The design of the multiplied contrivances and adaptations exhibited by the eye is too obvious to need a formal statement. Comparatively few understand the wonderful mechanism of the eye; but we should consider it proof of idiotism, or insanity, for the weakest mind to doubt what is the object of the eye. This is, to be sure, a striking example. But out of the many organs of animals, how few are there of which we do not see the design! And as the subject is more examined, the few excepted cases are made still fewer. They are more numerous in plants, because we cannot so well understand them, and because of their microscopic littleness. They are so few, however, throughout all nature, that they never produce a doubt that, for every individual thing in creation, there is a distinct object. If we confine our views to the most simple parts of matter, we can see design in them. If we take a wider view, and examine those minor systems which are produced by the grouping of the elements of matter, we shall see design there; and if we rise still higher in our examination, and compare systems still more extensive, until we group all material things, wise and beautiful design is still inscribed upon all. In fine, creation is but a series of harmonies, wheel within wheel, in countless variety, yet all forming one vast and perfect machine. Examine nature as widely and as minutely as we may, we never find one part clashing with another part; no laws, governing one portion of creation, different from those governing the others. Amid nature’s infinitely diversified productions and operations we find but one original model or pattern. As Dr. Paley finely expresses it, “We never get amongst such original or totally different modes of existence as to indicate that we are come into the province of a different Creator, or under the direction of a different will.” All appears to have been the work of one mighty mind, capable of devising and creating the vast system so perfectly that every part shall beautifully harmonize with every other part; a mind capable of holding in its capacious grasp at once the entire system, and seeing the relation and dependence of all its parts, from the minutest atom up to the mightiest world. In short, the unity of design which pervades all creation is perfect, more so than we witness in the most finished machine of human construction; for
“In human works, though labored on with pain,
A thousand movements scarce one object gain;
In God’s, one single can its end produce,
Yet serves to second too some other use.”
Such are the wonderful contrivance, adaptation, and design which the material world every where exhibits. But the geologist carries us back through periods of immense antiquity, and digs out from the deep strata evidences of other systems of organic life, which have flourished and passed away; other economies, which have existed on the globe anterior to the present. And how was it with these? Had they any relation to the existing system? Were they governed by different laws, or are they all but parts of one great and harmonious system, embracing the whole of the earth’s past duration? We could not decide these questions beforehand; but geology brings to light unequivocal evidence that the latter supposition is the true one; that is, in the language of the poet,—
“All are but parts of one stupendous whole,
Whose body nature is, and God the soul.”
To present the evidence of this conclusion will be my object in this lecture.
In the first place, the laws of chemistry and crystallography, electricity and magnetism, have ever been the same in all past conditions of the earth.
Chemistry has attained to such a degree of perfection that the analyst can now determine the composition of the various vegetable, animal, and mineral substances which he meets, with an extreme degree of accuracy. In many instances, he can do this in two ways. He can always separate the elements which exist in a compound, and ascertain their relative quantity; and this is called analysis. And sometimes he can take those elements and cause them to unite, so as to form a particular compound; and this is called synthesis. By these methods he has ascertained that, amid the vast variety of substances in nature, there are only about sixty-four which cannot be reduced to a more simple form, and are therefore called elements, or simple substances. Now, the chemist finds that, when these elements unite to form compounds, certain fixed laws are invariably followed. They combine in definite quantities, which are always the same, or some multiple of the same weight; so that each element has its peculiar and invariable combining weight; and it cannot be made to combine in any other proportion. You may mix two or more elements together in any proportion, but it is only a certain definite quantity of each that will combine, while the rest will remain in excess. Hence the same compound substance, from whatever part of the world it comes, or under however diverse circumstances produced, consists of the same ingredients in the same proportion. These laws are followed with mathematical precision, and we have reason to believe that the same compound substance, produced in different parts of the world, never differs in its composition by the smallest conceivable particle. Indeed, with the exception of the planetary motions and crystallography, chemical combination is the most perfect example of practical mathematics to be found in nature.
Such are the laws which the chemist finds invariably to regulate all the changes that now take place in the constitution of bodies. What evidence is there that the same laws have ever prevailed? In the rocks we have chemical compounds, produced in all ages of the world’s history, since fire and water began to form solid masses. Now, these may be, and have been, analyzed; and the same laws of definite proportion in the ingredients, which now operate, are found to have controlled their formation. The oldest granite and gneiss, which must have been the earliest rocks produced, are just as invariable in their composition as the most recent salt formed in the laboratory. And the same is true of the silicates, the carbonates, the sulphates, the oxides, chlorides, fluorides, and other compounds which constitute the rocks of different ages. We never find any produced under the operation of different laws.
Now, the almost invariable opinion among chemists is, that the reason why the elements unite thus definitely is, that they are in different electrical states, and therefore attract one another. Hence the most important laws of electricity have been coeval with those of chemistry; indeed, they are identical; nor can we doubt, if such be the fact, that every other electrical law has remained unchanged from the beginning. And from the intimate connection, if not complete identity, between electricity and magnetism, it is impossible to doubt that the laws which regulate the latter are of equal antiquity with those of the former. Indeed, we find evidence in all the rocks, especially those which are prismatic and concretionary, of the active influence of galvanism and electro-magnetism in their production.
The reasoning is equally decisive to prove the unchanging character of the laws which regulate the formation of crystals. The chemist finds that the same substance, when it crystallizes, invariably takes the same geometrical forms. The nucleus or primary form, with a few exceptions, of no importance in the present argument, to which all these secondary forms may be reduced by change, is one particular solid, with unvarying angles; and all the secondary forms, built upon the primary, correspond in their angles. In short, in crystallography we have another example of perfect practical mathematics, as perfect as the theory.