of the buildings send down a large proportion of all the rain received in the courts, and they send it down in quantities at a time-a condition which empowers the rain to carry off forcibly a part of the products of the dung. But this result is clearly not attributable to the want of cover to the courts, but the want of spouts to the houses.

2016. But allowing the courts to be, as they generally are, uncovered, and the buildings unsupplied with rain-water spouts, it is still subject for consideration, whether or not the wet dunglitter of the courts should be put under cover, when formed into dunghills, so as to prevent, at the least, the carrying off the products of the dung by the rain that may fall from the time the dunghill is formed until it is used; whether, in short, the covering of dunghills is practicable in the fields? The object of the cover seems to be entirely to prevent, or at least to retard, the fermentation of the dung-heap, So as the gases forming the constituents of the dung shall not be generated and dissipated in the air, but retained in the dung-heap, and, after being ploughed into the soil, evolved only when wanted by the plants. Could a plan be devised which would give so complete a command over the fermentation of the dung-heap, it would be worthy of adoption by all farmers; but is such a result certain? Let us cogitate on all the particulars required to be provided for the adoption of such a plan. It is easy to erect a shed in every field, but, to answer its purpose, it would require to be constructed of a peculiar form, and in a particular manner. If it is desirable to retard the fermentation of the dung-heapand the desire to cover it implies that condition-the heap must be compressed, and there is no means so ready of compressing it, as by the weight of the horses and carts. Now a shed, to afford head-room for the depth of the future dunghill, to take horses and carts under it, should be of considerable height, and would be an expensive structure. Were the dung put under the cover without compression-that is, wheeled in barrows by the cart-loads, as laid down by the carts-the dung would in effect receive a complete turning, and be strongly encouraged to fermentation. To avoid this risk, were the dung retained in the courts until the season arrived when the dung ought to be turned, the dung-litter will have accumulated to an inconvenient height in the courts and hammels. To avoid this inconvenience, and to secure the retardation of the fermentation, were the walls and feeding-troughs of the courts and hammels raised so high as to contain the season's dung, the troughs would be placed inconveniently high for the cattle to reach the turnips in the early part of the feeding season. I think all these conflicting circumstances might.be compromised in this way: Let the dung be taken out of the courts when the frosty weather permits it, and compressed, as at present, by the carts on one of the side-ridges of the field, and, as long as the cold weather continues, there is very little chance of destructive fermentation occurring. Let a shed be erected in the fence of the field, parallel with the side

VOL. I.

ridge of the field, and the dung-heap should be formed along the side of the shed. Let the shed have permanent walls and a permanent roof, and let the sides be made capable of being closed in; and, as to the dimensions of such a shed, suppose the field to be manured contains 25 acres, and allowing 20 cart-loads to the acre, accommodation would require to be made for 500 cubic yards of dung, which contain 13,500 cubic feet.

2017. Now the form of such a shed requires consideration, if we desire to have the manure in its best condition. Mr Rowlandson, of Bootle Village, near Liverpool, has considered this subject practically, and this is his opinion of it:"The fermentation of manure heaps," he observes, "depending upon the presence of heat, moisture, and the atmosphere, the skilful farmer will avail himself of the means in his power to promote or retard fermentation, by dispensing with or admitting one or other of these agents, as the case may require. This is done in several The free admission of the atmo

ways. sphere is one of the principal causes of excess of fermentation; and Boussingault, although he does not state this to be the cause, admits that 'it is of much importance that the heap be pretty solid, in order to prevent too great a rise of temperature, and too rapid a fermentation, which is always injurious. At Bechelbronn, our dung-heap is so firmly trodden down in the course of its accumulation, by the feet of the workmen, that a loaded waggon, drawn by four horses, can be taken across it without very great difficulty.' Notwithstanding what has just been stated, many able writers on the matter have asserted that tramping down manure is injurious. It is obvious that each party is right according to circumstances. If a manure-heap is required almost for immediate use, nothing is more certain than that a free admission of the atmosphere is necessary, in order to promote free and rapid fermentation; but this is done at the expense of a considerable escape of its volatile contents. On the other hand, if intended to lie for some months, as is frequently the case, pressure, and consequent absence of a great portion of atmospheric air, is advantageous, fermentation being by this means retarded, and generally proceeds more equally throughout the

mass.

By restricting the admission of air, we have a direct command over the fermentation of the manure-heap; and this can only be accomplished by placing the manure in pits. If they have a rough covering, so much the better. The usual shape of a manure-heap is that of a cube or parallelopepidon, each being a figure of six sides, five of which are exposed to the influence of the atmosphere, the bottom only not being surrounded by it. By the pit we shall completely reverse the order, one side, the top, only being exposed to the atmosphere; and that is also the side, from the altered circumstances of the heap, into which the air will have the greatest difficulty in penetrating. In fact, from the absence of draught from the sides, fresh volumes of air will only penetrate the top by means of pressure. The best formed manure, in the 2 G

shortest period, that I ever witnessed, was that from the pit belonging to an extensive cart proprietor. In the stable there were usually about thirty horses; the pit was formed in the yard, and covered over with thick planks, part of which was covered over with earth, and paved, only a few boards remaining loose for the convenience of removing the manure, with a trapdoor for the purpose of putting the manure into the pit. The yard was roofed in, so that no extraneous moisture could be admitted-so circumstanced that, in summer, the whole of the mass, except the accumulation of the last few days, was converted into a well-fermented workable state in the course of ten days or a fortnight in winter it took about three weeks to accomplish the same. It might be supposed that serious annoyance would be felt at the escape of ammonia, and that a most extraordinary heat would be generated; but such was not the case. I have been present when such a pit was being emptied, but the heat was not nearly so intense as that frequently observed in ordinary farm-yard heaps; and, unlike the latter, it was not entirely confined to the centre, whilst the sides were comparatively cool, but pervaded the whole mass in an equal degree. No perceptible smell of ammonia was perceived, but a very copious amount of aqueous vapour was evolved in the course of its removal-so much so, that you could not, at times, see the workmen in the pit when removing the manure. Another advantage to be derived by using pits is, that, in winter, the caloric arising from the fermentation of the heap could not be dissipated so speedily as it is under the present system, when surrounded by a cold, perhaps a frosty atmosphere. It is so well known that manure-heaps formed in winter do not ferment equally, or scarcely at all, that it has given rise to the axiom, that one load of manure formed in summer is worth two formed in winter." The last observation is a strong argument against turning dung-heaps in winter, and, of course, in favour of keeping them in a compressed state until a short time before the fermented manure is wanted to be applied to the soil.

*

2018. From what has been stated, and from the circumstances of the case, the construction of a shed for containing the manure-heap, when preparing in the field for laying on the land, should be to have a stone-and-lime wall to support a permanent roof; and, to put the eaves of the roof beyond the reach of the cattle, when grazing in the field in summer, the wall should be 6 feet above the ground. The width of the shed should not be more than what a man can reach across with the graip, when emptying the dung out of it into the carts; and this space may be taken at 10 feet, which width would admit of a cheap roof, in as far as the timber is concerned. To form the shed into a pit, and give scope to fermentation when it is wanted, the dungheap should be fermented at about 9 feet in thickness, which would cause the pit to be 3 feet below the level of the ground. To enable the floor

to keep out water, the shed should be thoroughly drained all round, and the floor should be well puddled to retain the dung water. To contain 13,500 cubic feet of dung in a shed 10 feet wide and 9 feet deep, would require it to be 150 feet in length; but as it would be more convenient to have two sheds, to contain half the quantity at the opposite sides of the field, than the whole quantity in one place, a shed on each side, of 75 feet in length, with the other dimensions given above, would contain all the dung. And, when these sheds were made in the line of the fence, they would be useful to the fields on both sides of them; and, when erected in the angle where 4 fields meet, one shed would serve the purpose of all the fields; and at that point they would be most conveniently placed for using the head-ridges by the carts. A part of the wall in the centre of each side of the shed should be made only 3 feet high and 6 feet wide, to allow the carts to back to and get loaded when the dung was removing to the field. A similar form of shed h' may be seen alongside the figure of the liquidmanure tank k', Plate II.

2019. What I have suggested in regard to the general treatment of the dung-heap seems, therefore, a feasible one-namely, to cart out the dung in winter, and to compress it in a heap by the side of the shed with the carts and horses; and, as the season advances, and the heat may promote fermentation naturally, to wheel the dunghill into the shed to ferment, and where it may be expected to be ready for use in the course of a month or six weeks, according to the temperature of the weather and the material it is composed of, being aware that horse-dung ferments more quickly and actively than cow-dung. The cover of the shed will protect the fermenting mass from rain, and, when the space which allowed the dung to be put into the shed is boarded up, very little free air will find admission into the inside of the shed. Out of such a shed will, of course, cause more trouble to cart away the dung than from the open field; but if the dung is preserved in a better condition in it, the advantage will more than counterbalance the additional expense of taking it out, which is only manual labour.

2020. But it may be remarked, that when the dunghill is left in the air, when first formed from the courts, the rain or snow will find their way through it, and injure the quality of its contents by washing away the soluble portions of the dung. No doubt this may take place to a certain degree; but, as long as there is no active fermentation in a dunghill, and it has been well compressed, and covered on the top with earth, or any other material that would ward off rain, the oozing from it will be very small, and, at all events, the loss will not be great. 66 The amount of my observation," remarks Mr Rowlandson, in the paper quoted above," that in heaps, as usually formed, with free access to the atmosphere, a larger amount of humic acid, soluble in alkalies, is formed than when the

manure is placed in pits, and access of the atmosphere is limited. In the latter case, some humic acid is formed; in both cases, the humic acid is in the same state as that which is found in barren mosses, as I have determined by repeated experiments. The humic acid has a strong affinity to combine with the alkalies, potash, soda, and ammonia, in manure-heaps, and this forms the brown-coloured solution which is observed running from them after rain. It is perfectly obvious, therefore, that every drop of the brown-coloured liquid which oozes from the manure-heap contains, in combination, one or other of the above named alkalies, two of which, potash and ammonia, are of so much importance as fertilisers. The mode I have suggested of placing the manure in pits may be said to remedy this evil, as, at all events, it will prevent the liquid from running away. It is of no importance, however, preserving the liquid of manureheaps in the state described, as I have repeatedly found that no beneficial effects are derived from the use of it." It will be observed that these remarks apply to the dung-heap in a state of fermentation, but, when not fermenting, the dung-heap, in winter, parts with very little liquid; and, by the time it would part with more, it will have been placed in the shed. All oozing would, of course, be prevented, were the dung placed in the shed at once; but it would be too soon fermented, if not tramped down, and it could not be so by men, as Boussingault practises; as such a mode would be too expensive in this country, and not so effectual as with horse and cart; and, what is still more objectionable, the dung so compressed in such a pit could not be turned for fermentation but with inordinate trouble. The first breadth to be turned would have to be thrown and wheeled out, and again wheeled in to fill up the last breadth; and, in the mean time, every breadth would be turned with much inconvenience and loss of time. I am certain the value of all the oozings lost would never compensate for this additional trouble, and the bad work in the turning; and the oozings, after all, are not entirely lost, as the middenstance requires no more manure.

2021. As the subject of dung-pits in fields is new in the husbandry of this country, I shall give a figure of one which I think might answer the purpose in any part of the fence of a single field, or in the point of section of two fences in the corners where four fields meet. Fig. 192 is such a place, where a is the shed, 80 feet long and 12 feet broad, over walls, standing either E. and W., or N. and S., whichever is most convenient for the dung to be brought from the steading to the corners of the four fields, of which bb co are each a fence; dd are the middenstances, 18 feet wide each, upon which the dung is first formed, when taken out of the courts early in winter, but, if towards the end of winter, it should be put into the shed at once; the one stance being for the use of the fields b b, and the other for that of the fields c c. As most of the dung experiences much warmth from a high temperature of the atmosphere, before it is ploughed into the ground, a screen of larch plan

A DUNG-PIT FOR FOUR FIELDS.

protecting the outside of the midden from heavy rains from any quarter in winter; ee are the slip-gates, 10 feet wide, for taking the dung in and out to the fields b b, and ƒƒ those for the fields c c. Of course, the midden-stances dd should be firmly causewayed or macadamised. Such an arrangement, shed, stances, and fences, would occupy a space of 134 feet long by 84 feet broad, or just about a quarter of an acre. The fences of the four fields meet that of the middenstance at the points h; gg is a passage for carts at both ends of the shed.

2022. A rather curious and entirely unlookedfor effect took place from the oozings of dunghills in two fields, on the estate of Pumpherston, near Mid-Calder, in the county of Edinburgh, in March 1848. Tile-drains, that had been made in the autumn preceding, were found to be choked in spring, and bursting out water to the day. On opening them, the tiles within a limited space were completely filled with a peculiar substance. The subsoil in one field was gravelly, and the drains three feet deep; that of the other, clay, with drains of twenty inches deep. In both cases the drains leading from a dunghill were only so affected, and the conclusion arrived at was, that the oozings from the dunghills had induced the growth of the substance found in the tiles. The substance was of a dirty gray colour, slimy, tenacious, some pieces of it resembling fragments of skin, but appearing to consist, when pulled asunder, of minute fibres, too fine to be easily observed by the unassisted eye. It had an extremely offensive, putrid, animal odour, having a distinct resemblance to that of cow-dung. It was impregnated with a good deal of earthy matter which long washing with water could not entirely separate. It was pronounced by Dr Greville, the famed cryptogamist, to be a plant-the Conferva bombycina-the filaments of which are exceedingly fine, and act as a cobweb in catching and, retaining minute insects, larvæ, and floating atoms of inorganic matter in water. These plants grow rapidly, and as rapidly pass into putrescence; and accordingly in this case they had disappeared entirely from the drains in the course of a fortnight

after, when I went to witness the singular phe

nomenon.

2023. No dunghill, therefore, should be formed above tile-drains, for although in this case the alarming state of the drains was but of short duration, more permanent injury may be experienced by other causes. Any how it is safer to avoid such inconveniences, both by placing the dunghills beyond the reach of drains, and also by making the sites of dunghills impervious to liquids. A side-ridge of a field is the safest place, and, when the dung is put into a pit, it is quite out of the way of doing harm.

2024. The dung from a cow-byre placed in a covered pit, direct from the byre, will, I have no doubt, remain a long time, after the arrival of warm temperature, unsusceptible of fermentation; and it is most probably from this property that it has received the character of being a cold manure; whereas horse-dung easily ferments, and goes rapidly through all the stages of fermentation to that of the destructive, which is technically called fire-fanging, and on this account it has received the character of being a hot manure. Both mixed together form a valuable manure, especially when the cow-dung bears the largest proportion.

2025. The hot nature of horse-dung, and its rapidity of fermentation, are supposed partly to arise from its containing more nitrogenous matter than cow-dung; but, according to the analyses afforded by Boussingault, it would seem, at first sight at least, that such an opinion is not wellfounded. The analyses are :

"From these analyses," remarks Professor Johnston," it appears that, though recent cow-dung contains more water than horse-dung, yet the dry matter of the former is richer in nitrogen than that of the latter. Were this generally the case, it ought, one would suppose, after becoming a little drier, to ferment, or be as warm as horse-dung. However this may be, the two circumstances-that the nitrogen of the food is discharged chiefly in the urine, and that the cow voids a much larger quantity of urine than the horse-incline me to believe that cow-dung must generally contain less nitrogen than that of the horse, and that this is really the cause of its greater coldness. The correctness of this opinion can only be tested by a series of careful analyses. At the same time it is proper to add, that the peculiar state of combination in which the nitrogen exists in two bodies, supposing the proportion in both to be the same, may modify very much the rapidity of the decomposition they respectively undergo in the same circumstances."

2026"Though fermenting with such apparent slowness, fresh cow-dung undergoes in forty days a loss of one-fifth of its solid matter, (Gazzeri.) Though this result was observed in Italy, yet there is sufficient loss in our climate also to make it worth the while of an economical farmer to get his cow-dung early in heaps, and to shelter it as much as possible from the sun and air."

2027. "Even when fed on the same food, the dung of the horse should be richer than that of the cow, because of the large quantity of urine the latter animal is in the habit of voiding. In the short period of twenty-four hours, horse-dung heats, and begins to suffer by fermentation. If left in a heap for two or three weeks, scarcely seven-tenths of its original weight will remain. Hence the propriety of early removing it from the stable, and of mixing it as soon as possible with some other material by which the volatile substances given off (much ammonia) may be absorbed and arrested." Here is a strong motive for cleaning out the work-horse stable every day, and of spreading the litter from it over the face of the cattle-court, so as it may be intimately mixed with their litter and dung, and also of tramping a dunghill firmly (2005.)

2028. "Pigs' dung is still colder and less fermentable than that of the cow. ... A specimen examined by Boussingault was found to contain per cent.

Water, Nitrogen,

Recent. Dry. 81.00

2030. An ingenious suggestion has been made by Mr Kirk, Preston Mains, East Lothian, to check the spread of the seeds of weeds amongst manure. His suggestion is founded on the general law of the growth of plants, that certain classes of soils produce certain classes of plants. This law I have endeavoured to illustrate very fully from (382 to 435.) The suggestion is, to put the manure of the straw obtained from one kind of soil on to another. Thus, the straw

obtained from clay soil, that is wheat land, when made into manure, should be applied to light soil —that is, turnip soil; and as, according to this law, natural plants, called by farmers weeds, which thrive upon the clay soil, would not thrive upon the light, it appears to be within the power of the farmer to prevent, or at least to check, the propagation of weeds by seed. Putting this suggestion into practice would be attended with some difficulty; for although Mr Kirk seems to think it is easy 66 to make all the straw grown on one kind of soil into manure by itself," and which, he conceives," might be accomplished with very little additional trouble to the farmer, where several hammels are employed in the feeding of cattle," yet in large courts it would be almost impracticable to prevent the mixture of straw of a stack from clay land with that from light land; and it would be as difficult to devise a plan by which the straw off clay land should be used in the small courts of the hammels, while that from a light soil was in use for litter in the large courts. Besides all this, the best fodder being obtained from light land, the cattle, while using it, could not be littered with straw from clay land, without running the risk of destroying the object in view. The suggestion, however, being founded on correct theory, might be subjected to experiment, which alone can devise a plan for carrying it out into practice. But would it not be better to have the land so clean, as that no seeds of weeds shall be carried from it with the straw of the crops?

2031. Mr John Hannam, in his interesting little memoir on the economy of waste manures, says "Should the farmer be compelled to form a manure-heap in the field, I would advise him by no means to carry it to the field fresh, and to let it decompose there, as is generally the case, before he uses it;" implying that, whenever dunglitter is carried to the field, it must necessarily decompose there. This is by no means a necessary consequence, as it is nearly impossible for fresh dung-litter to ferment anywhere in winter, when tramped hard with carts and horses. Were it shaken up loose and moistened, in order to encourage fermentation with the first increase of atmospheric temperature, a slight decomposition might soon be induced, which would afterwards become active; but such a result would not occur if the dung were compressed into a firm state by adequate means.

2032. He further advises, "before he takes it from the couch, he should have it nearly as rotten as he wishes it to be. He should wet it well with the drainings, and, when he carries it to the field, cover it up with road scrapings, earth, &c. At the bottom of the heap, too, there should be a good bed of earthy matter laid. In this way the manure will come out for use almost as fresh as when put in, the atmosphere having had no access, and the earth at the bottom and on the top absorbing the liquid and gaseous matters that would otherwise have escaped." Without dwelling upon the inconsistency involved

in the instruction, that "before he takes it from the couch, he should have it nearly as rotten as he wishes it to be," with the assertion that "when he carries it to the field, covers it up with road-scrapings, earth, &c., the manure will come out for use almost as fresh as when put in, the atmosphere having had no access, &c.," only conceive the labour implied in all this treatment of the manure, and consider how the horses and men are to accomplish it in the course of a season. There is first the taking the dung from the courts, the byres, and the hammels, to the shed at the liquid-manure tank, there to be well watered with the drainings, and fermented so as to be as rotten as is desirable; then the carting to the field in which it is to be used, and there made into a heap, not upon the ground as it is, but upon a previously constructed "good bed of earthy matter," which of course must have been brought into the field; for if made of its own soil, no advantage would accrue to the field; and lastly, the dung has to be laid on the field. On the supposition that all the dung of a farm is to be treated in this manner before it is considered ready for use, the extent of shed-room at the liquid-manure tank must be very great, and the supply of liquid manure to "well water" such a mass of dung very large; but when the men and horses are to find time to cart out thrice all the dung thus treated before it is laid upon the land, is more than I can conjecture.

2033. Mr Hannam thus expresses his strictures on the treatment the farm-yard manure usually receives from the hands of farmers:-" Again, is it an uncommon case for us to see hundreds of tons of rich farm manure, and vegetable matter, undergoing rapid decomposition in the fields, and so exposed to the alternations of weatherto the storms of winter, and the sun and showers of spring-that the principal portion of the liquid and gaseous fertilisers it contains must run or fly away' before the manure is used?" Surely this is the language of exaggeration, for no rapid decomposition" can take place in dung among "the storms of winter;" and as few "gaseous fertilisers" can "fly away" in" the sun and showers of spring," the heat of early summer being required to produce either result in a mass constituted as farm-yard manure generally is; and as to "the principal portion of the liquid" running away" "in the fields," the earth that receives it will surely derive as much benefit from it, as the "bed of earthy matter" below the heap, and the "road-scrapings" above it, both recommended to be formed to receive this very liquid.

2034. Strictures apply with more truth, and will come more forcibly home, and likely be more attended to, when thus expressed,-" How seldom are the stores of vegetable, animal, and other matters useful to vegetation, which observation may discover and industry collect on many farms, made use of." +