MATHEMATICAL PHYSICS.
The memoirs presented to the Cambridge Philosophical Society on the occasion of the jubilee of Sir George Stokes, have been published in a stately volume by the Cambridge University Press. A year ago some four hundred men of science met at Cambridge to celebrate the fiftieth anniversary of the appointment of Sir George Stokes to the Lucasian professorship of mathematics, a chair held by Newton and a distinguished line of mathematicians. An official account of the proceedings, with a portrait of Professor Stokes, is given in the volume now issued. The seventy-two institutions sending delegates are arranged chronologically in the order of their foundation, and it is not unworthy of note that among the sixteen oldest institutions, the United States has five representatives, whereas Great Britain has thirteen universities and colleges younger than the Johns Hopkins University. The Rede lecture given by M. Alfred Cornu and entitled 'La théorie des ondes lumineuses,' is published in French, even the quotations from Newton's 'Opticks' being translated into that language. M. Cornu states that by 'une etude approfondie' of the 'Opticks,' his lecture shows that Newton favored Descartes's undulatory theory of light, rather than the emission theory usually attributed to him. The twenty-two memoirs that follow cover a wide range of subjects, nearly all of which have, however, a connection with the researches of Professor Stokes. They include three contributions from the United States, mathematical papers by Profs. E. W. Brown and E. O. Lovett, and a description by Professor Michelson of his echelon spectroscope.
In addition to this memorial volume, the Cambridge University Press, which is represented in America by The Macmillan Company, is at present publishing the collected papers of three eminent students of mathematical physics. The first volume of Lord Rayleigh's 'Scientific Papers' contains seventy-eight contributions published from 1869 to 1881. The early papers show the influence of Maxwell, Lord Rayleigh's predecessor in the chair of experimental physics at Cambridge, but it was apparently not until 1881 that he fully appreciated the importance of Maxwell's electro-magnetic theory of light. The papers on acoustics were followed by the publication in 1877 of the classical work on the 'Theory of Sound.' Lord Rayleigh, at an early period, treated various optical subjects, including some of the phenomena of color vision. His explanation of the blue color of the sky and his treatment of the resolving power of telescopes are well known. The contributions on optics and acoustics have been continued to the present time, but they by no means limit his interests. There are important papers on hydrodynamics and mathematics, and longer and shorter contributions on a great range of subjects in mathematical physics, the science which at the present day is perhaps of supreme importance.
The second volume of Professor Tait's 'Scientific Papers' contains those published since 1881. The first volume consisted of sixty papers, and this volume, which has followed with but little delay, adds seventy-three. As must be the case in collected papers, some are elaborate treatises while others fill only part of a single page; some are extremely technical while others were first published in the 'Encyclopædia Britannica' and the 'Contemporary Review.' Among the more elaborate papers are
