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sands and gravels are dug and lixiviated on the spot, the liquor evaporated, and the crude salts exported at the rate of many thousand tons per annum.

We have said nothing of artificial manures, whose name is legion, but restricted our notice chiefly to manurial substances which occur native in the crust of the earth. No doubt these substances enter largely into the artificial manures of commerce; but other substances of an organic nature are also employed, taking the manufacture more under the head of Chemical Technology than of Applied Geology. Indeed it is often difficult to say what enters into the composition of many of these artificial manures-ashes, peat-mould, sawdust, gypsum, chalk, salt, sand, loam, and other substances still more worthless and objectionable than the worst of these.

In the preceding paragraphs we have endeavoured to explain, as fully as our limits will permit, the relations that subsist between Geology and Agriculture. Those refer to the soils upon which the farmer has to operate, whether they be soils of disintegration, resulting from and directly affected by the rocks on which they rest-or soils of transport, which have been weathered and wasted from distant rocks and laid down by various agencies in the situations they now occupy. They refer also to the subsoils on which the arable soils rest, and the influence these may exert on their drainage, texture, and fertility. Much of the agricultural surface of Britain consists. of what the farmer terms "made soils "—soils reclaimed from stony bouldery wastes, heathy, peaty moorlands, and plashy swamps and morasses, by blasting and removal of boulders, by turfing and burning, and by draining. But whether reclaimed or natural, soils are not all alike fertile, some being too sandy, too clayey, too peaty, or too calcareous; and the question arises, How far their defects may be remedied by admixture with other soils, so as at once to impart to them the necessary composition and texture? Besides fertile admixture, there also arises the question of drainage, by which the superfluous moisture may be got rid of most effectually, and at the cheapest rate, so as to render the soil drier and mellower, and more easy of cultivation, more friable, and thereby more permeable by air and moisture, and deeper and softer, that the crops may readily extend their rootlets in search of the nourishment they require. As this nourishment or manure is largely obtained from the mineral kingdom, it becomes necessary, in the next place, to advert to the more important of the mineral manures-treating of their geological nature,

their abundance, and the facilities with which they can be obtained. Whether carbonaceous, calcareous, or saline, these mineral manures are yearly assuming a greater importance; hence the value of an intelligent acquaintance with them to the practical agriculturist. Considering, therefore, the nature of soils and subsoils, their composition, texture, and relations to the subjacent rocks; and considering also the importance of drainage, and the application of mineral manures -all of which involve some acquaintance with the materials and structure of the earth-the relations of Geology to Agriculture must be sufficiently obvious and deserving of study alike by the landlord and farmer.

Works which may be consulted.

Johnston's 'Elements of Agricultural Chemistry and Geology;' Stephens's 'Book of the Farm;' Burn's Soils, Manures, and Crops'-Weale's Series; Liebig's 'Agricultural Chemistry;' 'Burat's Géologie Appliquée; Journal of the Royal Agricultural Society;' 'Transactions of the Highland and Agricultural Society.'

D

IV.

GEOLOGY AND LAND VALUATION.

EVERY landed estate has a twofold value-one superficial or agricultural, and depending on the nature of the soil and climate above, another underlying or mineral, and depending on the nature and abundance of the rocks and minerals below. The surface value will vary according as the soil and situation are fitted for general husbandry, for pasture, for forestry, or for sporting purposes. Land valueless for graingrowing may be valuable for pasture, and wide expanses unsuited for either, may bring large prices as game moors and deer forests. Fancy prices may also be given for certain estates, the adjuncts of scenery-wood and water, dell and dingle, cliff and crag-conferring on them an adventitious value; but, generally speaking, the richness of the soil, the geniality of the climate, good roads, and access to markets, are the conditions which determine the price to be paid for the mere land-surface. We here refer to country estates in general, and not to those in the proximity of towns, or contiguous to navigable rivers and harbours, which often bring fabulous prices for building-sites, ship-yards, factories, and other similar purposes.

But beyond this superficial value there is a mineral one, and this will be regulated by the nature of the rocks and ores below, their abundance, the facility with which they can be obtained, and the prospect of continuous or increasing demand. In selling or in purchasing estates, this twofold value should always be held in view; and no factor or estate agent can do justice to his client who is incapable of estimating, or of procuring reliable estimates, at once of the capabilities above, and the resources that lie below. We have known estates sold for the mere agricultural value of their cold, clayey, and retentive soils, without taking into account the bands of ironstone and fire-clay which lay below, and which could have been readily estimated by a competent mineral surveyor, or by a little judicious outlay in trial by boring. We have known others sold

much beyond their value, from the impression that they contained ores of copper and lead, because at certain spots there were traces of old trials for these metals. In either case thousands might have been gained and saved by proper precautions to arrive at some definite estimate of the nature and abundance of the minerals that lay below.

I. SURFACE OR AGRICULTURAL VALUE.

And first, of the surface value, and the mode of estimating it as far as geology is concerned. Having ascertained the nature of the climate, water-supply, condition of roads, access to markets, public burdens, and other accessories, a minute inspection of the soils should be made, their capability of improvement by draining, and their correction by admixture. As stated in the preceding chapter, a map of the superficial accumulations of the district may be consulted with advantage, but this cannot supersede a detailed survey of the soils and subsoils of the estate. One portion may consist of sands, another of peaty earth resting on clay, a third of stiff heavy loam, and a fourth of dry shingly soil resting on the subjacent rock. Are the sands calcareous or simply silicious? Can the heavy loam be rendered drier and lighter by draining and by admixture with the sands? Can the peaty earth be improved in quality and texture by admixture with the clay, or can the peaty surface be conveniently removed, as in the case of BlairDrummond moss, and the clay be exposed as the agricultural surface? Again, as some soils are better suited for certain crops, some for grain, others for green crops-some for pasture, and others for forest growth, a knowledge of these facts may enable one purchaser to offer a price with safety, which would simply stagger another who was incapable of such discernment. These and similar considerations must be weighed and balanced before the value of any estate can be fairly determined; and for this purpose frequent pittings in the soils and subsoils should be made, and the nature of the material methodically ascertained. A few spadefuls to reach the subsoil is all that is required in such pittings; and considering the certainty they confer on the estimates of the valuator, it is astonishing that this mode of determination is not more extensively and systematically adopted.

As the estate stands, it has a certain value which depends upon the rental received; and to one purchaser ignorant of its capabilities, this may determine the price - while to

another acquainted with all its facilities for improvement, a much larger sum may be given, and yet in the long-run it may be a cheap and profitable purchase. The farmer in offering for a new farm is never altogether guided by its existing condition, but looks forward to how much it may be improved during the currency of his lease, by judicious outlay in draining, subsoiling, removal of surface stones, and the like; knowing well that by these means he will not only increase the quantity and quality of its produce, but greatly diminish the cost of cultivation. And so it should be with the purchaser of an estate; he must not be altogether guided by existing appearances, but should consider well how far the property contains within itself, or lies adjacent to, the ready means of permanent improvement. The grazier who gives ten pounds for a growing beast, and pays five for its pasture, may at the end of the season sell it for twenty; and so the purchaser of landed property who gives twenty thousand, and judiciously expends five on its improvement, may in a few years raise its value to thirty thousand.

The Landscape.— Surface Amenity.

Closely connected with the value of the land-surface, is the art of laying it out into fields, parks, and plantations, so as to enhance at once its value and amenity. Few arts require more skill, and observation of nature's aspects, than that of landscape-gardening, not only in improving features which an estate may already possess, but in bringing out new features by judicious planting and enclosing. A domain naturally regular and tame in surface, may be rendered more attractive by the disposition of its woods and the winding lines of its enclosures. Another, naturally more diversified by hill and vale, crag and dell, may have its charms doubly increased by the skilful introduction of wood and water. It is astonishing how much can be done by a little judicious planting and enclosure. A few clumps to break the monotony of a moor, a trail of ivy over a bald brow of rock, a few climbers to mask the face of an old stone quarry, or a sprinkling of shrubs to enliven the slopes of an ordinary road-cutting, will often produce an effect worth ten times the outlay. And as with the minor, so with the major features of a domain,-the tamest may be improved by intelligent treatment. No doubt such dispositions depend very much upon the artistic tastes of the disposer; but there are certain geological connections between trees and soils, woods and crags, rocks and waterfalls, a knowledge of which cannot fail to be of use to the landscape-gardener. Nature

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