Differences of magnitude, of space, and of time, which overwhelm our feeble imaginations, vanish before the unity of plan of the Creator's thought. A crystalline molecule, which will not affect the finest balance, is a world, with an equator and poles of its own, and its central atom round which atomic satellites gravitate. Whether these atoms are infinitely small or infinitely great, whether the time of their revolutions is measured by thousandths of a second or by myriads of years, is of little importance so far as their gravitation (_ponderation_, or _poising_) is concerned. For this ponderation is absolutely identical, whether we call it _affinity_,--when speaking of the atomic movements of chemically decomposable matter; or _gravitation_ or _attraction_, when referring to those atoms of the great whole which we call stars, and whose metamorphic scale is far beyond the range of beings planted on the surface of one of the stellar atoms. However profound may be the researches of our astronomers, they will never attain to a knowledge of the metamorphoses of worlds. The spectacle of celestial spheres rising anew from their ashes, like "the Arabian bird" of fable, will be as impossible for them as the knowledge of the decompositions and recompositions of our material bodies would be for chemists, planted on the surface of an atom of carbon. How, from such a standpoint, could they contemplate the manifold forms of matter, and embrace at a glance all its changes?... Well, we are relatively as powerless as these imaginary denizens of an atom of matter, rooted as we are to the crust of a planet,--a molecule suspended in the eternal ocean. What shall we now say of the forms and movements of _living matter_? In the first place, that they are infinitely more varied and more changeful than those of inanimate nature. Next, that the difference between their metamorphoses is very wide. The eye can follow the transformations of a rock exposed to the decomposing action of the agents which surround us on every side. This action is calculable, and the elements which it has dissociated may be determined and weighed. The effects of the force, called either affinity or attraction, which maintains these elements united, are not beyond the range of our observation; tables of affinity, and of atomic weights, have been constructed, which enable the chemist to dominate over matter, just as the astronomer embraces the stars, the atoms of the world, by the law of universal gravitation.