Sir Edmund Whittaker F.R.S. (II)

A History of the Theories of Aether and Electricity.
Sir Edmund Whittaker. Thomas Nelson & Sons, 1910, 1950.
Volume II - The Modern Theories

Chapter 1. The Age of Rutherford
ions: particles that carry electric charges
Rutherford-Soddy - general theory on radioactivity pub 1902-3. They asserted that in the radioactive substances radium, thorium, and uranium, there is a continuous production of new kinds of matter, themselves radioactive; when several changes occur together they are not simultaneous but successive; radioactivity consists in this: that a certain proportion of the atoms undergo spontaneous transformation into atoms of a different nature; and these changes are utterly different from anything in chemistry; the number of atoms that disintegrate in unit time is a definite proportion of those present. The proportion is characteristic of the radioactive body and is constant for that body.
Re: chemical ether
1864: John A. R. Newlands and the 'Law of Octaves' - when the chemical elements Are arranged according to the numerical vAlues of their atomic weights, the 8th element starting from any given one is, in regard to its properties, closely akin to the first 'like the 8th note in an octave of music.' Newland's idea was Adopted and developed by D.I. Mendeleev, who arranged the elements in a periodic table. Elements which are chemically inseparable but have different atomic weights were called by Soddy, isotopes.
Rutherford: Structure of the atom, 1911
Like the solar system, a small + charge nucleus in center containing most of the mass of the atom and surrounded by - electrons (electrons with negative charge) orbiting like planets at distances the order of 10 -8 cm.
Chapt II. Relativity Theory of Poincare and Lorentz
p. 28 et seq: One of the most perplexing unsolved problems of late 19th c. science was determining the relative motion of the earth and the aether. The laws of Newtonian dynamics presuppose the knowledge of a certain set of systems of reference [inertial system of reference] Doctrine of the aether, justified by the undulatory theory of light, was generally regarded as involving concepts of rest and motion relative to the aether and thus a means of specifying absolute position. The failure of many promising attempts to measure the velocity of the earth with respect to the aether led to Poincare's saying in 1899 that absolute motion is indetectible in principle whether by dynamical optical or electrical means. "Our aether," he said, "does it really exist?" Also Lorentz in 1904 asserted the same general principle. On 24 Sept 1904 Poincare gave to a generalized form of this principle, the name The Principle of Relativity. "According to the Principle of Relativity, the laws of physical phenomena must be the same for a 'fixed' observer as for an observer who has a uniform motion of translation relative to him: so that we have not, and cannot possibly have any means of discerning whether we are, or are not, carried along in such a motion." And: "From all these results there must arise an entirely new kind of dynamics, which will be characterized above all by the rule, that no velocity can exceed the speed of light." [italics his]
p. 35: The notion of absolute fixity in space, which... was thought to be required by the theory of aether and electrons was shown in 1900-04 by the Poincare-Lorentz theory of relativity to be without foundation.
p. 42: theory of relativity had its origin in the theory of the aether and electrons.
p. 51: now he traces the connection of mass with energy--expressed by Planck in 1908 in the form of a unified definition of momentum, the equivalence of mass and energy
p. 64: "The phenomena studied in natural philosophy take place at a definite location at a definite moment, the whole constituting a four-dimensional world of space and time. The theory of relativity had now made it clear that the separation of this four-dimensional world into a three-dimensional world of space and an independent one-dimensional world of time may be effected in an infinite number of ways, each of which is distinguished from the others only by characteristics that are merely arbitrary and accidental. In order to represent natural phenomena without introducing this contingent element, it is necessary to abandon the customary three-dimensional system of co-ordinates and to operate in four dimensions."
Chap. III. Beginnings of Quantum Theory
(too technical)
Chap. IV. Spectroscopy in the Older Quantum Theory
atomic spectra- essentially a quantum phenomena.
Pauli exclusion principle (1924) - two electrons in a central field can never be in states of binding which have the same four quantum numbers
Chap. V. Gravitation
p. 151: From 1904 onwards the Newtonian law of gravitation was examined in the light of relativity theory of Poincare and Lorentz. 1907: Planck experiments indicated that the gravitational properties of a body are essentially of the same nature as its inertial properties. Now, said Planck, all energy has inertial properties, and therefore all energy must gravitate. Six months later Einstein published a memoir in which he introduced what he later called the Principle of Equivalence... i.e. a uniform gravitational field os physically equivalent to a field which is due to a change in the co-ordinate systems.
Followed up in 1911 w/important memoir in which he argued that since light is a form of electromagnetic energy, therefore light must gravitate, that is, a ray of light passing near a powerfully gravitating body such as the sun, must be curved; and the velocity of light must depend on the gravitational field.
p. 157: FitzGerald, Works, p. 313: "Gravity is probably due to a change of structure of the aether, produced by the presence of matter." (1894) F.'s aether was called by Einstein simply space or space-time and F.'s somewhat vague term 'structure' became with Einstein the more precise 'curvature.' Thus we obtain the central proposition of the Einsteinian theory 'Gravity is due to a change in the curvature of space-time, produced by the presence of matter.'
p. 158: "What differentiates the Einsteinian theory from all previous conceptions is that the older physicists had regarded gravity as merely one among many types of natural force - electric, magnetic, etc. - each of which influenced in its own way the motion of material particles. Space, whose properties were set forth in Euclidean geometry, was, so to speak, the stage on which the forces played their parts. But in the new theory gravity was no longer one of the players but part of the structure of the stage. A gravitational field consisted essentially in a replacement of the Euclidean properties by a much more complicated kind of geometry: space was no longer homogeneous or isotropic..." General Relativity was "essentially a geometrization of physics" (p. 192)
p. 174: In 1920 A.N. Whitehead published a criticism of General Relativity -- "I do not understand how the fixed conditions for measurement are to be obtained." Set forth an alternate theory in his The Principle of Relativity, 1922. Whitehead's doctrine is loosely described as fitting Einsteinian laws into flat space-time. The idea of mapping curved space of General Relativity on a flat space wAs later revived by N. Rosen (1940) who claimed it enabled a more direct explanation for the conservation of energy, momentum, and angular momentum, and also to account for "certain unexplained residuals" in the Michelson-Morley experiment.
Chap. VI. Radiation and Atoms in the Older Quantum Theory
(too technical, but p. 222 on diff kinds of statistics might be worth copying)
Chap. VII. Magnetism and Electromagnetism, 1900-26
(too technical)
Chap. VIII The Discovery of Matrix Mechanics
p. 253: Replacement of Rutherford planetary model of the atom with that of the "virtual orchestra" which emitted radiations of frequencies actually observed. Heisenberg saw that this idea of replacing the classical dynamics of the Rutherford atom by formulae based on the virtual orchestra could be applied in a far wider connection. He took as his primary aim to lay the foundations of a quantum-theoretic mechanics which should be based exclusively on relations between quantities that are actually observable. Previous investigators had found integrals of the classical equations of motion of the atomic system, and so had obtained formulae for the coordinates and velocities of the electrons as functions of the time. These formulae Heisenberg now abandoned, on the ground that they do not represent anything that is accessible to direct observation... and in their place he proposed to make the virtual orchestra the central feature of the theory."
Problems could thus be translated from the beginning into quantum mechanics.
Chap. IX. Discovery of Wave Mechanics.
(too technical)