than local.

The character of the summer symposia on theoretical physics was established by the symposium of the summer of 1928, and during the ensuing years it has only become more permanent and definitely determined. Each succeeding year has seen men of international reputation in physics come to Ann Arbor as lecturers; these men have played and are now playing the most prominent roles in the development of the subject. In addition to the nonresident lecturers, members of the regular physics staff have usually appeared on the programs. In Table IV are listed the symposium lecturers and their topics for the years 1929 to 1941. Except where explicitly stated otherwise, the courses ran for the full length of the session.

TABLE IV

1929 P. A. M. Dirac, Cambridge University, England Advanced Quantum Mechanics E. A. Milne, Oxford University, England Problems in Astrophysics Leon Brillouin, University of Paris, France Quantum Statistics K. F. Herzfeld, Johns Hopkins University Statistical Mechanics Edward U. Condon, Princeton University Introduction to Quantum Mechanics D. M. Dennison, University of Michigan Band Spectra

1930 Paul S. Ehrenfest, University of Leiden, Holland Problems in Modern and Classical Physics Enrico Fermi, Royal University of Rome, Italy Quantum Electrodynamics Philip M. Morse, Princeton University Quantum Mechanics (seven weeks) S. A. Goudsmit, University of Michigan Quantum Theory of Atomic Spectra G. E. Uhlenbeck, University of Michigan Applications of the Theory of Probability in Physics

1931 Arnold Sommerfeld, University of Munich, Germany Electron Theory of Metals (four weeks); Selected Problems of Wave Mechanics (four weeks)

TABLE IV (Cont.) Wolfgang Pauli, University of Zurich, Switzerland Problems of Nuclear Physics (four weeks); Application of Quantum Theory to Problems of Thermal Equilibrium (four weeks) H. A. Kramers, University of Utrecht, Holland Quantum Mechanics and Classical Models J. R. Oppenheimer, California Institute of Technology General Quantum Theory of Transitions (four weeks) W. F. Colby, University of Michigan Theory of Band Spectra G. E. Uhlenbeck, University of Michigan The Theory of Probability in Physics Otto Laporte, University of Michigan Quantum Theory of Atomic Spectra

1932 Werner Heisenberg, University of Leipzig, Germany Selected Problems in Quantum Mechanics Gregory Breit, New York University The Quantum Theory of Radiation and Dispersion S. A. Goudsmit, University of Michigan Theory of Hyperfine Structure of Spectral Lines D. M. Dennison, University of Michigan Theory of Band Spectra

1933 Niels Bohr, University of Copenhagen, Denmark The Foundations of Quantum Mechanics (two weeks) Enrico Fermi, Royal University of Rome, Italy Structure of the Atomic Nucleus J. H. Van Vleck, University of Wisconsin Recent Developments in the Theory of Magnetism S. A. Goudsmit, University of Michigan Structure of Atomic Spectra G. E. Uhlenbeck, University of Michigan Quantum Mechanics D. M. Dennison, University of Michigan Theory of Band Spectra

1934 George Gamow, Polytechnical Institute of Leningrad, Russia The Atomic Nucleus J. R. Oppenheimer, University of California The Theory of the Positron (three weeks) E. O. Lawrence, University of California Artificial Disintegration of Atomic Nuclei (four weeks) Thomas H. Johnson, Bartol Research Foundation Cosmic Rays (two weeks) Arthur H. Compton, University of Chicago Cosmic Rays (three lectures) G. E. Uhlenbeck, University of Michigan The Dirac Theory of the Electron (four weeks) D. M. Dennison, University of Michigan Introduction to Quantum Mechanics

1935 Enrico Fermi, Royal University of Rome, Italy Selected Subjects in Quantum Mechanics Felix Bloch, Stanford University The Quantum Theory of the Metallic State (four weeks) S. A. Goudsmit, University of Michigan Theory of Atomic Structure G. E. Uhlenbeck, University of Michigan Advanced Quantum Mechanics (four weeks)

1936 P. P. Ewald, Technische Hochschule, Stuttgart, Germany The Theory of the Solid State E. O. Lawrence, University of California The Design and Technique of Cyclotrons (four weeks) H. A. Bethe, Cornell University The Physics of High Speed Particles (four weeks) Edward U. Condon, Princeton University The Quantum Mechanical Treatment of Selected Problems (six weeks)

TABLE IV (Cont.) Gregory Breit, University of Wisconsin Special Topics in Nuclear Theory (two weeks) I. Rabi, Columbia University Nuclear Moments (two weeks) D. M. Dennison, University of Michigan Theory of Band Spectra Otto Laporte, University of Michigan Structure of Atomic Spectra

1937 Enrico Fermi, Royal University of Rome, Italy Theory of Beta Disintegration (three weeks) G. E. Uhlenbeck, University of Utrecht, Holland Nuclear Structure James Franck, Johns Hopkins University Photochemistry and Photosynthesis (one week) L. H. Thomas, Ohio State University Numerical Solution of Wave Functions (two weeks) F. N. D. Kurie, University of California Beta and Gamma Radiation (six weeks) Kasimir Fajans, University of Michigan Chemical Forces and Atomic Structure (three weeks)

1938 H. A. Kramers, University of Leiden, Holland Relativity and Spin; Radiation Theory P. P. Ewald, Cambridge University, England X Rays and Crystal Structure (one week) Gregory Breit, University of Wisconsin Nuclear Forces (four weeks) H. A. Bethe, Cornell University Nuclear Physics (three weeks) E. B. Wilson, Harvard University Infrared and Raman Spectra (two weeks) F. Seitz, General Electric Company Theory of the Solid State (two weeks)

1939 Enrico Fermi, Columbia University Cosmic Rays E. J. Williams, University of Wales Scattering of Cosmic Ray Particles (five weeks) G. Herzberg, University of Saskatchewan Band Spectra J. A. Wheeler, Princeton University The Interaction Between Radiation and the Nucleus (six weeks) G. B. B. M. Sutherland, Cambridge University, England Infrared Spectra (two weeks)

1940 E. P. Wigner, Princeton University Theory of the Atomic Nucleus R. Serber, University of Illinois Theory of the Meson (two weeks) W. H. Furry, Harvard University Theory of Radiation (two weeks) F. W. London, Duke University Low Temperature Physics (three weeks) B. Rossi, University of Chicago Cosmic Rays (two weeks) D. M. Dennison, University of Michigan Band Spectra G. E. Uhlenbeck, University of Michigan Theoretical Aspects of Cosmic Rays

1941 Wolfgang Pauli, Princeton University Recent Field Theories F. Seitz, University of Pennsylvania Theory of Solids (five weeks) J. Schwinger, University of California Nuclear Forces (four weeks) V. F. Weisskopf, University of Rochester Nuclear Reactions (two weeks)

As has already been mentioned, the summer symposia at Michigan have exerted an influence on physics which is both national and international in its scope. The distinguished guests have contributed much to the discussions and colloquia. These men have come from the important centers of physics in the United States and abroad. In Table V are listed the numbers of students and guests attending within a sequence of typical years.

The role which the symposia have played in the development of the Department of Physics has been of very real importance. The meetings have been

TABLE V

Year	Graduate Students	Guests
1928	43	18
1929	59	40
1930	51	25
1931	80	35
1932	79	29
1933	57	47
1934	62	39

an inspiration to the members of the regular staff as well as a direct practical aid in furthering many research programs. The influence of the symposia upon the number of graduate students in the department enrolled during the summer session is indicated in the foregoing table, although it must be remembered that these years also coincide with a period of rapid expansion of the Department of Physics, and it would be difficult to distinguish between the two effects. In addition to the increase in the number of graduate students, there has been a marked advance in the quality and degree of ability of the students, which may be largely attributed to the symposia.

Charles F. Meyer

George A. Lindsay

Daniel L. Rich

Ernest F. Barker

David M. Dennison

SELECTED BIBLIOGRAPHY

Calendar A Memorial Discourse on the Life and Services of George Palmer Williams. Catalogue … Catalogue and Register History of the University of Michigan. General Register Issue A Memorial Address on the Life and Services of Alexander Winchell. History of the University of Michigan. "Minutes of the University Senate," Henry Philip Tappan, Philosopher and University President. President's Report Proceedings of the Board of Regents … Records of the University of Michigan, 1817-1837. "The New Physics Laboratory." "The Early Days of the University of Michigan." American State Universities: Their Origin and Progress. University of Michigan. Catalogue of Graduates, Officers, and Members of the Faculties, 1837-1921. University of Michigan Regents' Proceedings …, 1837-1864. "Diary,"

Notes

• The numbers marked with an asterisk (*) are not net; they are the sums of the attendances for the academic year and summer school. The number of duplications in these years is not definitely obtainable; it would probably range from five to fifteen each year.
• The numbers marked with an asterisk (*) are not net; they are the sums of the attendances for the academic year and summer school. The number of duplications in these years is not definitely obtainable; it would probably range from five to fifteen each year.