Thus did the mind of man advance the first step toward the maturity of physical science, by attaining to a more comprehensive survey of the mundane system, and a more accurate knowledge of his own habitation, of this earthly planet. The next step in this sluggish progress was made by the chemical discoveries of modern times, and especially of the French chemists. In a merely negative point of view, these have been important, as establishing the fact that the old elements, water, for instance, and air, which had long been regarded as simple, are themselves decomposable into other constituents and aeriform parts. And, indeed, that such great powers of nature as these are, and must ever remain so long as the present constitution of the world shall last, could only subsist in the reciprocal dynamical relation of several conflicting forces, a profounder glance at nature would of itself have conjectured and presupposed. But in a positive sense, this second step has carried us very far toward the understanding of the hieroglyphics of nature. Those primary elements of things discovered and numbered by that chemical analysis which has subjected to its experiments almost every form and species of matter, constitute, as it were, the permanent material letters and consonants of the natural world around us. On the other hand, the vowels of human language are represented by the fundamental facts of the magnetism of the earth, together with the phenomena of electricity, the decomposition of light, and the chemical chain of the galvanic pile, in which the inner life of the terrestrial force, and of the eternally-moving atmosphere, as well as the soul whose pulse beats therein, finds an utterance, like a voice out of the lowest deep. And thus, by means of an alphabet of nature, which, however, is still most imperfect, we may hope to make a beginning, at least, and to decipher one or two entire words. But modern chemistry has made a more important advance toward a right understanding of nature as a whole. By analyzing and decomposing all solid bodies, as well as water itself, into different forms of a gaseous element, it has thereby destroyed forever that appearance of rigidity and petrifaction which the corporeal mass of visible and external nature presents to our observation. Every where we now meet with living elemental forces, hidden and shut up beneath this rigid exterior. The proportion of aqueous particles in the air is so great, that, if suddenly condensed, they would suffice for more than one flood. And a similar deluge of light would ensue, if all the luminous sparks which are latent in the darkness were simultaneously set free; and the whole globe itself would end in flame, were all the fiery elements that are at present dispersed throughout the world to be at once disengaged and kindled. The investigation of the salutary bonds which hold together these elementary forces in due equilibrium,