A GEOLOGICAL CENTENARY.
9'HE slow development of that ordered knowledge which
we call science affords one of the most interesting chapters in the history of human evolution. One section of this chapter has been illustrated this week, when London has been celebrating the centenary of the foundation of the Geo- logical Society. The international character which was given to this affair by the presence of delegates with addresses of congratulation froni learned societies in all parts of the world bears witness to its importance. There is, perhaps, no other
ease in *MA the rite of a great SCietiee May be so directly traced to the labelirs Of a single brilly of tlieti. It is to the (Relit-kat 8ociety of London, as Professor dregory pointed Ont in his addreas to the British AsSoCiation at Leicester, that IS dud " the tonversien of geology from a fanciful speculation to an Ordered science." Sir Archibald Geikie, who bi not only the Pi-eaident of the Geological Society, but the incist faitions of liting British geologists, delivered an addresa at the centenary Meeting on Thursday iii which he sketched the position of geulogy A hundred years ago with all his well-knoWn grace of language and hididity of exposition. We are all keenly interested in geology, the science of the planet on Which We live, with it wonderful story of the ithriftenSe tigt and plautestple development of the earth and its inhabitants, std the narrative of its establishment is Well worthy Of a hearing. In a sense, geology is one of the oldest Of scienceS. lfati cohld hardly live on the earth at all Without asking hitnself, as soon as he began to think about his environment, how it had aeqUired its present shape and condition. The interpretation of Nature, as we know from the ancient eosmogonies and creation-myths which have been handed doWn to iis by the earliest Civilisations, was one of the first subjects on VAlich the budding mind of than loved to exercise itself. The elemental forces of the world, with their effects in the distribution of land and sea, as Sir Archibald Geikie ha§ well said, cannot have failed to excite the imagina- tion and stimulate the curiosity of primitive man. "Wind and lightning, rainstorms and river-floods, breakers and tidal- Waves, earthquakes and volcanoes, would seed a to be direct and visible niatifestationd of powerful but thseen supernatural beings. Nor Would the More obtrusive features of land- soaps fail to add their influence,—mountains With their clouds, tempesta, and landslip6; crags and precipices with their strange, grotesque, half-human shapes ; ravines ivith their gloomy cliffs and yawning chasms betWeen." The classical poets and philosophers have preserved for us the speculations by which men in the dawn of science endeavoured to eiplain the features of the earth. In some respects they snoceeded in hitting upon great truths. Pythagoras, as reported in the verse of Ovid, sets forth the doctrine which our great modern poet both:rived from the geologists of the nineteenth century :— " There rolls the deep where grew the tree. 0 earth, what changes hast thou seen!
There where the long street roars, hath been The stillness of the central sea."
But, as A rule, ancient geology was merely fanciful. The aid of a god was invoked to explain all that seemed above the Comprehension of man—as Poseidon was credited with opening the defile of Tempe in order to drain the waters of the inland lake which once covered the Thessalian plain—and so long ail this was the case science was bound to stand still.
The philosophers of the Middle Ages carried geology no farther than the Greeks. In some respects they even dis- played a retrograde tendency. The great controversy about the existence of fossils supplies a case in point. The Greeks had recognised freely enough that rocks which contained the relies of marine organisms mnst have been laid down by the sea, and that this implied a very different distribution of land and ocean as having existed at some very remote period. tut the mediaeval desire to fit science into the accented Mosaic Chronology forbade the acceptance of the great age which must be ascribed to the earth on this theory. So the most absurd explanations of the foSsils were put forward in all sincerity. It *as held that they were mere mineral cot- Cietions, lusus noturae, which simulated the organic forms of living treatures, much as the patterns made by frost on the window-pane simulate plant-forms. Ellen within the nineteenth century a learned divine of the University of Oxford openly avowed his belief that the fossils in the rocks had been purposely placed there by the Devil in order to mislead and perplex human inquirers. It was not until the eighteenth century brought its great contribution of free inquiry to help iii the Unbinding of the chains which had long fettered the human intellect that geology began to develop along the true lines. Even then, it was one of the last sciences to free itself from the hindrances of a priori or metaphysieal treatment. The actual cause which con- tributed to the foundation of the Geological Society was the disgust raised in the minds of a few students by the endless controversies as to the causes of earth-iiioulding iii.which the inner conscionsileas of the writer was taken as a suffiaient measure of facts, and geology had become almost as seetarian and as violent as theology itself. At the end of the eighteenth Century the geological world was almost wholly given up to a heated contest over the rival theories of the Plutonists and the Neptunists, who respectively regarded fire and water as the true "elements "—in the mediaeval sense—from which the earth had taken its being. A considerable library might be filled with the polemical tracts and solid volumes which then issued from the studies of the adherents of either theory; whereas the contemporary contributions to the actual study of geological facts might be contained in a very modest bookcase. It is the eternal glory of a few Englishmen —Greenough, Phillips, and Sir Humphry Davy among them— that they saw the impossibility of thus attaining any valuable results. In the informal way so characteristic of the English mind, they determined to club together in order to try to bring geology in this country back to the true path, indicated in the fine passage from Bacon which they took as their motto, and which invited the co-operation of all students of the earth who aspired "not so much to cling to and use past discoveries, but to penetrate to what was beyond them—not to conquer Nature by talk, but by toil—in short, not to have elegant and plausible theories, but to gain sure and demon- strable knowledge." At first they were content to dine together once a month, and report progress along these lines ; but soon the new idea became so fruitful that the Geological Society was formally constituted, and began that admirable career which for a century has dominated the history of geological study throughout the world.
It must be not supposed that the Geological Society claims to have inaugurated the study of geology on a truly scientific basis; it merely attempted with success to recall men's minds from the bewildering controversies which had been substituted by Werner and his contemporaries for the study of Nature. Already in 1807 the foundations of modern geology had been laid. It is to the genius of James Hutton, of Edinburgh, that we owe the first clear statement of the fundamental doctrine on which all later study of the earth has reposed. The neighbourhood of Edinburgh presents remarkable oppor- tunities for the practical geologist, and in the course of his walks by Arthur's Seat and the Water of Leith Hutton was led to the epoch-making—though so simple—discovery that the agents of geological change in the past were still at work in moulding the earth's surface. Before him it had been taken for granted that the great changes in our planet, which were apparent to all who did not wilfully shut their eyes to the evidence for them, had been caused by violent agencies and great secular catastrophes which were never likely to recur, and at whose nature we could only guess. Poseidon and Hercules were no longer invoked, but comets and deluges and wonderful changes in the direction of the earth's axis of revolution replaced them. Hutton was the first to point out that, when a Scottish stream could be seen any day carrying down debris to the sea and deepening its channel by a few inches, it was not necessary to imagine some vast earthquake which bad split the land into the gigantic ravines and callous of great rivers. In the same way, he showed that the existing agents of geological change were amply adequate to account for the greatest alterations in the surface of the earth, if they were allowed sufficient time to operate. This doctrine, after- wards expanded by Sir Charles Lyell—another Scotsman— into the theory of Uniformitarianism, was the true beginning of modern physical geology, which could make no progress until. it was accepted. That it was universally accepted is mainly due to the labours and ideals of the Geological Society, which, as Professor Gregory puts it, laid the broad foundation of modern geological study by its resolute rejection of the temptation to wander in dreamland, and its steady insistence on the immediate study of Nature as the sole means of advancing science.
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