Introduction to physical optics

Introduction to physical optics

VILLAT, HENKI. Lecons sur l’IIytlrotlynall~i(~~~~. 1929. West Virginia Geological Survey. County Reports. Pocahontas County. Two volumes. 1929. WIEN, ...

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VILLAT, HENKI. Lecons sur l’IIytlrotlynall~i(~~~~. 1929. West Virginia Geological Survey. County Reports. Pocahontas County. Two volumes. 1929. WIEN, W., ANDF. HARMS, editors. Handbuch der Experimentalphysik. Band 3, and Band 24, 2 Teil. Two volumes. 1930. WIESNER, JULIUS EON. Die Rohstoffe des Pflanzenreichs. \‘ierte Auflage. Bd. 1-2. 1927-1928. WOODHOUSE, THOMAS. The Preparation and W’eaving of .Artificial Silk or &iyOIl. 1929. World Almanac and Book of Facts. 1930. WYNN, A. E. Design and Construction of Formwork for Concrete Structures. No date.

BOOK

REVIEWS.

INTRODUCTION ~0 PHYSICAL OPTICS. By John Kellock Robertson, F.R.S.C., Professor of Physics, Queen’s University, Kingston, Canada. vii-422 pages, illustrations, 8~0, cloth. I\iew York, D. Van Nostrand Company, Inc., 1929. Price, $4.00. There is available a considerable collection of comprehensive modern texts on physical optics, and the author of this volume regards the field represented by those works and by books of a strictly elementary character as already well covered. In an intermediate stage of study which he describes as neither eleThe work is specifically mentary nor advanced, he finds another text is needed. addressed, on the one hand, to those students who at the outset of an intensive study of physics are laying a firm foundation for subsequent work on the theory of optics, and on the other hand, to those who will major in some other branch of physics for which a sound general knowledge of modern views of light will be essential. A generally characteristic feature is the obvious aim to insure a thorough assimilation of the topics discussed, and to that end the purely analytic matter is reinforced by numerous quantitative discussions and explanatory references which Despite the arouse interest and stimulate a capacity for sustained effort. profound changes which twentieth century progress has wrought in our ideas of matter and the propagation of radiant energy, the century-old universally accepted If it is to pass or at least be extensively modified wave theory still dominates. by the discontinuous emission of radiant-energy which is postulated by the quantum theory, it has proved a working hypothesis of incomparable value about which the magnificent structure of modern physics has been built. The new facts of physics, far reaching as they are, have not yet modified the practice of the science as a whole. Thus in this up-to-date work we find the subject matter developed according to the customary wave-theory and a continuous wave-front with appropriate digressions upon those phenomena accountable only on the new atomistic theory and on the discontinuous character of the interchange of radiant energy. The development of physical theory, particularly in its modern forms, often carry thr investigator into the most tortuous paths of mathematical science.

125 The author bears in mind that his work is not for a trained mathematician the

student

whose

mathematical

attainments

are

limited.

He

but for

accordingly

limits the deductive features to those which can be approached by algebraic and trigonometric processes; results which require transcendental processes are stated Such a program for a first reading of a subject without formal demonstration. is obviously consistent with the purpose of acquainting the reader with the great The quantity of qualitative information which is associated with the subject. author, however, is insistent on the acquisition of a facility in dealing also with quantitative results. Particularly is this stressed by the inclusion of an unusually complete introductory study of wave-motion. Reflectors, lenses, prisms and the telescope,

including

thick

lenses,

receive

the first attention and are very adequately treated by the uniform application of the Huygens principle, thus maintaining in the derivations the physical concepts The remainder of light propagation. This occupies about one-third the volume. covers more strictly the realm of physical optics, dispersion spectra, interference, polarization and lastly the electro-magnetic theory of light and the modern This division of the subject contains many development of the “new physics.” interference, and diffraction phenomena. half-tone photographs of spectra, These are a distinct help to the student who may, but probably will not, have the opportunity of viewing them all “ in the flesh.” The modern theories and developments are grouped in the final chapters and constitute an illuminating Since they have not yet modified the old outline of those important advances. and still useful working hypothesis of the school-book, they are rather matters for The book is indeed a thorough the post-graduate student and research specialist. introduction which closely approaches “ reduction to practice.” L. E. P. Par IKTRODLXTIONA UNE CONNAISSANCE S~IENTIFIQUE DES FMTS Mus~caux. Pius Servien. Collection du Suggestions Scientifiques pub54 pages, 8vo. liee 50s la direction de Leon Brillouin. Paris, Librarie Scientifique Albert Blanchard, 1929. Price 7.50 francs. This pamphlet is one of a collection of scientific suggestions published under the direction of Leon Brillouin. In this particular instance the author seeks to apply the approved methods of scientific analysis and investigation to the field of music. His introductory statement is to the effect that music quite often has a soothing and quieting effect; that this is due to the presence of a symmetrical relation between tone intervals and duration of the notes and that such a symmetry may be demonstrated graphically by plotting time as the abscissa against the intervals (in semitones) as the ordinate. Music is classified either as cyclic or linear. Cyclic music tends to calm the agitated mind; graphically it shows an enclosed space and is best expressed by the diatonic scale. On the other hand, linear music is rather similar to a continuous running chain, there is no letdown in the tension, there being a constant progression from one transformation to the next. Such music is best fitted to the chromatic or atomic scale. Here is outlined the several Part Two deals with the recognition of themes. types of transformation a theme may undergo and a graphical analysis made of the themes in “Tristan and Isolde.” Following this the author discusses the relations of timbre, number of notes, length of intervals, time and intensity ant1 the part 1:layed by each in the various transformations of a given theme.