a study of geology. It may be quite true that high-farming and most remunerative farming have been conducted without any acquaintance with geological deductions; but surely the man who knows the rock-structure of his district, and how this may affect the composition, the retentive or absorbent nature, of the soils and subsoils with which he has to deal, has a power at his command which cannot be employed by his less-informed neighbour. The choice of an eligible farm, drainage, mixing and ameliorating soils, the facility of obtaining lime, marl, and other mineral manures, must ever be peculiarly aided by some knowledge of geology; and he in possession of this will ever have-other things being equal-the better chance of success. And what to the mere farmer will ever prove an advantage, becomes indispensable to the land agent and valuator. No estate can now be fairly valued, either for sale or for farming, without taking into account its mineral resources; and though the agriculturist may obtain this information through the mineral surveyor or geologist, yet some acquaintance with the science must enable him the better to appreciate these reports, and to shape his own estimates for the behoof of his employer. We have known an estate in Fifeshire sold for thirty years' purchase of the rental of its poor, sterile, clayey surface, and which, for the outlay of some twenty or thirty guineas in a mineral survey, would have readily brought three times the price to its stupid and ill-advised proprietor.

And if to the farmer and land agent at home a knowledge of geology be of advantage, much more must it be to the emigrant and settler in a new country. He has to make his choice not only of soil and situation, but of mineral wealth below; and what may be uninviting in the landscape and soil, may be more than compensated by the treasures that lie beneath. Indeed, to no one can a scantling of geology be of greater service than to the settler in a new country;

and scarcely one of those who have made land purchases in America, in Australia, or New Zealand, but continue to regret that they had not been in some measure acquainted with the science. Even the officers of our army, the traveller for pleasure, and the sportsman in search of adventure, each and all admit the want they have felt, and the chances they have missed, from their ignorance of mineralogy and geology. The discovery of a new plant or of a new animal may be an acquisition to science, without being of any economical importance, but it rarely happens that the discovery of new mineral fields is not a gain alike to science and to industry.

To the landscape gardener and artist a knowledge of geology and its relations to scenery cannot fail to be of value. On the rocks and soils of a district depend its capabilities for improvement; and without a knowledge of this connection there can be no judicious laying out of estates, planting of woods, and otherwise adding to the beauty and amenity of a situation. The rocks of a country form the framework and basis of its scenery; its hills, its crags and precipices, its glens and ravines, its sea-cliffs, bays, and promontories, all taking their aspects and hues from their structure, the manner in which they yield to the weather, and other physical characteristics. A knowledge of anatomy is not more necessary to the animal-painter, than a knowledge of geology is to the painter of the landscape; and though landscapes of undying grandeur and beauty have been painted without any special acquaintance with geology, yet will such knowledge be of service to the ordinary artist, and serve to heighten still more the productions of genius.

Such is a hasty glance at some of the more obvious bearings of Geology-bearings which, whether scientific or practical, would require a volume for their full and satisfactory ex

plication. To such professions as we have alluded-mining engineer, builder, civil engineer, farmer, settler, landscape gardener and painter-it requires little effort to see how closely the science bears on these pursuits, and how greatly they would be assisted by some acquaintance with its leading deductions. But, independently of this more immediate and economic value, the science of geology has many claims to its study, even by those who may never be called upon to apply it. As the history of our world, through all its phases of time, change, and progress, it must ever have charms for the educated intellect; a healthful and exhilarating pursuit, whose objects are scattered everywhere beneath and around us; a study whose objects are open at all seasons; and a science whose problems are graven on every feature of the landscape-hill and valley, lake and river, crag and gorge, beetling sea-cliff, and sandy shore.

Nor do its intellectual attractions as a main branch of natural science constitute its sole attractions. Its bearings on other departments of knowledge, its startling speculations and bold generalisations, can never fail to secure the interest of the cultivated intellect; nor least the bearings of these generalisations on modern thought in all that appertains to new notions of time, immutability of law, continuity and progress, and other themes that are gradually widening the restricted boundaries of olden belief, and giving a more catholic impulse to human aims and to human aspirations. And if all this, or even less than this, can be ascribed to geology during its brief cultivation of little more than half a century, what, we may presume to ask, will be the influence of its teachings during the remaining portion of the century that lies before us?

THE NATURE OF GEOLOGICAL EVIDENCE,

THE increasing number of intelligent minds now devoting themselves to geological pursuits is evidence sufficient that the objects of the science, and the methods by which its cultivators seek to obtain them, are more and more meeting with appreciation and approval. Notwithstanding all this success, we not unfrequently hear from the outside misrepresentations of geology, and undervaluing of its results, as if its aim was to unsettle old beliefs without establishing more rational in their stead, and its deductions were illogical and uncertain. That views which run counter to long-cherished and popular opinions should be received with caution and hesitancy is only what geologists, in the prosecution of their inquiries, may expect; but it is no honest reason why their science should be misrepresented or its advocacy traduced.

What we propose, therefore, on the present occasion is, to direct attention to the nature of geological evidence; to show that, when the observations of our science are competently made, they furnish the most reliable of all testimony; to prove that its leading deductions must be accepted as demonstrations; and to insist that any refusal of these must arise either from incapacity to comprehend,

or from an untruthful and wilful resistance to conviction. At the outset, it must be admitted that the assertions of geology, often startling and at variance with popular beliefs, demand the most critical scrutiny. When a science tells, in opposition to what has been taught for ages, that this earth is of unknown antiquity; that its existing seas and lands were not the seas and lands of former epochs, any more than they will be the continents and oceans of the future; that existing plants and animals are not the same as those that lived in bygone periods; that there has been a gradual ascent in time from lower to higher forms; that all life is bound together by a common plan of evolution; that man himself partakes of this plan, and has been an inhabitant of the globe for untold centuries;—when a science makes these and similar averments, we admit that it is but reasonable its doctrines should be received with hesitancy, and submitted to the most searching investigation. If, however, these averments are made in good faith, and have been logically deduced from correct observation, there is no getting over them, however much they may differ from our preconceptions, and we are bound to admit them into the category of our rational convictions.

Of course, in all our reasonings respecting the past, we must be guided by our knowledge of the present, and by faith in the even uniformity and continuity of the operations of nature. We must believe, for instance, that frosts disintegrated, winds blew, rains fell, rivers eroded, waves wasted, and currents transported, in time past precisely as they do now; and that heat, light, moisture, and other climatic conditions, exerted their influence on plants and animals in the remotest ages of the world in the same manner, and with the same results, as they do at the present moment. This belief lies at the foundation of all our reasonings. The whole argument of our science proceeds upon