manure, this gradual supply of food of a tolerably complete character will be found to be one element in its nature which has materially aided it in gaining the warm approval of experienced men.

CHAPTER XXVI.

THE important duties discharged by farm-yard manure are further influenced by the care taken in its proper preservation. If during the decomposition which it usually undergoes, any waste be permitted, it is evident that such waste decreases the repayment of the loan of materials received from the land. In some farm-yards we still see black drainage matter flowing away from the manure,— an occurrence which every man of experience knows to be a distinct loss of fertilising matter. The decomposition of farm-yard manure which is so very commonly adopted, is desirable and proper, provided it be rightly regulated. It is a means whereby the vegetable matter becomes altered in its character, and the mineral constituents which have been utilised during the plant's growth are set free from their bondage, in a condition ready for again becoming useful for the growth of some other plant. Much of this mineral matter becomes soluble during the changes which take place in the fermentation, and is in solution in the black streams referred to, this plant-food is often allowed to waste. Such

management rather corresponds with the action of the careless spendthrift than that of one who carefully husbands his resources to repay a loan he has contracted. This, at any rate, is not the way to repay to the soil the plant-food which has been borrowed from it. In all well-constructed farmyards, arrangements are made for conveying all the drainage matter into a tank, or some convenient receiver, from which it is pumped out for use. No portion of the manure should be allowed to waste, for it necessitates the purchase of new supplies to enable the farmer to return to the soil that which he has removed in his crops.

Some farmers have to contend with the disadvantage of large open yards which receive large quantities of rain, and have no conveniences provided for the preservation of this liquid manure. What is a man to do under such circumstances? In the first place let him realise the fact of the loss which he sustains. His position is undoubtedly one of great difficulty, but he gains much by knowing that he is losing fertilising matter, which he must replace in some form or other if he would maintain the land in fertility. Being aware of his loss, he will be sure to do the best he can to get the aid of his landlord to prevent it. No farm can be considered in a tenantable condition whilst such losses are not guarded against, and a suitable tank should be constructed. When the waste has been stopped, he will soon find means for using the liquid manure, and especially by having it pumped

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over his manure heaps from time to time. In some cases, even this use of the liquid will not take all that he is bound to dispose of. He will in such instances see that this arises from the rainfall which reaches his yard being greatly in excess of that which is desirable; he will prudently adopt measures for carrying off as much of the rain-water as possible before it reaches his manure, especially all that falls upon his buildings, and it will ultimately make him value the advantages of properly protected yards. So long, however, as he has to contend with excessive supplies of water, it is probable that the use of such liquid for irrigating land at a lower level will be the best mode of using any superabundant flow of liquid manure not required for the manure heaps.

The care which may be taken for the preservation of farm-yard manure from waste by any addition of water must not be carried to the opposite extreme, so as to lead to the practice of keeping the manure short of its necessary supply of moisture. The adoption of covered manure pits and covered yards, although having many advantages, is still open to the danger of allowing the manure to become too dry. We have noticed the disadvantages arising from an excess of water, and it may be well to point out the losses arising from a deficient supply. It is, as a rule, desirable and necessary that farm-yard manure should undergo a proper fermentation. During the changes which then take place a moderate supply of

water is essentially necessary, for if there should be a deficiency, the manure becomes overheated, or, as it is commonly termed, fire-fanged, which probably means a sort of burning. Looking at the changes from a chemical point of view, we can confirm the popular idea of injury arising from too much heat. We may, however, go beyond this, and point out that the loss which takes place is most serious, in consequence of the escape of ammonia from the manure. Ammonia may be produced in farm-yard manure in two distinct forms. It may be associated or combined with decaying vegetable matters in forms which are known as organic acids; and in this condition, whilst it may be washed away by water, it cannot, at any ordinary temperatures, be drawn away into the air, or, in other words, it is not volatile. If, however, these organic acids have, by reason of a scarcity of water or otherwise, changed into carbonic acid, and have combined with the ammonia in this form, then the ammonia is exceedingly volatile, and passes away into the atmosphere with the greatest freedom. It will therefore be evident that it throws a very serious loss upon the farmer when the ammonia of the farm-yard manure takes this light and volatile form. It then passes beyond his influence and control, becoming about as useful to his neighbours as to himself.

The means whereby the fermentation of farm-yard manure is regulated are exceedingly simple, but at the same time very important. Apart from the

question of the composition of the manure—which we do not here consider—we find that the supply of air and water have very controlling influences upon the rapidity of the fermentation and the character of the products which result therefrom. If air be excluded from the manure, the fermentation is proportionately checked, whereas it is quickened by a proper admission of air. This is commonly recognised in practice, for if we wish to hasten the fermentation we have the manure turned and thrown together lightly in a heap; but if we wish to check the fermentation, horses and carts are allowed to pass over it, so as to compress it as much as possible. In the one case the air is freely admitted, and in the other instance it is excluded. We have a very similar set of circumstances in the case of an ordinary fire; if you desire it to burn more rapidly, it is stirred and poked so as to lighten it, thereby enabling more air to be admitted. If, on the other hand, the desire be to check the fire in its burning, the coals would be kept compactly together, and probably the surface would be covered with small coal to impede as much as possible the passage of air through the fire. In the same way with the farm-yard manure, the rapidity of fermentation is very greatly under control, and it can be hastened or impeded at will. It is very well known that there is a very great difference in the manure from different portions of the live stock, some of which is naturally very slow in fermentation. At first this appears to be an