scheme.

It is on these principles, allied with the great generalisations with respect to the conservation of matter and energy, that this work is founded. As the result of a long, varied, and intimate acquaintance with Nature, and much experimental research in many spheres, the author has reached the conclusion, already foreshadowed in Terrestrial Energy, that the great principle of energy conservation is true, not only in the universal and generally accepted sense, but also in a particular sense with respect to all really separate bodies, such as planetary masses in space. Each of these bodies, therefore, forms within itself a completely conservative energy system. This conclusion obviously involves the complete denial of the transmission of energy in any form across interplanetary space, and the author, in this volume, now seeks to verify the conclusion by the direct experimental evidence of terrestrial phenomena.

Under present-day conditions in science, the acceptance of the ordinary doctrine of transmission across space involves likewise the acceptance of the existence of an ethereal substance which pervades all space and forms the medium by which such transmission is carried out. The properties of this medium are, of course, precisely adapted to its assumed function of transmission. These properties it is not necessary to discuss, for when the existence of the transmission itself has been finally disproved, the necessity for the transmitting medium clearly vanishes.

PART I

GENERAL STATEMENT

1. Advantages of General View of Natural Operations

The object of this statement is to outline and illustrate, in simple fashion, a broad and general conception of the operation and interaction of matter and energy in natural phenomena.

Such a conception may be of value to the student of Nature, in several ways. In modern times the general tendency of scientific work is ever towards specialisation, with its corresponding narrowness of view. A broad outlook on Nature is thus eminently desirable. It enables the observer to perceive to some extent the links uniting the apparently most insignificant of natural processes to those of seemingly greater magnitude and importance. In this way a valuable idea of the natural world as a whole may be gained, which will, in turn, tend generally to clarify the aspect of particular operations. A broad general view of Nature also leads to the appreciation of the full significance of the great doctrines of the conservation of matter and energy. By its means the complete verification of these doctrines, which appears to be beyond human experiment, may be traced on the face of Nature throughout the endless chain of natural processes. Such a view also leads to a firm grasp of the essential nature and qualities of energy itself so far as they are revealed by its general function in phenomena.

2. Separate Mass in Space

In the scheme now to be outlined, matter and energy are postulated at the commencement without reference to their ultimate origin or inherent nature. They are accepted, in their diverse forms, precisely as they are familiar from ordinary terrestrial experience and phenomena.

For the purpose of general illustration the reader is asked to conceive a mass of heterogeneous matter, concentrated round a given point in space, forming a single body. This mass is assumed to be assembled and to obtain its coherent form in virtue of that universal and inherent property of matter, namely, gravitative or central attraction. This property is independent of precise energy conditions, its outward manifestation being found simply in the persistent tendency of matter on all occasions to press or force itself into the least possible space. In the absence of all disturbing influences, therefore, the configuration of this mass of matter, assumed assembled round the given point, would naturally, under the influence of this gravitative tendency, resolve itself into that of a perfect sphere. The precise magnitude or dimensions of the spherical body thus constituted are of little moment in the discussion, but, for illustrative purposes, it may, in the meantime, be assumed that in mass it is equivalent to our known solar system. It is also assumed to be completely devoid of energy, and as a mass to be under the influence of no external constraint. Under these conditions, the spherical body may obviously be assumed as stationary in space, or otherwise as moving with perfectly uniform velocity along a precisely linear path. Either conception is justifiable. The body has no relative motion, and since it is absolutely unconstrained no force could be applied to it and no energy expenditure would be required for its linear movement.

3. Advent of Energy—Distortional Effects

Nature, however, does not furnish us with any celestial or other body fulfilling such conditions. Absolutely linear motion is unknown, and matter is never found divorced from energy. To complete the system, therefore, the latter factor is required, and, with the advent of energy to the mass, its prototype may be found in the natural world.

This energy is assumed to be communicated in that form which we shall term "work" energy (§§ 13, 31) and which, as a form of energy, will be fully dealt with later. This "work" energy is assumed to be manifested, in the first place, as energy of motion. As already pointed out, no expenditure of energy can be associated with a linear motion of the mass, since that motion is under no restraint, but in virtue of the initial central attraction or gravitative strain, the form of energy first communicated may be that of kinetic energy of rotation. Its transmission to the mass will cause the latter to revolve about some axis of symmetry within itself. Each particle of the mass thus pursues a circular path with reference to that axis, and has a velocity directly proportional to its radial displacement from it.

This energised rotating spherical mass is thus the primal conception of the energy scheme now to be outlined. It will be readily seen that, as a primal conception, it is essentially and entirely natural; so much so, indeed, that any one familiar with rotatory motion might readily predict from ordinary experience the resulting phenomena on which the scheme is, more or less, based.

When energy is applied to the mass, the first phenomenon of note will be that, as the mass rotates, it departs from its originally spherical shape. By the action of what is usually termed centrifugal force, the rotating body will be distorted; it will be flattened at the polar or regions of lowest velocity situated at the extremities of the axis of rotation, and it will be correspondingly distended at the equatorial or regions of highest velocity. The spherical body will, in fact, assume a more or less discoidal form according to the amount of energy applied to it; there will be a redistribution of the original spherical matter; certain portions of the mass will be forced into new positions more remote from the central axis of rotation.

4. The Gravitation Field

These phenomena of motion are the outward evidence of certain energy processes.