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.

Copernicus makes the sun to be motionless, and the scientific world bows before his authority. Then we have the recurrent curves, closed orbits (or ellipses) with their axes and their invariable plains; for the planets move round the centre of the fixed sun.

Whilst however learned men were striving with feverish ardour to confirm the system of Copernicus; whilst they were endeavouring to demonstrate in every possible way and by various means clearly, that the sun is immoveable: there came the discovery that the sun moves.

The astronomers of the past century proved that the sun not only has the apparent motion, which every one sees; but that it also has a motion proper to itself. Herschel commenced defining the course and direction of it, and now-a-days no one doubts the truth of this fact, it being the general opinion that not only the sun moves itself, but that nothing at all in the world is in a state of rest. Astronomers, however, are of opinion that this discovery is of no consequence whatever as regards the system of Copernicus, which is still considered by them to be the most correct of all and the only possible one. For more than a century there has not been found a single astronomer or scientific man, to whom it has occurred that the motion proper to the sun, might have, in some way or another, an influence on the present state of theoretical science. They all seem to regard this fact as an accident, involving no consequences and quite incapable of distracting them from their labours, which they continue to work in the same manner as is indicated in the system of Copernicus.

If an advancing motion is admitted to be the motion proper to the sun, the orbits traversed by the planets cannot be closed.

But the question may be asked: is it true that science contradicts itself in this way? We reply: Yes! astronomical observation has overtaken theoretical or explicative science. Theory has stood still.

In order to set their minds at rest, learned men explain what they wish to explain, and just as heavenly phenomena were accounted for according the systems of Ptolemæus, of Copernicus and of Tycho de Brahe, so too there will be no lack of good reasons to account for the motion proper to the sun; only history will tell us that the astronomers of the last but one decennium of the XIX^th century have taught by writing and speaking in their schools, that the sun is at the same time moving and not moving.

A science which cannot make any use of this immense discovery, nor deduce any application from it, does not possess any vital power; it is a dead science, it is strangled by those whose duty is to keep it alive, to lead it onwards to