A hundred years ago the science of spectroscopy, though not yet christened, may be said to have attained its majority and to be just entering on its period of full adult development. It was born, of course, with Newton's explanation of the formation of the spectrum, and for many years thereafter little of importance was added to what he had discovered. It was not, in fact, until the nineteenth century that anything of outstanding importance occurred, and then, in 1802, Wollaston (...) substituted a slit for the round hole through which Newton's sunlight passed into his prism, and thereby not only saw for the first time the dark lines in the solar spectrum but also took the first step towards the perfection of the spectroscope on which all later progress depended. The next step was taken by Fraunhofer who, in 1814, examined the spectrum through a telescope instead of letting it fall on a screen. The last essential improvement—the introduction of the collimator to make the light from the slit parallel before it entered the prism—was introduced in 1839 independently by Simms and Swan, so that before our period begins, the complete spectroscope existed, though it was not to be converted into a spectrograph, for photographing spectra, until much later. (shrink)

This paper follows up the analysis of relativity theory begun by Margenau and Mould, by including electromagnetic theory which in their treatment was tacitly accepted. It is shown that the experiments on which Margenau and Mould rely to establish the special theory of relativity actually confirm the mutual consistency of the Maxwell-Lorentz electromagnetic theory and the special relativity theory, but throw no light on the validity of the two theories taken jointly. It is further shown that a modification of the (...) rules of correspondence between the mathematical structure of the theories and immediate experience would bring the theories into agreement with an alternative relativity theory based on the Galilean instead of the Lorentz transformation. An experiment is suggested by which the need for such modification can be tested. A proof is then given that the rules of correspondence between the concepts of the special relativity theory (and therefore of current electromagnetic theory) and experience are not self-consistent, so that some modification of current ideas is essential. It is suggested that a generalisation of Maxwell's theory, in terms of Faraday's "ray vibrations" instead of Lorentz's static ether, might provide a satisfactory basis for a relativistic electromagnetic theory. (shrink)

It is a platitude that thought implies a subject and an object: the subject is the thinker, or the thinking mind, and the object is that which is thought about. This is probably the most elementary fact of consciousness, comprehensible alike to the child, the unreflecting man of affairs, and the philosopher, and it forms the natural startingpoint for philosophy. And indeed, one of the great divisions between philosophical systems is that which separates subjectivism on one hand from objectivism on (...) the other. Subjectivism professes to interpret the object in terms of the subject, and objectivism professes to interpret the subject in terms of the object. (shrink)

First published in 1951 to coincide with the British Festival, this book explores the developments in science which had occurred since the Great Exhibition of 1851. Covering the full range of scientific development which had emerged in that time – from fundamental physics to evolution and genetics, and from geology to medical surgery – this accessible collection of essays charts with impressive comprehension and clarity the momentous changes which had occurred in the pursuit of science since the mid-nineteenth century, and (...) ably demonstrates the appropriateness of citing the twentieth century as the advent of the scientific age. A Century of Science will appeal to those interested in the history of science, those wishing to ground their knowledge of specific scientific disciplines in a broader understanding of the subject, and also to the general reader who values scientific progress and the questions it continues to raise. (shrink)

On page 95 appears a review of a book by Professor E. A. Milne in which is described a new theory of the metrical character of the world and the interpretation, in the light thereof, of many important astronomical phenomena. Although the author states that his object is not to criticize the general form of the principle of relativity, there appears to be a fundamental distinction between the viewpoints of Einstein and Milne which is frequently emphasized and which it is (...) profoundly important to examine as minutely as possible, for if Professor Milne's claim is established the foundations of physics are essentially modified. The purpose of this article is to compare the outlooks implicit in Milne's theory and the theory of relativity, respectively, in order to see how far, if at all, current ideas require alteration. It should, be mentioned that, although Professor Milne speaks of his theory as “the principle of relativity in a much weaker form” and frequently uses the word “relativity” to describe it, we shall here, to prevent misunderstanding, restrict the meaning of the word to Einstein's theory. (shrink)