OCR Text |
Show CAUSES OF ERROR IN while, on the other hand, there can be little dou?t, although the reader may, perhaps, smile at the bare suggestiOn of such an 'd tl1at an amphibious being, who should possess our 1 ea, . d h · 1 faculties, would still more easily arnve at soun t eoretlca opinions in geology, since h.e might behold, on the one hand, the decomposition of rocks m the atmosphere, and the transportation of matter by run~ing ~ater ; and, on the. other, examine the deposition of sediment m the sea~ and the !~bedding of animal remains in new strata. H~ might ascertam, by direct observation, the action of a mountam torrent, as well as of a marine current; might compare the products of volcano~ on the land with those poured out beneath the waters ; and might mark, on the one hand, the growth of the forest, and on the other that of the coral reef. Yet, even with these advantages, he would be liable to fall into the greatest errors when endeavouring to reason on rocks of subte~ranean o~igin. He w?uld seek in vain, within the sphere of his obscrvat10n, for any direct analogy to the process of their formation, and would there~ore be in danger of attributing them, wherever they ar~ upraised to view, to some "primeval state of nature." But If -we may be allowed so far to indulge the imagination, as to suppose a being, entirely confined to the nether world-some '' dusky melancholy sprite," like Umbriel, who could "flit on sooty pinions to the central earth," but who was never permitted to " sully the fair face of light," and emerge into the regions of water and of air; and if this being should busy himself in investigating the structure of the globe, he might frame theories the exact converse of those usually adopted by human philosophers. He might infer that the stratified rocks, containing shells and other organic remains, were the oldest of created things, belonging to some original and nascent state of the planet. " Of these masses," he might say, " whether they consist of loose incoherent sand, soft clay, or solid rock, none have been formed in modern times, Every year some part of them are broken and shattered by earthquakes, or melted up by volcanic fire; and, when they cool down slowly from a state of fusion, they assume a crystalline form, perfectly distinct from those inexplicable rocks which are so regularly bedded, and contain stones full of curious impressions and fantastic markin~s. 'fhis process cannot have been carried on for an indefimte time, for in that case all the sh·atified rocks would long ere Oll:OJ.OGTCA L TIIEORIES. 83 this have been fused and crystallized. It is therefore probable that the whole planet once consisted of these curiously· bedded formations, at a time when the volcanic fire had not yet been brought into activity. Since that period there seems to ?ave been a g:adual development of heat, and this augmentatiOn we may expect to continue till the whole globe shall be in a state of fluidity and incandescence." . Such might be the system of the Gnome at the very same time that the followers of Leibnitz, reasoning on what they saw on the ~uter . .surface, would be teaching the doctrine of gradual refrigeration, and averring that the earth had begun its career as a fiery comet, and would hereafter become a frozen icy mass. The tenets of the schools of the nether and of the upper world would be directly opposed to each other, for both wou~d partake of the prejudices inevitably resulting from the c?ntmual contemplation of one class of phenomena to the exclusion of. another. . Man observes the annual decomposition of crystallme and Igneous rocks, and may sometimes see their conversion into stratified deposits ; but he cannot witness the reconversion of the sedimentary into the crystalline by subterranean fire. He is in the habit of regarding all the sedimentary rocks as more recent than the unstratified, for the same ~cason that we may suppose him to fall into the opposite error tf he ~aw the origin of the igneous class only. It Is only by becoming sensible of our natural disadvantages that we s?~ll be ro~sed to exertion, and prompted to seek out opportumtles of discovering the operations now in progress, such as do not present themselves readily to view, We are called upon, in our researches into the state of the earth, as in ?ur endeavours to comprehend the mechanism of the heavens, to mvent means for overcoming the limited range of our vision. 'Ve are perpetually required to bring, as far as possible, within the sphere of observ~tion, things to which the eye, unassisted by art, could never obtam access. It was not an impossible contingency th. at a.s tronomet·s might have been placed ' at some period ' in a Situation much resembling that in which the geologist seems to stand at present. If the Italians, for example, in the ~arly part of the twelfth century, had discovered at Amalphi, Instead of the pandects of Justinian, some ancient manuscripts filled with astronomical observations relating to a period of ·~hree thousand years, and_ made by some ancient geometers G2 |