It is a somewhat remarkable fact that in this age of scientific reason the observation of the strictly orderly arrangement of phenomena in the solar system as a whole should not have led to some idea in the minds of philosophical workers of a similar order of phenomena in its separate parts, but the explanation lies generally in the continual attempts to bring natural phenomena into line with certain preconceived hypotheses, and more particularly to the almost universal acceptance of the doctrine of the direct transmission of energy from the sun to the earth and the final rejection or radiation of this energy into space. There is no denying the eminent plausibility of this doctrine. The evidence of Nature _prima facie_ may even appear to completely substantiate it. But we would submit that the general circumstances in which this doctrine is now so readily accepted are very similar to those which prevailed in more ancient times, when the revolution of the sun and stars round the earth was the universal tenet of natural philosophy. This conception, allied to the belief that the sole function of the celestial bodies was to provide light and heat to the terrestrial mass, appeared to be in strict accordance with observed phenomena, and held undisturbed possession of the minds of men for centuries, until it was finally demolished by Copernicus as the result of simple and accurate observation of and deduction from natural phenomena. At the present time, the somewhat venerable belief in the transmission of energy in various forms from the sun to the earth appears at first sight to be supported by actual facts. But a more rigid scrutiny of the evidence and of the mental processes must inevitably lead the unbiassed mind to the conclusion that this belief has no real foundation on truly scientific observation, but is entirely unsupported by natural phenomena. Every operation of Nature, in fact, when considered in its true relationships is an absolute denial of the whole conception. Like its predecessor relating to the motion of the sun and stars round the earth, the doctrine of energy transmission between separate masses in space such as the sun and the earth cannot be sustained in the face of scientific observation. This doctrine is found on investigation to be supported not by phenomena but by the conception of an elastic ethereal medium, of whose existence there is absolutely no evidential proof, and the necessity for which disappears along with the hypothesis it supports. It is, however, not proposed to discuss in any detail either the supposed transmission of energy from the sun to the planets or the arbitrary properties of the transmitting medium, but rather to adopt a more positive method of criticism by summarising briefly the evidential phenomena which show the cyclical nature of the whole terrestrial energy process, and which remove the basis of belief in such a transmission.