exceeding three years. The most fundamental subjects will be arranged so as to recur at regular intervals, while other more special topics will vary from time to time. The general object of the instruction will be (1) to furnish the student an adequate mathematical basis for successful work in Celestial Mechanics; (2) to give experience and preliminary training in the work of observation and reduction; (3) to direct research work in Celestial Mechanics.

FACILITIES

For instruction in Practical Astronomy a student's observatory is maintained, equipped with a modern Warner & Swasey equatorial telescope of 61⁄2 inches' aperture, provided with a filar micrometer, a 5-inch refractor, a 3-inch Bamberg transit instrument, a Bamberg universal instrument, a Riefler sidereal clock, a chronometer, and various smaller accessories. The laboratory courses offered by the Department of Physics afford excellent preliminary training for the work in Astrophysics.

In the work at the Yerkes Observatory, the advanced student is made familiar with modern methods of research in various branches of Practical Astronomy and Astrophysics. The rapid development of the latter science within the last two decades has been fully recognized in the equipment of the Observatory; the special laboratory facilities make many investigations possible which cannot be carried on where the equipment is less complete. In general, the work in progress during the year 1909-10 will include: Researches in solar physics with the spectroscope, spectroheliograph, and photoheliograph; micrometric observations of double stars, planets, satellites, nebulae, and comets; photographic studies of stellar spectra and determinations of motions in the line of sight; photography of star clusters, nebulae, etc.; photographic investigations of stellar parallax; research in visual and photographic photometry; special astrophysical researches. The opportunity of taking part in these investigations is deemed of more advantage to the qualified student than set courses of instruction; but regular programmes of work, with courses of collateral reading, will be laid out as conditions may require.

ADMISSION TO YERKES OBSERVATORY

The Yerkes Observatory is open only to graduate students who have completed the necessary preliminary studies and have had the requisite experience in practical laboratory and observatory work. Students wishing to work at the Observatory should first consult the Director of the Yerkes Observatory, Williams Bay, Wis., and obtain his approval.

DEGREES

The Master's degree.- Students working for a Master's degree in Astronomy are advised to choose three majors of graduate work in the Department of Physics, and six majors in the Department of Astronomy, the last from courses numbered 5 to 29.

The degree of Doctor of Philosophy.—The courses prescribed for the Master's degree will meet the requirement for the Doctor's degree, where Astronomy is the minor subject.

Candidates for the Doctor's degree, with Astronomy as major subject, are expected to make their secondary subject either Mathematics or Physics. Students intending to specialize in the lines of Astrophysics will be required to take the work in Theoretical Physics, Advanced Experimental Physics, Sound and Light, and Physical Manipulation. The courses in Astronomy which will be required depend on the phase of the subject which the candidate elects for his special work, and will be arranged for each candidate during the progress of his work.

CLUB

The Departmental Club meets fortnightly for the review of memoirs and books, and for the presentation of results of research. The club is conducted by the members of the faculties of Mathematics and Mathematical Astronomy. Graduate students of Mathematical Astronomy are expected to attend regularly, and, so far as possible, to participate actively in the meetings of the club.

SEQUENCE OF EARLY COURSES

Undergraduate students who desire to specialize in Astronomy are recommended to take course 36 and its antecedents in Mathematics, and courses 3, 5, 6, 7, 10, 22, and 23 in Astronomy, as a basis for further work.

COURSES OF INSTRUCTION

At the University

JUNIOR COLLEGE COURSES

3. Descriptive Astronomy.-An elementary course, dealing with fundamental facts, principles, and methods. Frequent access to the observatory. Mj. Winter and Spring Quarters, DR. MACMILLAN; Mj. Spring Quarter, ASSOCIATE PROFESSORS MOULTON AND LAVES.

4. Introduction to Surveying.-(Mathematics 5). Mj. Spring Quarter, DR. MACMILLAN.

SENIOR COLLEGE COURSES

5. Analytic Mechanics, I.-An introductory course. Prerequisite: Mathematics 27. Mj. Autumn Quarter, ASSOCIATE PROFESSOR LAVES.

6. Analytic Mechanics, II.- Prerequisite: Astronomy 5. Mj. Winter Quarter, AssOCIATE PROFESSOR LAVES.

7. Spherical and Practical Astronomy.-Prerequisite: Mathematics 27 and Astronomy 3. 11⁄2 Mjs. Spring Quarter, ASSOCIATE PROFESSOR LAVES. 10. Elementary Celestial Mechanics.-Prerequisite: 3 and Plane Analytics. Mj. Autumn and Winter Quarters, ASSOCIATE PROFESSOR LAVES.

GRADUATE COURSES

22. Introduction to Celestial Mechanics, I.-Helmholtz's theory of the heat of the sun. Central forces; demonstration of law of gravitation; problem of two bodies; the ten integrals of planetary motion; considerations on perturbations. Prerequisite: course 5. Mj. Winter Quarter, DR. MACMILLAN.

23. Introduction to Celestial Mechanics, II.-Properties of conic section motion, special cases of the problem of three bodies; method of variation of parameters; considerations on absolute perturbations; determination of two geocentric distances from the observations; determination of elements, and methods of improving them; variations of elements. Prerequisite: course 22. Mj. Spring Quarter, DR. MACMILLAN.

50. Modern Theories of Analytic Differential Equations with Applications to Celestial Mechanics.-(See XVII, 127.) 3Mj. Autumn, Winter, and Spring Quarters, ASSOCIATE PROFESSOR MOULTON.

31, 32, 33. Research Courses at the Observatory.-Prerequisites: See Admission to Yerkes Observatory, p. 342. DMj. Each Quarter, PROFESSORS AND INSTRUCTORS resident at Yerkes Observatory..

XIX. THE DEPARTMENT OF PHYSICS

OFFICERS OF INSTRUCTION

ALBERT ABRAHAM MICHELSON, PH.D., Sc.D., LL.D., F.R.S., Professor and Head of the Department of Physics.

CHARLES RIBORG MANN, PH.D., Associate Professor of Physics.

ROBERT ANDREWS MILLIKAN, PH.D., Associate Professor of Physics.

CARL KINSLEY, A.M., M.E., Associate Professor of Physics.

HENRY GORDON GALE, PH.D., Assistant Professor of Physics.

WILLIAM ROSS HAMM, A.B., Assistant in Physics.

GEORGE WINCHESTER, PH.D., Professor of Physics, Washington and Jefferson University (Summer Quarter, 1909).

J. HARRY CLO, S.B.

FELLOWS, 1909-10

WILLIAM HENRY KADESCH, A.B.

HARVEY BRACE LEMON, S.B.

EDWARD JAMES MOORE, A.B., A.M.

JAMES REMUS WRIGHT, S.B.

INSTRUCTIONAL WORK

The instructional work in Physics is directed toward the following ends: (1) The training of original investigators in physics; (2) the training of men competent to fill college and university positions as teachers of physics; (3) the training of teachers of physics for secondary schools; (4) the training of pre-engineering and pre-medical students for later professional work; (5) the training of the general student in scientific methods of work, and in the understanding of the place of physical science in the modern world. From the most elementary to the most advanced courses, the laboratory and the problem method of instruction are emphasized.

FACILITIES

The Ryerson Physical Laboratory is planned with especial reference to offering the best facilities for research work, the entire lower floor being given up to private research rooms. A well-equipped shop, with skilled instrument makers, furnishes opportunity for the construction of special pieces of research apparatus. The equipment has been selected with reference to the needs of research, and includes spectroscopic instruments of highest power, electrical apparatus for work with alternating and direct currents through all ranges of potential, and appliances for high and for low temperature work, including a liquid air plant. The library department is well

equipped for research purposes. A physics club is conducted by some member of the Department, and meets fortnightly for the discussion of the results of research work done in the Ryerson Laboratory and elsewhere.

DEGREES

All candidates for the S.B. degree who elect their major work in Physics are required to take courses 3, 4, and 5, and either six majors selected from courses 11, 12, 13, 15, 16, 17, 18, and 25, or three of these and three Senior College courses in one of the following departments: Mathematics, Astronomy, Chemistry, Geology, or Geography. Pre-engineering students are required to take courses 3, 4, and 5; pre-medical students are required to take courses 3 and 4.

The Master's degree.-Candidates for the Master's degree in Physics are required to take 8 majors in physics and related subjects, and to present in addition a thesis embodying the results of a laboratory problem. All courses in the Department numbered 11 or above, except course 20, will be counted in satisfaction of this requirement.

The degree of Doctor of Philosophy.-Candidates for the Doctor's degree, with Physics as a minor subject, must take courses 3, 4, and 5, and six of the following: 11, 12, 13, 15, 16, 17, 18, 25, 31-36, 51, 52, 56, 57, 58, and 59. When physics is one of two minor subjects, the courses must be arranged by consultation with the Department.

All candidates for the Doctor's degree, with Physics as the major subject, must take the following courses: 3, 4, 5, 11, 12, 13, 15, and 25, or their equivalents; 3 majors selected from courses 16, 17, 18, 37, 38, and 39; courses 31-36, and three additional graduate lecture courses selected by the student. Each candidate must also present a thesis embodying the results of original research in some subject approved by the Department. The time required for the thesis work generally varies from three to six quarters.

PREPARATION FOR TEACHING

Students preparing to teach physics in secondary schools are expected to have completed courses 3, 4, 5, 14, and 25, and not less than three of courses 11, 12, 13, 15, 16, 17, and 18. See also courses in Physics in the School of Education.

COURSES OF INSTRUCTION

JUNIOR COLLEGE COURSES

1. Elementary Physics.-A first course in the elements of Physics designed primarily for students who do not present entrance Physics. Autumn Quarter, ASSISTANT PROFESSOR GALE.

2. Elementary Physics.-A continuation of the preceding course, covering the subjects of electricity, sound, and light. Prerequisite: course 1. Mj. Winter Quarter, ASSISTANT PROFESSOR GALE.

3. Mechanics, Molecular Physics, and Heat.—A general college course in Mechanics, Molecular Physics, and Heat, presented mainly from the experimental point of view. Prerequisite: Entrance Physics, or course 2. ̄Mj. Summer Quarter, 2 sections, PROFESSOR WINCHESTER AND MR. HAM. Autumn Quarter, 3 sections, ASSOCIATE PROFESSORS KINSLEY, MANN, AND MILLIKAN; Winter Quarter, ASSOCIATE PROFESSOR KINSLEY; Spring Quarter, ASSOCIATE PROFESSOR MANN.

4. Electricity, Sound, and Light.-A general college course in Electricity, Sound, and Light, presented mainly from the experimental point of view, and involving the performance of eighteen laboratory exercises in electricity, four in sound, and six in light. Prerequisite: Physics 3. Mj. Summer Quarter, 2 sections, AssOCIATE PROFESSORS MILLIKAN AND MR. HAM; Winter Quarter, 2 sections, ASSOCIATE PROFESSORS MANN AND MILLIKAN; Spring Quarter, ASSOCIATE PROFESSOR KINSLEY.

5. Lecture Demonstration Course.-A course of lectures, demonstrations, and recitations supplementing courses 3 and 4 and completing a year's work in college Physics. Recent discoveries and developments in Physics are given especial attention. 5 hours a week. Prerequisite: Physics 4. Mj. Summer Quarter, ASSISTANT PROFESSOR GALE; Spring Quarter, ASSOCIATE PROFESSOR MANN.

6. General Survey of Physical Science.-A lecture demonstration course in which familiar physical phenomena are presented and discussed with reference both to their scientific interpretation and to their relations to modern life. Primarily for Arts students. Not accepted in satisfaction of specific requirements in Physics. ASSOCIATE PROFESSOR MANN. [Not given in 1909-10.]

SENIOR COLLEGE COURSES

11. Heat and Molecular Physics.-A lecture course for advanced and graduate students, covering the Kinetic Theory, Capillarity, Elementary Thermodynamics, Solution, and Electrolysis. Prerequisite: Physics 4 and Calculus. Mj. Winter Quarter, ASSOCIATE PROFESSOR MILLIKAN.

12. Light.-A lecture course for advanced students covering the more important sections of geometrical and physical optics. [Not given in 1909–10.]

13. Electricity and Magnetism.-A course of advanced work in theoretical Electricity and Magnetism, intended to supplement the work in General Physics or to prepare for graduate work. Prerequisite: Physics 4 and Calculus. ASSOCIATE PROFESSOR KINSLEY. [Not given in 1909-10.]

14. The Pedagogy of Physics.-A course designed for teachers of Physics in high schools, consisting of lectures and discussions upon choice of subjectmatter and methods of presentation best suited to elementary courses in Physics. Prerequisite: courses 3, 4, and 5, or equivalents. M. First Term, Summer Quarter, ASSOCIATE PROFESSOR MILLIKAN.

15. Mechanics and Wave Motion.-A lecture course on the physical meaning and the mathematical derivation of the fundamental equations of Mechanics and Wave Motion. Prerequisite: Physics 4 and Calculus. Mj. Autumn Quarter, 2:00, ASSISTANT PROFESSOR GALE.

16. Experimental Physics (Advanced): Molecular Physics and Heat.—A course of advanced laboratory work involving the determination of vapor pressures and densities, coefficients of friction of gases and liquids, molecular electrical conductivities, freezing- and boiling-points, latent and specific heats, high and low temperatures, radio-active constants, etc. Prerequisite: course 4. Mj. Spring Quarter, ASSOCIATE PROFESSOR MILLIKAN.

17. Experimental Physics (Advanced): Light.-A course of advanced laboratory work in Light, consisting of accurate measurements in diffraction, dispersion, interference, and polarization. Prerequisite: course 4. Mj. Autumn Quarter, ASSOCIATE PROFESSOR MANN.

18. Experimental Physics (Advanced): Electricity and Magnetism.— Laboratory work of the same grade as courses 16 and 17, but consisting of measurements in Electricity and Magnetism. Prerequisite: Mathematics 27 and Physics 4. Mj. Summer Quarter. Mj. Winter Quarter, ASSOCIATE PROFESSOR KINSLEY.

20. Physical Manipulation. A series of exercises not provided in the regular courses of Experimental Physics, but important to the teacher or advanced student. It consists of the following groups: