The idea _that the motion of the sun_ does not necessitate any alteration in the system of Copernicus leads us to the utmost absurdity. If the earth is to move in the _invariable plain of its recurrent and closed ellipse_, it stands to reason, it cannot follow the sun, and the "circulation around the centre" at once falls to the ground. It is a very remarkable fact, that the astronomers of the by-gone century could, and those of the present century can believe, such as Copernicus, Kepler and Newton, had they been aware of the motion of the sun, would have set up the same system, the same laws and theories, _as they based exclusively on the theory of its being immoveable_. This fact is one of which we are right to be ashamed. The astronomers hug themselves, with great complacency, with the idea--which gradually becomes a delicious certainly--that they have mapped out the heaven very well, and that any change in the arrangement is a thing not to be thought of. If therefore any one of their fellows should get up--which has sometimes occurred--and say: "it is high time that we should clear up the science and subject this untenable theory to a strict examination and test," the immense majority of facultists and authorities proclaim unanimously "=non possumus=," which is after all but a lingual verification of the first law of the nature[2]. * * * * * Why is it that the astronomers of the present day are unwilling to take into consideration and to study the consequences arising from the motion proper to the sun, with reference to its own system? Why is it that they are unwilling to recognise or rather to grasp properly and to explain the apperceivable phenomena, which the motion proper to the sun, as seen from the surface of the earth, must produce on the apparently hollow sphere of the heaven? Monter d'une échoppe à un palais, c'est rare et beau; monter de l'erreur à la vérité, c'est plus rare et c'est plus beau. _Victor Hugo._ Il arrive fréquemment que la croyance universelle d'un siècle, croyance dont il n'était donné à personne de s'affranchir à moins d'un effort extraordinaire de génie et de courage, devient pour un autre siècle une absurdité si palpable qu'on n'a plus qu'à s'étonner qu'elle ait pu jamais prévaloir. _N. Tschernychewsky._ Litterature. 1. =Sta, sol, ne moveare.= _August Tischner._ Leipzig 1881-1882. Gustav Fock. 2. =Grösse, Entfernung und Masse der Sonne.= _August Tischner._ Leipzig 1882. Gustav Fock. 3. =Die Sonne und die Astronomie.= _K. Nagy._ Leipzig 1866. F. A. Brockhaus. 4. =Memoire sur le système solaire et sur l'explication des phénomènes célestes.= _Charles Nagy._ Paris 1862. Leibner. 5. =Considération sur les comètes, éléments de Cométologie.= _Charles Nagy._ Paris 1862. Leibner.