it is that in its passage through the land any good results can arise. It may not unnaturally be thought probable that any plant-food in the soil would soon be washed out it, and carried away beneath soil, either into drains or into some porous rock beneath. Some thirty years have now elapsed since Professor Way's experiments were published by the Royal Agricultural Society of England, explaining the very important action which takes place in the soil. It was shown by these experiments,1 that "the influence of the water was felt long after it had drained from the land, and that it had left behind it in the soil a rich manuring of those elements which plants delight in." Materials dissolved in water and added to a shallow bed of soil were arrested by the soil during the passage of the water. When that valuable fertiliser sulphate of ammonia was dissolved in water and added to the soil, the water passing from the soil contained sulphate of lime, the soil having secured the most valuable fertiliser and substituted another of less value. A solution of potash had very similar treatment in the soil, and the lesson which it taught was, that water containing fertilising matter was deprived of its more valuable constituents as it passed through the soil, and that these matters were retained in the soil ready for plant-growth. If any base was removed from the soil it was a substitute for some other substance of greater fertilising value.

An important application was soon made of this 1 Journal, Royal Agricultural Society, 1850, page 379.

fact, by water being used as a means for distributing fertilisers over and into the land, instead of doing it by carts and hand labour. Mr. Robert Smith adopted this plan on some of the Exmoor hills on which it was desired to secure a good pasturage, but which needed manure to encourage the growth, and yet they were almost too steep for any application even of light and portable manures. The plan which he adopted was to make use of a spring of water on some high portion of the land, and this was conveyed by water-channels to a convenient spot, so that manures could be added to it as it passed through a large tank. The water was then conveyed away in a small channel having a very slight incline, and thus the water was conveyed around any lower portions of the hill. A small piece of slate was used so as to block the passage whenever it was desired to make the water run over the edge and trickle down the hill, carrying with it the fertilising matter which had been added to it. As one portion of the land was sufficiently watered, so the slate was removed from across the channel, and placed so as to turn the water over another portion of land. Mr. Smith went so far as to make a yard and shedding for stock at this high level, and wash all the fertilising matter out of the manure. It was found a very cheap and valuable means for distributing manure over lands which were difficult to enrich by ordinary means. The value of the arrangement, however, depended entirely upon the power of the soil to separate the fertilising matter dissolved

in it, for if the soil could not have done this, it would have been simply a means of wasting manure, and nothing more. It affords, therefore, a very good illustration of the absorptive power of soils, and the economic use of water as a carrier and distributor of manure.

CHAPTER XLVI.

A VERY curious instance of land irrigation caused much surprise for some time by reason of its apparent contradiction to the views already expressed. In the Journal of the Royal Agricultural Society just referred to, the late Mr. Philip Pusey added a note to Professor Way's Report as follows:-"It is remarkable that Lord Hatherton's meadows are irrigated entirely from drains, the water of which has, therefore, already undergone this very process of filtration before it fertilises the land." The author visited this estate at Teddesley not long after this; doubt had been raised, and the following are the facts of the case as reported1 by him in 1858. "About 200 acres of very wet land situated on the highest portion of the farm at Teddesley had for its improvement and cultivation to be thoroughly drained. In doing so several strong springs were tapped. These when combined produced a permanent and abundant

1 Bath and West of England Agricultural Society's Journal, 1859, page 156.

flow of water. This stream has been conveyed to the farm buildings, where it works a mill-wheel 38 feet in diameter, and gives a power equal to twelve horses. This power is employed for grinding corn and malt, sawing, carpenter's work, chaff-cutting, threshing, and other farm operations. After being used in this manner, it is conveyed away for the purpose of irrigating 120 acres of meadow-land below. The originality of this application of water, which was previously productive of so much injury to the land when stagnant, but is now rendered so valuable as a motive power and for irrigation, is perhaps scarcely equalled. It is now some years since I personally inspected these meadows, but I do not consider the action of this drainage water to be as contradictory as has been represented. It appears to me that the explanation lies in the fact that many fresh springs which had never passed through the soil were conveyed away in the drains, and hence had not come under this influence. Had the entire quantity of drainage water passed through the soil from the surface, very different results would have been seen; but if, as I believe, it arises from the fresh springs drawn off into the drains, the question no longer rests on the absorptive powers of the soil."

Thus far the advantages of irrigation have been traced to the direct addition of fertilising matter, but another influence is often exerted by it, resulting in an artificial climate being produced in the soil.

Much of the water used for irrigation has

a higher temperature than the land through which it passes, and thereby direct warmth is imparted to the soil. We cannot trace any large share of the influence to this cause, but it may still be regarded as one source of warmth to the soil. In fact, cases have been noticed in which the beneficial influences on land decreased as the distance from the spring increased.

Most persons have noticed how freely vegetation is continued through the winter months, when the surface has been protected and shielded by any loose materials lying about on the surface. It was at one time thought to have arisen from the simple fact that these materials simply prevented animals eating the growth, which had been specially observed. This was definitely tested by Mr. Gurney, and the results of his experiments were reported in an article on the "Practice of Irrigation" by the author, published in 1859.1 Mr. Gurney found that if rods of wood, iron, or any other material, were supported within one inch of the surface, an increased growth resulted, and the greater the width of the covering material the more evident was the effect. Flags, rushes, straw, bushes, or any similar covering produced the same effect. Reeds or wheaten straw applied over the grass at the rate of about a load or a load and a half per acre in a very short time increased the quantity of grass to an incredible extent. The various grasses under these coverings were found to be healthy, and rapidly passed through their stages of

1 Bath and West of England Agricultural Society's Journal, vol. vii. page 148.