available for plants, in an increased proportion. The removal of the crops carries away part of the organic and inorganic constituents of plants, which are not returned in the farm-yard manure. If the cultivated plants confined their rootlets to the soil which has been stirred, this argument would have some weight, but when it is considered that nearly all of the cultivated plants send rootlets into the subsoil, the necessity for deep stirring is less apparent. If it is considered that the action of the carbonic acid conveyed to the soil is to decompose the mineral constituents of the soil, and that these, when rendered soluble, are liable to be washed out of the soil by rain-water, the question of deep stirring assumes a new phase. It is quite possible that certain soils, particularly in wet localities, are deprived of the constituents of plant life in a greater degree by the annual rain-fall, than by the annual cropping. Any one studying the actions of arterial, surface, and underground drainage, particularly during a continued rainfall, will better understand what an amount of fertilizing matter is removed by the rain-water. Rapid running streams and drains remove soluble and insoluble constituents, besides the debris of the soil in a state of suspension. Also, slow-running rivers and estuaries in many parts of the United Kingdon, contain in a state of solution and suspension, the elements of plant life apart from finely comminuted portions of the soil, to an extent which few who have not considered the question, would imagine. In some cases they have been advantageously used to increase the fertility of the soil, by warping and irrigation. Egypt is the most notable example of fertility being maintained by the elements of plants and soils conveyed in the water. The soil of the cultivated portions of Egypt, to which irrigation is applied, has been gradually raised by the somewhat slow process of the Nile. The alluvial deposits on the banks of such outlets of rain-falls, as the Forth and Tay, show what steady causes are in operation, removing from the soil the elements of fertility. Liebig appears not to take this cause into account in his recent work on Modern Agriculture. It is a question which is open to discussion, whether or not the rain-fall conveys soluble and floating elements of vegetable life from the land to the sea in a greater extent than the whole sewerage of towns. Of course, the amount conveyed by the rain-fall depends, not alone on the quantity of rain, nor upon the depth to which the soil is stirred, but mainly on the texture of the soil, and the elevation and incline of the lands. We have little doubt that on the great proportion of the cultivated soils in wet districts in Scotland, the amount of fertilizing elements removed by the rain-water is much greater than that removed by the system of cropping pursued-that is, by a portion of the crop being sold off the farm, and the straw and turnip converted into manure and returned to the soil. It may therefore be held

that the deeper the land is stirred, the application of the elements of fer tility must be increased. There is no doubt that the principle of garden culture applied to the great portion of the cultivated fields, must rest on this basis. There are soils so rich in the elements of fertility, that the comparatively exhausted surface soil can be advantageously replaced by the subsoil; but such soils are very exceptional, and may be safely dismissed as not interfering with the principle we have indicted. The farmer will be most successful who expends capital in improving the manurial condition, rather than by increasing the depth of the soil stirred. With both conditions secured, heavier crops, and of a more uniform character, will be raised; but as his object is mainly profit, it is by obtaining the largest return for his capital employed, and not by raising the heaviest crops, that his object is secured.

In carrying out all operations connected with the cultivation of the soil, the question of profit and loss is the proper standard by which to test every suggestion. At present there is almost a passion in favor of deeper cultivation of the soil. It is therefore wise for farmers to weigh deliberately the pros and cons of the question.

The following enumeration may include a division of soils which, with certain directions observed, it may be found profitable to stir to a greater depth than previously:-Soils naturally deep, whether friable or retentive, which rest on a comparatively retentive subsoil. Perfect drainage is, however, one of the conditions which must be first secured. When deeper stirring is carried out, the amount of manure applied requires to be increased; the increase depending upon the natural fertility of the soil, and the mode of cropping followed. Soils which should not be deeply stirred-light sandy, gravelly, calcareous, peaty, and vegetable soils generally, resting on subsoils of a character similar to the soil. Such soils should only be stirred deeper when substances are applied to improve their texture, such as clay, marl, lime, &c., but the depth to be stirred of the previously undisturbed soil should be inconsiderable at first, and, if deemed necessary, gradually increased. Where the subsoil is very porous, great caution should be used.

Increased manurial application is even more necessary for the profitable cultivation of such soils than those of an argillaceous nature. We may afterwards consider the question of stirring the subsoil, with the view of rendering the cultivation of certain soils more profitable.

EXHAUSTION OF THE SOIL.

I wish to bring before this meeting a few facts which have come under my own observation, which tend to show the necessity of bringing the

light of science to bear upon agriculture, and prove the correctness of the theory, which Dr. Hodges has long sought to impress upon this society, namely, that the soil cannot produce, or build up plants, unless it contains the ingredients of which such plants are composed. The soundness of this opinion is strikingly exemplified in the neighborhood of Loughgall, county Armagh, where the soil belongs to the class of sandy loams, and rests upon a limestone formation. This land was formerly considered by many to be the best in Ireland; indeed, so celebrated was it for fertility, that it was denominated "The Garden of Ireland," and a portion of the district towards Kilmore is still called "The Honey Pot," to indicate its extreme richness. Latterly, however, this once fertile soil has been becoming less productive, and the year 1859, the wheat, in many instances, was comparatively worthless. In 1860 it was a little better, but still infe rior to that in the surrounding districts, which were formerly considered unfit for the production of that valuable cereal.

Having been engaged in the wheat trade myself for more than twenty years, I observed this gradual deterioration in the quality of the grain sent to market from the district in question, and latterly tried to avoid buying any from the neighborhood, believing that the quality could not be good. Observing these things, I became convinced that the soil was being exhausted of some elements necessary for the proper development of plants, and to test the correctness of this conclusion, I procured a sample of the soil upon which inferior wheat had grown, and had it analyzed by Professor Hodges, and the result will show that this once fertile soil—this garden of Ireland-is fast approaching to barrenness, and unless a more skillful mode of husbandry be adopted, it will soon be unfit for profitable cultivation.

Now, by comparing the analysis of the Loughgall soil with that of the barren soil, they will be found to be nearly identical; and by comparing the composition of the Loughgall and the fertile soils, it will be seen that the former is mainly deficient in alkalies and acids, and as the crops generally cultivated contain a large proportion of these deficient ingredients, it is clear that they cannot be perfected without them. Professor Cameron shows that the ashes of the following plants contain, in 100 parts (I only note the ingredients which are deficient in the soil):

Whence, then, are these essential elements to be derived, seeing they are not to be found in the soil Some of them, it is true, may be extracted from the atmosphere in limited quantities; and it is evident that the crops in the district in question, are greatly dependent upon that scanty and precarious supply for their sustenance. For, in the late very dry season of 1859, when there was not sufficient rain to convey from the atmosphere the indispensable ingredients which were not contained in the soil, the wheat mildewed, withered, and died; whereas, in the following year, there was abundance of rain, which carried a partial supply of nutriment to the plants, and prevented them dying of starvation. This, in some degree, accounts for the remarkable fact before referred to, that, in 1859, the wheat in the neighborhood of Loughgall was universally bad, while in the surrounding districts the quality was excellent, although the yield was not very abundant, while the whole country suffered equally from drought.

Professor Johnston shows that a rotation of crops, similar to that alluded to above, carries from the soil

Now these materials have been carted off many farms from year to year, in the shape of potatoes, turnips, wheat, clover and oats, have been but partially restored by a limited application of farm-yard manure; consequently the soil has become exhausted, and its cultivation unprofitable.

The foregoing facts I look upon as practical illustrations of Baron Liebig's theory, and a remarkable fulfillment of his prediction. In the Belfast Mercury of 29th December, 1859, he is reported to have said :-"A child can comprehend that a very productive field, in order to remain very productive, or even simply productive, must have the elements which have been withdrawn in the harvests perfectly restored-that the aggregate of condition must remain in order to produce the aggregate results; and that a well, however deep it may be, which receives no supply of water, must in the end become empty, if its water be constantly pumped out." Again, speaking of the economizing of manure, he says: "It is clear that if these elements were collected without loss, and every year restored to the fields, these would then retain the power to furnish every year to the cities the same quantity of corn. And it is equally clear, that if the fields do not receive these elements, agriculture must cease." In corroboration of this, Professor Hodges says, as reported in the Journal of February, 1860: "Science teaches us that even the more fertile field is not inexhaustable; that the most productive soil contains only a limited amount of the materials which the plant can mould into wheat, or potatoes, or turnips; that every plant grown by the farmer requires at least eight substances to be supplied by the soil for its development. And it follows, that if our farmers, year after year, in their crops and cattle, sift out as it were, mainly five or six of these necessary constituents of the soil, the work of production, after a time, cannot go on." Now, although the members of this society may be quite conversant with the above theory, there are many farmers who are not so. For respecting the great failure of wheat in 1859, I have heard it said by persons from the district in which it occurred, that "there was a shower of honey in that neighborhood which spotted the straw, and the wheat did not fill afterwards." Now, this spotting of the straw was, I think, caused by the want of mineral matters in a soluble state, to give it sufficient stamina. Others say, "the ground is too rich, and sends out too much straw, which lies down, and the wheat does not fill." Now the land may be too rich in some respects, but the analysis shows it is miserably poor in others, and, unless a proper proportion of the deficient elements be supplied, the soil cannot be restored to its former state of fertility. Again, others say, "the land is wheated out and requires rest." And this is probably pretty near the truth, as rest would certainly improve the exhausted land. But resting land is too slow a process for these stirring times-particularly as the landlord and tax-gatherers cannot be induced to rest at the same time, but must have their several demands satisfied. Therefore it is much wiser for farmers to avail themselves of the information afforded by this and similar societies, which will enable them skill