manifestations of one and the same primordial agent. We can no longer question this general conclusion of all modern discoveries, Sénarmont explicitly says, though it is, as yet, impossible to formulate with precision its laws and its particular conditions. If this he true, and we hope we have proved it to be so, it is plain that those conditional particularities of which Sénarmont speaks, that is to say, those diversified manifestations of the sole agent to which he alludes, can depend only on differences ín the motions which impel it. Now, the very existence of these differences necessarily implies a coördinating and regulating intelligence; but how much more extreme is the necessity for such a cause in chemical phenomena, which display such endless complications issuing from that primal energy to which every thing in the last analysis is reduced! We have seen that the variety of those stable and homogeneous energies known under the name of simple bodies, the number of which is now increased to sixty, depends on the variety of the vibrations that each one of these little worlds performs. This is the earliest intervention of a principle of difference. This principle does not merely determine the multiplication of simple bodies; it also acts in any one element with such intensity that the same element can acquire very unlike properties and attributes. What things are more heterogeneous than the diamond and charcoal, or than common phosphorus and amorphous phosphorus? Yet charcoal and diamond are chemically identical, just as the two sorts of phosphorus are. These cases of isomery, which are quite numerous, attest with the strongest evidence the excessive variability of which combinations of force are capable. When we see the same elements, combined in the same weight-proportions, produce sometimes harmless substances, sometimes terrible poisons, in one case evolve colorless or dingy products, in another brilliant hues, we become convinced that primal matter is of little consequence in comparison with the weaver who arranges its threads, and knows beforehand what the aspect of the web will be. Besides, it is not alone in the whole that the formative principle is displayed; it shows forth also in the elements, considered individually, since every one of them exhibits tendencies, elective affinities, that bear witness to some obscure instinct toward harmonious completion.
There is not only a prodigious variety in the disposition of the atoms which make up molecules, and in the arrangement of the molecules among themselves, but this arrangement is governed, besides, by admirable geometric laws. The atoms that make up molecules are not heaped and flung together at random and in disorder; they enter into composition only in fixed proportions and in fixed directions. Marc-Antoine Gauclin has proved, in a late treatise devoted entirely to these refined inquiries, the existence of some of the most important laws in the geometry of atoms. .This ingenious and persevering writer demonstrates that all chemical molecules, whether they are fitted to
