The general public is helpless before any supposedly scientific statement. It may judge vaguely by the standing of the paper or magazine or book containing it, by the name of the writer or by the general tone in which the article is written. But it cannot judge definitely by comparison with relevant facts or by critically examining the logic of the deductions, for the general public lacks both knowledge of the relevant facts and training in logical criticism. That a man should invent a microscope which will enable one to see objects a million times as small as can be seen with the naked eye seems no more questionable to the general public than that a man should cause unfertilized eggs to develop. Yet the first would be impossible while the second has been possible, probable, and still more lately proved. Guidance in scientific matters should be welcome if only for the protection thus given against fraudulent medicines, bogus inventions and nonsensical enterprises. PHYSICIST. SCIENTIFIC LITERATURE. _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 étude 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.