Astronomical science, at the present day insists upon the system of Copernicus, which, as is well known, is based upon the theory _of a fixed sun_, and remains convinced of the incontrovertible truth and importance of this system, even after it has become an incontestable fact, that the sun changes its position; endeavouring to explain away this discrepancy by the sophism, that the sun may be considered as _in a condition of rest_. But the smallest movement of the sun overthrows the entire fabric of Copernicus. Unless we take into account the observations, made for the last 3000 years, respecting the movement of the sun in space, it is impossible to comprehend the solar system and its movements. Theory must take notice of the phenomena of the sun's own movement and dare not cloak it under imaginary causes; for so long as the motion of the sun is ignored, it is impossible to know thoroughly the motion of the earth which follows it, and if the motion of the earth be not known, it is also impossible to know the motion of the other heavenly bodies, belonging to the solar system, as seen from the earth. In a word, the astronomical theory, as it is now generally accepted and believed to be the only and doubtless true, is wholly untenable, requiring _a total and essential_ reformation; astronomical authors cling to J. H. Mädler's assertion, that every body will understand the impossibility for an astronomer of our time to enter upon any other system even by way of trial. If this theory be converted into a _dogma_, stagnation must commence and all progress becomes impossible. In the history of science and its advance, we find that there have been at all times new theories propounded, which had often to be changed later on, or even set aside by others diametrically opposite. The principal circumstance which renders the system of Copernicus impossible, is that the orbits of the planets _are considered as closed curves around the sun_. This view has frequently been attacked; but it is maintained by astronomers, as it is requisite for the elucidation of the system. Still it is evident that if the centre of attraction moves forward the bodies attracted by it _cannot move around it_. Let us examine the system of Copernicus. Ptolemæus first introduced his system among the ancients. The earth was the fixed centre of the world and around it moved the moon, the sun, the planets and the stars. This system lasted for XV centuries. The Ptolemaic system was modified by Copernicus, and the system of Copernicus was simply the inversion of the Ptolemaic. The sun took the place of the earth. In the centre was a fixed point (earth or sun), around which the planets moved in larger or smaller orbits. The main feature of both systems is that one of the heavenly bodies is _stationary, in order that the others may travel round it_.