By the word acidity is conveyed the idea of something hurtful to plants. This something is, doubtless, in many cases, the salts of iron we have just noticed. In others, it is simply the inertness, "coldness" of the peat, which is not positively injurious, but is, for a time at least, of no benefit to the soil.

c. Resinous matters are mentioned by various writers as injurious ingredients of peat, but I find no evidence that this notion is well-founded. The peat or muck formed from the decay of resinous wood and leaves does not appear to be injurious, and the amount of resin in peat is exceedingly small.

3.—The Preparation of Peat for Agricultural use.

a. Excavation.—As to the time and manner of getting out peat, the circumstances of each case must determine. I only venture here to offer a few hints on this subject, which belongs so exclusively to the farm. The month of August is generally the appropriate time for throwing up peat, as then the swamps are usually most free from water, and most accessible to men and teams; but peat is often dug to best advantage in the winter, not only on account of the cheapness of labor, and from there being less hurry with other matters on the farm at that season, but also, because the freezing and thawing of the peat that is thrown out, greatly aid to disintegrate it and prepare it for use.

A correspondent of The Homestead, signing himself "Commentator," has given directions for getting out peat that are well worth the attention of farmers. He says:—

"The composting of muck and peat, with our stable and barn-yard manures, is surely destined to become one of the most important items in farm management throughout all the older States at least. One of the difficulties which lie in the way, is the first removal of the muck from its low and generally watery bed; to facilitate this, in many locations, it is less expensive to dry it before carting, by beginning an excavation at the border of the marsh in autumn, sufficiently wide for a cart path, throwing the muck out upon the surface on each side, and on a floor of boards or planks, to prevent it from absorbing moisture from the wet ground beneath; this broad ditch to be carried a sufficient length and depth to obtain the requisite quantity of muck. Thus thrown out, the two piles are now in a convenient form to be covered with boards, and, if properly done, the muck kept covered till the succeeding autumn, will be found to be dry and light, and in some cases may be carted away on the surface, or it may be best to let it remain a few months longer until the bottom of the ditch has become sufficiently frozen to bear a team; it can then be more easily loaded upon a sled or sleigh, and drawn to the yards and barn. In other localities, and where large quantities are wanted, and it lies deep, a sort of wooden railroad and inclined plane can be constructed by means of a plank track for the wheels of the cart to run upon, the team walking between these planks, and if the vehicle is inclined to 'run off the track,' it may usually be prevented by scantlings, say four inches thick, nailed upon one of the tracks on each side of the place where the wheel should run. Two or more teams and carts may now be employed, returning into the excavation outside of this track. As the work progresses, the track can be extended at both ends, and by continuing or increasing the inclination at the upper end, a large and high pile may be made, and if kept dry, will answer for years for composting, and can be easily drawn to the barn at any time."

b. Exposure, weathering, or seasoning of peat.—In some cases, the chief or only use of exposing the thrown-up peat to the action of the air and weather during several months or a whole year, is to rid it of the great amount of water which adheres to it, and thus reduce its bulk and weight previous to cartage.

The general effect of exposure as indicated by my analyses, is to reduce the amount of matter soluble in water, and cause peats to approach in this respect a fertile soil, so that instead of containing 2, 4, or 6 per cent. of substances soluble in water, as at first, they are brought to contain but one-half these amounts, or even less. This change, however, goes on so rapidly after peat is mingled with the soil, that previous exposure on this account is rarely necessary, and most peats might be used perfectly fresh but for the difficulty often experienced, of reducing them to such a state of division as to admit of proper mixture with the soil.

The coherent peats which may be cut out in tough blocks, must be weathered, in order that the fibres of moss or grass-roots, which give them their consistency, may be decomposed or broken to an extent admitting of easy pulverization by the instruments of tillage.

The subjection of fresh and wet peat to frost, speedily destroys its coherence and reduces it to the proper state of pulverization. For this reason, fibrous peat should be exposed when wet to winter weather.

Another advantage of exposure is, to bring the peat into a state of more active chemical change. Peat, of the deeper denser sorts, is generally too inert ("sour," cold) to be directly useful to the plant. By exposure to the air it appears gradually to acquire the properties of the humus of the soil, or of stable manure, which are vegetable matters, altered by the same exposure. It appears to become more readily oxidable, more active, chemically, and thus more capable of exciting or rather aiding vegetable growth, which, so far as the soil is concerned, is the result of chemical activities.

Account has been already given of certain peats, which, used fresh, are accounted equal or nearly equal to stable manure. Others have come under the writer's notice, which have had little immediate effect when used before seasoning.

Mr. J. H. Stanwood says of a peat, from Colebrook, Conn., that it "has been used to some extent as a top-dressing for grass and other crops with satisfactory results, although no particular benefit was noticeable during the first year. After that, the effects might be seen for a number of years."

Rev. Wm. Clift observes, concerning a salt peat, from Stonington, Conn.:—"It has not been used fresh; is too acid; even potatoes do not yield well in it the first season, without manure."

The nature of the chemical changes induced by weathering, is to some extent understood so far as the nitrogen, the most important fertilizing element, is concerned. The nitrogen of peat, as we have seen, is mostly inert, a small portion of it only, existing in a soluble or available form. By weathering, portions of this nitrogen become converted into nitric acid. This action goes on at the surface of the heap, where it is most fully exposed to the air. Below, where the peat is more moist, ammonia is formed, perhaps simply by the reduction of nitric acid—not unlikely also, by the transformation of inert nitrogen. On referring to the analyses given on page 44, it is seen, that the first two samples contain but little ammonia and no nitric acid. Though it is not stated what was the condition of these peats, it is probable they had not been weathered. The other four samples were weathered, and the weathering had been the more effectual from the large admixture of sand with them. They yielded to the analyst very considerable quantities of ammonia and nitrates.

When a peat contains sulphate of protoxide of iron, or soluble organic salts of iron, to an injurious extent, these may be converted into other insoluble and innocuous bodies, by a sufficient exposure to the air. Sulphate of protoxide of iron is thus changed into sulphate of peroxide of iron, which is insoluble, and can therefore exert no hurtful effect on vegetation, while the soluble organic bodies of peat are oxydized and either converted into carbonic acid gas, carbonate of ammonia and water, or else made insoluble.

It is not probable, however, that merely throwing up a well characterized vitriol-peat into heaps, and exposing it thus imperfectly to the atmosphere, is sufficient to correct its bad qualities. Such peats need the addition of some alkaline body, as ammonia, lime, or potash, to render them salutary fertilizers.

c. This brings us to the subject of composting, which appears to be the best means of taking full advantage of all the good qualities of peat, and of obviating or neutralizing the ill results that might follow the use of some raw peats, either from a peculiarity in their composition, (soluble organic compounds of iron, sulphate of protoxide of iron,) or from too great indestructibility. The chemical changes (oxidation of iron and organic acids), which prepare the inert or even hurtful ingredients of peat to minister to the support of vegetation, take place most rapidly in presence of certain other substances.

The substances which rapidly induce chemical change in peats, are of two kinds, viz.: 1.—animal or vegetable matters that are highly susceptible to alteration and decay, and 2.—alkalies, either ammonia coming from the decomposition of animal matters, or lime, potash and soda.

A great variety of matters may of course be employed for making or mixing with peat composts; but there are comparatively few which allow of extensive and economical use, and our notice will be confined to these.

First of all, the composting of peat with animal manures deserves attention. Its advantages may be summed up in two statements.

1.—It is an easy and perfect method of economizing all such manures, even those kinds most liable to loss by fermentation, as night soil and horse dung; and,

2.—It develops most fully and speedily the inert fertilizing qualities of the peat itself.

Without attempting any explanation of the changes undergone by a peat and manure compost, further than to say that the fermentation which begins in the manure extends to and involves the peat, reducing the whole nearly, if not exactly, to the condition of well-rotted dung, and that in this process the peat effectually prevents the loss of nitrogen as ammonia,—I may appropriately give the practical experience of farmers who have proved in the most conclusive manner how profitable it is to devote a share of time and labor to the manufacture of this kind of compost.

Preparation of Composts with Stable Manure.—The best plan of composting is to have a water tight trench, four inches deep and twenty inches wide, constructed in the stable floor, immediately behind the cattle, and every morning put a bushel-basketful of muck behind each animal. In this way the urine is perfectly absorbed by the muck, while the warmth of the freshly voided excrements so facilitates the fermentative process, that, according to Mr. F. Holbrook, Brattleboro, Vt., who has described this method, much more muck can thus be well prepared for use in the spring, than by any of the ordinary modes of composting. When the dung and muck are removed from the stable, they should be well intermixed, and as fast as the compost is prepared, it should be put into a compact heap, and covered with a layer of muck several inches thick. It will then hardly require any shelter if used in the spring.

If the peat be sufficiently dry and powdery, or free from tough lumps, it may usefully serve as bedding, or litter for horses and cattle, as it absorbs the urine, and is sufficiently mixed with the dung in the operation of cleaning the stable. It is especially good in the pig-pen, where the animals themselves work over the compost in the most thorough manner, especially if a few kernels of corn be occasionally scattered upon it.

Mr. Edwin Hoyt, of New Canaan, Conn., writes:—"Our horse stables are constructed with a movable floor and pit beneath, which holds 20 loads of muck of 25 bushels per load. Spring and fall, this pit is filled with fresh muck, which receives all the urine of the horses, and being occasionally worked over and mixed, furnishes us annually with 40 loads of the most valuable manure."

"Our stables are sprinkled with muck every morning, at the rate of one bushel per stall, and the smell of ammonia, etc., so offensive in most stables, is never perceived in ours. Not only are the stables kept sweet, but the ammonia is saved by this procedure."

When it is preferred to make the compost out of doors, the plan generally followed is to lay down a bed of weathered peat, say eight to twelve inches thick; cover this with a layer of stable dung, of four to eight inches; put on another stratum of peat, and so, until a heap of three to four feet is built up. The heap may be six to eight feet wide, and indefinitely long. It should be finished with a thick coating of peat, and the manure should be covered as fast as brought out.

The proportions of manure and peat should vary somewhat according to their quality and characters. Strawy manure, or that from milch-cows, will "ferment" less peat than clear dung, especially when the latter is made by horses or highly fed animals. Some kinds of peat heat much easier than others. There are peats which will ferment of themselves in warm moist weather—even in the bog, giving off ammonia in perceptible though small amount. Experience is the only certain guide as to the relative quantities to be employed, various proportions from one to five of peat for one of manure, by bulk, being used.

When the land is light and needs amending, as regards its retentive power, it is best to make the quantity of peat as large as can be thoroughly fermented by the manure.

The making of a high heap, and the keeping it trim and in shape, is a matter requiring more labor than is generally necessary. Mr. J. H. Stanwood, of Colebrook, Conn., writes me:—

"My method of composting is as follows: I draw my muck to the barn-yard, placing the loads as near together as I can tip them from the cart. Upon this I spread whatever manure I have at hand, and mix with the feet of the cattle, and heap up with a scraper."

Peat may be advantageously used to save from waste the droppings of the yard.

Mr. Edwin Hoyt, of New Canaan, Conn., says:—"We use muck largely in our barn-yards, and after it becomes thoroughly saturated and intermixed with the droppings of the stock, it is piled up to ferment, and the yard is covered again with fresh muck."

Mr. N. Hart, Jr., of West Cornwall, Conn., writes:—"In the use of muck we proceed as follows: Soon after haying we throw up enough for a year's use, or several hundred loads. In the fall, the summer's accumulation in hog-pens and barn cellars is spread upon the mowing grounds, and a liberal supply of muck carted in and spread in the bottoms of the cellars, ready for the season for stabling cattle. When this is well saturated with the drippings of the stables, a new supply is added. The accumulation of the winter is usually applied to the land for the corn crop, except the finer portion, which is used to top-dress meadow land. A new supply is then drawn in for the swine to work up. This is added to from time to time, and as the swine are fed on whey, they will convert a large quantity into valuable manure for top-dressing mowing land."

A difference of opinion exists as to the treatment of the compost. Some hold it indifferent whether the peat and manure are mixed, or put in layers when the composting begins. Others assert, that the fermentation proceeds better when the ingredients are stratified. Some direct, that the compost should not be stirred. The general testimony is, that mixture, at the outset, is as effectual as putting up in layers; but, if the manure be strawy, it is, of course, difficult or impracticable to mix at first. Opinion also preponderates in favor of stirring, during or after the fermentation.

Mr. Hoyt remarks:—"We are convinced, that the oftener a compost pile of yard manure and muck is worked over after fermenting, the better. We work it over and add to it a little more muck and other material, and the air being thus allowed to penetrate it, a new fermentation or heating takes place, rendering it more decomposable and valuable."

Rev. Wm. Clift, writes:—"Three or four loads of muck to one of stable manure, put together in the fall or winter in alternate layers, forked over twice before spreading and plowing in, may represent the method of composting."

Mr. Adams White, of Brooklyn, Conn., proceeds in a different manner. He says:—"In composting, 20 loads are drawn on to upland in September, and thrown up in a long pile. Early in the spring 20 loads of stable manure are laid along side, and covered with the muck. As soon as it has heated moderately, the whole is forked over and well mixed."

Those who have practiced making peat composts with their yard, stable, and pen manure, almost invariably find them highly satisfactory in use, especially upon light soils.

A number of years ago, I saw a large pile of compost in the farm-yard of Mr. Pond, of Milford, Conn., and witnessed its effect as applied by that gentleman to a field of sixteen acres of fine gravelly or coarse sandy soil. The soil, from having a light color and excessive porosity, had become dark, unctuous, and retentive of moisture, so that during the drouth of 1856, the crops on this field were good and continued to flourish, while on the contiguous land they were dried up and nearly ruined. This compost was made from a light muck, that contained but three per cent. of ash (more than half of which was sand), and but 1.2 per cent. of nitrogen, in the air-dry state—(twenty per cent. of water). Three loads of this muck were used to one of stable manure.

Here follow some estimates of the value of this compost by practical men. They are given to show that older statements, to the same effect, cannot be regarded as exaggerated.

Mr. J. H. Stanwood, of Colebrook, Conn., says:—"Experiments made by myself, have confirmed me in the opinion that a compost of equal parts of muck and stable manure is equal to the same quantity of stable manure."

Mr. Daniel Buck, Jr., of Poquonock, Conn., remarks:—"8 loads of muck and 4 of manure in compost, when properly forked over, are equal to 12 loads of barn-yard manure on sandy soil."

Rev. Wm. Clift, of Stonington, Conn., writes:—"I consider a compost made of one load of stable manure and three of muck, equal in value to four loads of yard manure."

Mr. N. Hart, Jr., of West Cornwall, Conn., observes of a peat sent by him for analysis:—"We formerly composted it in the yard with stable manure, but have remodeled our stables, and now use it as an absorbent and to increase the bulk of manure to double its original quantity. We consider the mixture more valuable than the same quantity of stable manure." Again, "so successful has been the use of it, that we could hardly carry on our farming operations without it."

Mr. Adams White, of Brooklyn, Conn., states:—"The compost of equal bulks of muck and stable manure, has been used for corn (with plaster in the hill,) on dry sandy soil to great advantage. I consider the compost worth more per cord than the barn-yard manure."

Night Soil is a substance which possesses, when fresh, the most valuable fertilizing qualities, in a very concentrated form. It is also one which is liable to rapid and almost complete deterioration, as I have demonstrated by analyses. The only methods of getting the full effect of this material are, either to use it fresh, as is done by the Chinese and Japanese on a most extensive and offensive scale; or to compost it before it can decompose. The former method, will, it is to be hoped, never find acceptance among us. The latter plan has nearly all the advantages of the former, without its unpleasant features.

When the night soil falls into a vault, it may be composted, by simply sprinkling fine peat over its surface, once or twice weekly, as the case may require, i. e. as often as a bad odor prevails. The quantity thus added, may be from twice to ten times the bulk of the night soil,—the more within these limits, the better. When the vault is full, the mass should be removed, worked well over and after a few days standing, will be ready to use to manure corn, tobacco, etc., in the hill, or for any purpose to which guano or poudrette is applied. If it cannot be shortly used, it should be made into a compact heap, and covered with a thick stratum of peat. When signs of heating appear, it should be watched closely; and if the process attains too much violence, additional peat should be worked into it. Drenching with water is one of the readiest means of checking too much heating, but acts only temporarily. Dilution with peat to a proper point, which experience alone can teach, is the surest way of preventing loss. It should not be forgotten to put a thick layer of peat at the bottom of the vault to begin with.

Another excellent plan, when circumstances admit, is, to have the earth-floor where the night soil drops, level with the surface of the ground, or but slightly excavated, and a shed attached to the rear of the privy to shelter a good supply of peat as well as the compost itself. Operations are begun by putting down a layer of peat to receive the droppings; enough should be used to absorb all the urine. When this is nearly saturated, more should be sprinkled on, and the process is repeated until the accumulations must be removed to make room for more. Then, once a week or so, the whole is hauled out into the shed, well mixed, and formed into a compact heap, or placed as a layer upon a stratum of peat, some inches thick, and covered with the same. The quantity of first-class compost that may be made yearly upon any farm, if due care be taken, would astonish those who have not tried it. James Smith, of Deanston, Scotland, who originated our present system of Thorough Drainage, asserted, that the excrements of one man for a year, are sufficient to manure half an acre of land. In Belgium the manure from such a source has a commercial value of $9.00 gold.

It is certain, that the skillful farmer may make considerably more than that sum from it in New England, per annum. Mr. Hoyt, of New Canaan, Conn., says:—

"Our privies are deodorized by the use of muck, which is sprinkled over the surface of the pit once a week, and from them alone we thus prepare annually, enough "poudrette" to manure our corn in the hill."

Peruvian Guano, so serviceable in its first applications to light soils, may be composted with muck to the greatest advantage. Guano is an excellent material for bringing muck into good condition, and on the other hand the muck most effectually prevents any waste of the costly guano, and at the same time, by furnishing the soil with its own ingredients, to a greater or less degree prevents the exhaustion that often follows the use of guano alone. The quantity of muck should be pretty large compared to that of the guano,—a bushel of guano will compost six, eight, or ten of muck. Both should be quite fine, and should be well mixed, the mixture should be moist and kept covered with a layer of muck of several inches of thickness. This sort of compost would probably be sufficiently fermented in a week or two of warm weather, and should be made and kept under cover.

If no more than five or six parts of muck to one of guano are employed, the compost, according to the experience of Simon Brown, Esq., of the Boston Cultivator, (Patent Office Report for 1856), will prove injurious, if placed in the hill in contact with seed, but may be applied broadcast without danger.

The Menhaden or "White fish", so abundantly caught along our Sound coast during the summer months, or any variety of fish may be composted with muck, so as to make a powerful manure, with avoidance of the excessively disagreeable stench which is produced when these fish are put directly on the land. Messrs. Stephen Hoyt & Sons, of New Canaan, Conn., make this compost on a large scale. I cannot do better than to give entire Mr. Edwin Hoyt's account of their operations, communicated to me several years ago.

"During the present season, (1858,) we have composted about 200,000 white fish with about 700 loads (17,500 bushels) of muck. We vary the proportions somewhat according to the crop the compost is intended for. For rye we apply 20 to 25 loads per acre of a compost made with 4,500 fish, (one load) and with this manuring, no matter how poor the soil, the rye will be as large as a man can cradle. Much of ours we have to reap. For oats we use less fish, as this crop is apt to lodge. For corn, one part fish to ten or twelve muck is about right, while for grass or any top-dressing, the proportion of fish may be increased."

"We find it is best to mix the fish in the summer and not use the compost until the next spring and summer. Yet we are obliged to use in September for our winter rye a great deal of the compost made in July. We usually compost the first arrivals of fish in June for our winter grain; after this pile has stood three or four weeks, it is worked over thoroughly. In this space of time the fish become pretty well decomposed, though they still preserve their form and smell outrageously. As the pile is worked over, a sprinkling of muck or plaster is given to retain any escaping ammonia. At the time of use in September the fish have completely disappeared, bones and fins excepted."

"The effect on the muck is to blacken it and make it more loose and crumbly. As to the results of the use of this compost, we find them in the highest degree satisfactory. We have raised 30 to 35 bushels of rye per acre on land that without it could have yielded 6 or 8 bushels at the utmost. This year we have corn that will give 60 to 70 bushels per acre, that otherwise would yield but 20 to 25 bushels. It makes large potatoes, excellent turnips and carrots."

Fish compost thus prepared, is a uniform mass of fishy but not putrefactive odor, not disagreeable to handle. It retains perfectly all the fertilizing power of the fish. Lands, manured with this compost, will keep in heart and improve: while, as is well known to our coast farmers, the use of fish alone is ruinous in the end, on light soils.

It is obvious that any other easily decomposing animal matters, as slaughter-house offal, soap boiler's scraps, glue waste, horn shavings, shoddy, castor pummace, cotton seed-meal, etc., etc., may be composted in a similar manner, and that several or all these substances may be made together into one compost.

In case of the composts with yard manure, guano and other animal matters, the alkali, ammonia, formed in the fermentation, greatly promotes chemical change, and it would appear that this substance, on some accounts, excels all others in its efficacy. The other alkaline bodies, potash, soda and lime, are however scarcely less active in this respect, and being at the same time, of themselves, useful fertilizers, they also may be employed in preparing muck composts.

Potash-lye and soda-ash have been recommended for composting with muck; but, although they are no doubt highly efficacious, they are too costly for extended use.

The other alkaline materials that may be cheaply employed, and are recommended, are wood-ashes, leached and unleached, ashes of peat, shell marl, (consisting of carbonate of lime,) quick lime, gas lime, and what is called "salt and lime mixture."

With regard to the proportions to be used, no very definite rules can be laid down; but we may safely follow those who have had experience in the matter. Thus, to a cord of muck, which is about 100 bushels, may be added, of unleached wood ashes twelve bushels, or of leached wood ashes twenty bushels, or of peat ashes twenty bushels, or of marl, or of gas lime twenty bushels. Ten bushels of quick lime, slaked with water or salt-brine previous to use, is enough for a cord of muck.

Instead of using the above mentioned substances singly, any or all of them may be employed together.

The muck should be as fine and free from lumps as possible, and must be intimately mixed with the other ingredients by shoveling over. The mass is then thrown up into a compact heap, which may be four feet high. When the heap is formed, it is well to pour on as much water as the mass will absorb, (this may be omitted if the muck is already quite moist,) and finally the whole is covered over with a few inches of pure muck, so as to retain moisture and heat. If the heap is put up in the Spring, it may stand undisturbed for one or two months, when it is well to shovel it over and mix it thoroughly. It should then be built up again, covered with fresh muck, and allowed to stand as before until thoroughly decomposed. The time required for this purpose varies with the kind of muck, and the quality of the other material used. The weather and thoroughness of intermixture of the ingredients also materially affect the rapidity of decomposition. In all cases five or six months of summer weather is a sufficient time to fit these composts for application to the soil.

Mr. Stanwood of Colebrook, Conn., says: "I have found a compost made of two bushels of unleached ashes to twenty-five of muck, superior to stable manure as a top-dressing for grass, on a warm, dry soil."

N. Hart, Jr., of West Cornwall, Conn., states: "I have mixed 25 bushels of ashes with the same number of loads of muck, and applied it to 3/4 of an acre. The result was far beyond that obtained by applying 300 lbs. best guano to the same piece."

The use of "salt and lime mixture" is so strongly recommended, that a few words may be devoted to its consideration.

When quick-lime is slaked with a brine of common salt (chloride of sodium), there are formed by double decomposition, small portions of caustic soda and chloride of calcium, which dissolve in the liquid. If the solution stand awhile, carbonic acid is absorbed from the air, forming carbonate of soda: but carbonate of soda and chloride of calcium instantly exchange their ingredients, forming insoluble carbonate of lime and reproducing common salt.

When the fresh mixture of quick-lime and salt is incorporated with any porous body, as soil or peat, then, as Graham has shown, unequal diffusion of the caustic soda and chloride of calcium occurs from the point where they are formed, through the moist porous mass, and the result is, that the small portion of caustic soda which diffuses most rapidly, or the carbonate of soda formed by its speedy union with carbonic acid, is removed from contact with the chloride of calcium.

Soda and carbonate of soda are more soluble in water and more strongly alkaline than lime. They, therefore, act on peat more energetically than the latter. It is on account of the formation of soda and carbonate of soda from the lime and salt mixture, that this mixture exerts a more powerful decomposing action than lime alone. Where salt is cheap and wood ashes scarce, the mixture may be employed accordingly to advantage. Of its usefulness we have the testimony of practical men.

Says Mr. F. Holbrook of Vermont, (Patent Office Report for 1856, page 193.) "I had a heap of seventy-five half cords of muck mixed with lime in the proportion of a half cord of muck to a bushel of lime. The muck was drawn to the field when wanted in August. A bushel of salt to six bushels of lime was dissolved in water enough to slake the lime down to a fine dry powder, the lime being slaked no faster than wanted, and spread immediately while warm, over the layers of muck, which were about six inches thick; then a coating of lime and so on, until the heap reached the height of five feet, a convenient width, and length enough to embrace the whole quantity of the muck. In about three weeks a powerful decomposition was apparent, and the heap was nicely overhauled, nothing more being done to it till it was loaded the next Spring for spreading. The compost was spread on the plowed surface of a dry sandy loam at the rate of about fifteen cords to the acre, and harrowed in. The land was planted with corn and the crop was more than sixty bushels to the acre."

Other writers assert that they "have decomposed with this mixture, spent tan, saw dust, corn stalks, swamp muck, leaves from the woods, indeed every variety of inert substance, and in much shorter time than it could be done by any other means." (Working Farmer, Vol. III. p. 280.)

Some experiments that have a bearing on the efficacy of this compost will be detailed presently.

There is no doubt that the soluble and more active (caustic) forms of alkaline bodies exert a powerful decomposing and solvent action on peat. It is asserted too that the nearly insoluble and less active matters of this kind, also have an effect, though a less complete and rapid one. Thus, carbonate of lime in the various forms of chalk, shell marl,[6] old mortar, leached ashes and peat ashes, (for in all these it is the chief and most "alkaline" ingredient,) is recommended to compost with peat. Let us inquire whether carbonate of lime can really exert any noticeable influence in improving the fertilizing quality of peat.

In the case of vitriol peats, carbonate of lime is the cheapest and most appropriate means of destroying the noxious sulphate of protoxide of iron, and correcting their deleterious quality. When carbonate of lime is brought in contact with sulphate of protoxide of iron, the two bodies mutually decompose, with formation of sulphate of lime (gypsum) and carbonate of protoxide of iron. The latter substance absorbs oxygen from the air with the utmost avidity, and passes into the peroxide of iron, which is entirely inert.

The admixture of any earthy matter with peat, will facilitate its decomposition, and make it more active chemically, in so far as it promotes the separation of the particles of the peat from each other, and the consequent access of air. This benefit may well amount to something when we add to peat one-fifth of its bulk of marl or leached ashes, but the question comes up: Do these insoluble mild alkalies exert any direct action? Would not as much soil of any kind be equally efficacious, by promoting to an equal degree the contact of oxygen from the atmosphere?

There are two ways in which carbonate of lime may exert a chemical action on the organic matters of peat. Carbonate of lime, itself, in the forms we have mentioned, is commonly called insoluble in water. It is, however, soluble to a very slight extent; it dissolves, namely, in about 30,000 times its weight of pure water. It is nearly thirty times more soluble in water saturated with carbonic acid; and this solution has distinct alkaline characters. Since the water contained in a heap of peat must be considerably impregnated with carbonic acid, it follows that when carbonate of lime is present, the latter must form a solution, very dilute indeed, but still capable of some direct effect on the organic matters of the peat, when it acts through a long space of time. Again, it is possible that the solution of carbonate of lime in carbonic acid, may act to liberate some ammonia from the soluble portions of the peat, and this ammonia may react on the remainder of the peat to produce the same effects as it does in the case of a compost made with animal matters.

Whether the effects thus theoretically possible, amount to anything practically important, is a question of great interest. It often happens that opinions entertained by practical men, not only by farmers, but by mechanics and artisans as well, are founded on so untrustworthy a basis, are supported by trials so destitute of precision, that their accuracy may well be doubted, and from all the accounts I have met with, it does not seem to have been well established, practically, that composts made with carbonate of lime, are better than the peat and carbonate used separately.

Carbonate of lime (leached ashes, shell marl, etc.), is very well to use in conjunction with peat, to furnish a substance or substances needful to the growth of plants, and supply the deficiencies of peat as regards composition. Although in the agricultural papers, numerous accounts of the efficacy of such mixtures are given, we do not learn from them whether these bodies exert any such good effect upon the peat itself, as to warrant the trouble of making a compost.

4.—Experiments by the author on the effect of alkaline bodies in developing the fertilizing power of Peat.

During the summer of 1862, the author undertook a series of experiments with a view of ascertaining the effect of various composting materials upon peat.

Two bushels of peat were obtained from a heap that had been weathering for some time on the "Beaver Meadow," near New Haven. This was thoroughly air-dried, then crushed by the hand, and finally rubbed through a moderately fine sieve. In this way, the peat was brought to a perfectly homogeneous condition.

Twelve-quart flower-pots, new from the warehouse, were filled as described below; the trials being made in duplicate:—

Pots 1 and 2 contained each 270 grammes of peat.

Pots 3 and 4 contained each 270 grammes of peat, mixed-with 10 grammes of ashes of young grass.

Pots 5 and 6 contained each 270 grammes of peat, 10 grammes of ashes, and 10 grammes of carbonate of lime.

Pots 7 and 8 contained each 270 grammes of peat, 10 grammes of ashes, and 10 grammes of slaked (hydrate of) lime.

Pots 9 and 10 contained each 270 grammes of peat, 10 grammes of ashes, and 5 grammes of lime, slaked with strong solution of common salt.

Pots 11 and 12 contained each 270 grammes of peat, 10 grammes of ashes, and 3 grammes of Peruvian guano.

In each case the materials were thoroughly mixed together, and so much water was cautiously added as served to wet them thoroughly. Five kernels of dwarf (pop) corn were planted in each pot, the weight of each planting being carefully ascertained.

The pots were disposed in a glazed case within a cold grapery,[7] and were watered when needful with pure water. The seeds sprouted duly, and developed into healthy plants. The plants served thus as tests of the chemical effect of carbonate of lime, of slaked lime, and of salt and lime mixture, on the peat. The guano pots enabled making a comparison with a well-known fertilizer. The plants were allowed to grow until those best developed, enlarged above, not at the expense of the peat, etc., but of their own lower leaves, as shown by the withering of the latter. They were then cut, and, after drying in the air, were weighed with the subjoined results.

VEGETATION EXPERIMENTS IN PEAT COMPOSTS. KEY A - Weight of crops in grammes. B - Comparative weight of crops, the sum of 1. and 2. taken as unity. C - Ratio of weight of crops to weight of seeds, the latter assumed as unity.

-+ -+ + - Nos. Medium of Growth. A B C -+ -+ + - 1 } 1.61} 2 } Peat alone. 2.59} 4.20 1 2-1/2 3 } 14.19} 4 } Peat, and ashes of grass, 18.25} 32.44 8 20-1/2 5 } 18.19} 6 } Peat, ashes, and carbonate of lime, 20.25} 38.44 9 25-1/2 7 } 21.49} 8 } Peat, ashes, and slaked lime, 20.73} 42.22 10 28-1/2 9 } 23.08} 10 } Peat, ashes, slaked lime, and salt, 23.34} 46.42 11 30-1/2 11 } 26.79} 12 } Peat, ashes, and Peruvian Guano, 26.99} 53.78 13 35-1/2 -+ -+ + -

Let us now examine the above results. The experiments 1 and 2, demonstrate that the peat itself is deficient in something needful to the plant. In both pots, but 4.2 grammes of crop were produced, a quantity two and a half times greater than that of the seeds, which weighed 1.59 grammes. The plants were pale in color, slender, and reached a height of but about six inches.

Nos. 3 and 4 make evident what are some of the deficiencies of the peat. A supply of mineral matters, such as are contained in all plants, being made by the addition of ashes, consisting chiefly of phosphates, carbonates and sulphates of lime, magnesia and potash, a crop is realized nearly eight times greater than in the previous cases; the yield being 32.44 grammes, or 20-1/2 times the weight of the seed. The quantity of ashes added, viz.:—10 grammes, was capable of supplying every mineral element, greatly in excess of the wants of any crop that could be grown in a quart of soil. The plants in pots 3 and 4 were much stouter than those in 1 and 2, and had a healthy color.

The experiments 5 and 6 appear to demonstrate that carbonate of lime considerably aided in converting the peat itself into plant-food. The ashes alone contained enough carbonate of lime to supply the wants of the plant in respect to that substance. More carbonate of lime could only operate by acting on the organic matters of the peat. The amount of the crop is raised by the effect of carbonate of lime from 32.44 to 38.44 grammes, or from 20-1/2 to 25-1/2 times that of the seed.

Experiments 7 and 8 show, that slaked lime has more effect than the carbonate, as we should anticipate. Its influence does not, however, exceed that of the carbonate very greatly, the yield rising from 38.44 to 42.22 grammes, or from 25-1/2 to 28-1/2 times the weight of the seed. In fact, quick-lime can only act as such for a very short space of time, since it rapidly combines with the carbonic acid, which is supplied abundantly by the peat. In experiments 7 and 8, a good share of the influence exerted must therefore be actually ascribed to the carbonate, rather than to the quick-lime itself.

In experiments 9 and 10, we have proof that the "lime and salt mixture" has a greater efficacy than lime alone, the crop being increased thereby from 42.22, to 46.42 grammes, or from 28-1/2 to 30-1/2 times that of the seed.

Finally, we see from experiments 11 and 12 that in all the foregoing cases it was a limited supply of nitrogen that limited the crop; for, on adding Peruvian guano, which could only act by this element (its other ingredients, phosphates of lime and potash, being abundantly supplied in the ashes), the yield was carried up to 53.78 grammes, or 35-1/2 times the weight of the seed, and 13 times the weight of the crop obtained from the unmixed peat.

5.—The Examination of Peat (muck and marsh-mud) with reference to its Agricultural Value.

Since, as we are forced to conclude, the variations in the composition of peat stand in no recognizable relations to differences of appearance, it is only possible to ascertain the value of any given specimen by actual trial or by chemical investigation.

The method by practical trial is usually the cheaper and more satisfactory of the two, though a half year or more is needful to gain the desired information.

It is sufficient to apply to small measured plots of ground, each say two rods square, known quantities of the fresh, the weathered, and the composted peat in order, by comparison of the growth and weight of the crop, to decide the question of their value.

Peat and its composts are usually applied at rates ranging from 20 to 40 wagon or cart loads per acre. There being 160 square rods in the acre, the quantity proper to a plot of two rods square (= four square rods,) would be one half to one load.

The composts with stable manure and lime, or salt and lime mixture, are those which, in general, it would be best to experiment with. From the effects of the stable manure compost, could be inferred with safety the value of any compost, of which animal manure is an essential ingredient.

One great advantage of the practical trial on the small scale is, that the adaptation of the peat or of the compost to the peculiarities of the soil, is decided beyond a question.

It must be borne in mind, however, that the results of experiments can only be relied upon, when the plots are accurately measured, when the peat, etc., are applied in known quantities, and when the crops are separately harvested and carefully weighed.

If experiments are made upon grass or clover, the gravest errors may arise by drawing conclusions from the appearance of the standing crop. Experience has shown that two clover crops, gathered from contiguous plots differently manured, may strikingly differ in appearance, but yield the same amounts of hay.

The chemical examination of a peat may serve to inform us, without loss of time, upon a number of important points.

To test a peat for soluble iron salts which might render it deleterious, we soak and agitate a handful for some hours, with four or five times its bulk of warm soft water. From a good fresh-water peat we obtain, by this treatment, a yellow liquid, more or less deep in tint, the taste of which is very slight and scarcely definable.

From a vitriol peat we get a dark-brown or black solution, which has a bitter, astringent, metallic or inky taste, like that of copperas.

Salt peat will yield a solution having the taste of salt-brine, unless it contains iron, when the taste of the latter will prevail.

On evaporating the water-solution to dryness and heating strongly in a China cup, a vitriol peat gives off white choking fumes of sulphuric acid, and there remains, after burning, brown-red oxide of iron in the dish.

The above testings are easily conducted by any one, with the ordinary conveniences of the kitchen.

Those that follow, require, for the most part, the chemical laboratory, and the skill of the practised chemist, for satisfactory execution.

Besides testing for soluble iron compounds, as already indicated, the points to be regarded in the chemical examination, are:—

1st. Water or moisture.—This must be estimated, because it is so variable, and a knowledge of its quantity is needful, if we will compare together different samples. A weighed amount of the peat is dried for this purpose at 212 deg. F., as long as it suffers loss.

2d. The proportions of organic matter and ash are ascertained by carefully burning a weighed sample of the peat. By this trial we distinguish between peat with 2 to 10 per cent. of ash and peaty soil, or mud, containing but a few per cent. of organic matter.

This experiment may be made in a rough way, but with sufficient accuracy for common purposes, by burning a few lbs. or ozs. of peat upon a piece of sheet iron, or in a sauce pan, and noting the loss, which includes both water and organic matter.

3d. As further regards the organic matters, we ascertain the extent to which the peaty decomposition has taken place by boiling with dilute solution of carbonate of soda. This solvent separates the humic and ulmic acids from the undecomposed vegetable fibers.

For practical purposes this treatment with carbonate of soda may be dispensed with, since the amount of undecomposed fiber is gathered with sufficient accuracy from careful inspection of the peat.

Special examination of the organic acids is of no consequence in the present state of our knowledge.

4th. The proportion of nitrogen is of the first importance to be ascertained. In examinations of 30 samples of peat, I have found the content of nitrogen to range from 0.4 to 2.9 per cent., the richest containing seven times as much as the poorest. It is practically a matter of great moment whether, for example, a Peruvian guano contains 16 per cent. of nitrogen as it should, or but one-seventh that amount, as it may when grossly adulterated. In the same sense, it is important before making a heavy outlay in excavating and composting peat, to know whether (as regards nitrogen) it belongs to the poorer or richer sorts. This can only be done by the complicated methods known to the chemist.

5th. The estimation of ammonia (actual or ready-formed,) is a matter of scientific interest, but subordinate in a practical point of view.

6th. Nitric acid and nitrates can scarcely exist in peat except where it is well exposed to the air, in a merely moist but not wet state. Their estimation in composts is of great interest, though troublesome to execute.

7th. As regards the ash, its red color indicates iron. Pouring hydrochloric acid upon it, causes effervescence in the presence of carbonate of lime. This compound, in most cases, has been formed in the burning, from humate and other organic salts of lime. Sand, or clay, being insoluble in the acid, remains, and may be readily estimated.

Phosphoric acid and alkalies, especially potash, are, next to lime, the important ingredients of the ash. Magnesia and sulphuric acid, rank next in value. Their estimation requires a number of tedious operations, and can scarcely be required for practical purposes, until more ready methods of analyses shall have been discovered.

8th. The quantity of matters soluble in water has considerable interest, but is not ordinarily requisite to be ascertained.

6.—Composition of Connecticut Peats.

In the years 1857 and 1858, the author was charged by the Connecticut State Agricultural Society[8] with the chemical investigation of 33 samples of peat and swamp muck, sent to him in compliance with official request.

In the foregoing pages, the facts revealed by the laborious analyses executed on these samples, have been for the most part communicated, together with many valuable practical results derived from the experience of the gentlemen who sent in the specimens. The analytical data themselves appear to me to be worthy of printing again, for the information of those who may hereafter make investigations in the same direction.—See Tables I, II, and III, p.p. 89, 90, and 91.

The specimens came in all stages of dryness. Some were freshly dug and wet, others had suffered long exposure, so that they were air-dry; some that were sent in the moist state, became dry before being subjected to examination; others were prepared for analysis while still moist.

A sufficient quantity of each specimen was carefully pulverized, intermixed, and put into a stoppered bottle and thus preserved for experiment.

The analyses were begun in the winter of 1857 by my assistant, Edward H. Twining, Esq. The samples 1 to 17 of the subjoined tables were then analyzed. In the following year the work was continued on the remaining specimens 18—33 by Dr. Robert A. Fisher. The method of analysis was the same in both cases, except in two particulars.

In the earlier analyses, 1 to 17 inclusive, the treatment with carbonate of soda was not carried far enough to dissolve the whole of the soluble organic acids. It was merely attempted to make comparative determinations by treating all alike for the same time, and with the same quantity of alkali. I have little doubt that in some cases not more than one-half of the portion really soluble in carbonate of soda is given as such. In the later analyses, 18 to 33, however, the treatment was continued until complete separation of the soluble organic acids was effected.

By acting on a peat for a long time with a hot solution of carbonate of soda, there is taken up not merely a quantity of organic matter, but inorganic matters likewise enter solution. Silica, oxyd of iron and alumina are thus dissolved. In this process too, sulphate of lime is converted into carbonate of lime.

The total amount of these soluble inorganic matters has been determined with approximate accuracy in analyses 18 to 33.

In the analyses 1 to 17 the collective amount of matters soluble in water was determined. In the later analyses the proportions of organic and inorganic matters in the water-solution were separately estimated.

The process of analysis as elaborated and employed by Dr. Fisher and the author, is as follows:

I. To prepare a sample for analysis, half a pound, more or less, of the substance is pulverized and passed through a wire sieve of 24 meshes to the inch. It is then thoroughly mixed and bottled.

II. 2 grammes of the above are dried (in tared watch-glasses) at the temperature of 212 degrees, until they no longer decrease in weight. The loss sustained represents the amount of water, (according to MARSILLY, Annales des Mines, 1857, XII., 404, peat loses carbon if dried at a temperature higher than 212 degrees.)

III. The capsule containing the residue from I. is slowly heated to incipient redness, and maintained at that temperature until the organic matter is entirely consumed. The loss gives the total amount of organic, the residue the total amount of inorganic matter.

NOTE.—In peats containing sulphate of the protoxide of iron, the loss that occurs during ignition is partly due to the escape of sulphuric acid, which is set free by the decomposition of the above mentioned salt of iron. But the quantity is usually so small in comparison with the organic matter, that it may be disregarded. The same may be said of the combined water in the clay that is mixed with some mucks, which is only expelled at a high temperature.

IV. 3 grammes of the sample are digested for half an hour, with 200 cubic centimeters (66.6 times their weight,) of boiling water, then removed from the sand bath, and at the end of twenty-four hours, the clear liquid is decanted. This operation is twice repeated upon the residue; the three solutions are mixed, filtered, concentrated, and finally evaporated to dryness (in a tared platinum capsule,) over a water bath. The residue, which must be dried at 212 degrees, until it ceases to lose weight, gives the total amount soluble in water. The dried residue is then heated to low redness, and maintained at that temperature until the organic matter is burned off. The loss represents the amount of organic matter soluble in water, the ash gives the quantity of soluble inorganic matter.

V. 1 gramme is digested for two hours, at a temperature just below the boiling point, with 100 cubic centimeters of a solution containing 5 per cent. of crystallized carbonate of soda. It is then removed from the sand bath and allowed to settle. When the supernatant liquid has become perfectly transparent, it is carefully decanted. This operation is repeated until all the organic matter soluble in this menstruum is removed; which is accomplished as soon as the carbonate of soda solution comes off colorless. The residue, which is to be washed with boiling water until the washings no longer affect test papers, is thrown upon a tared filter, and dried at 212 degrees. It is the total amount of organic and inorganic matter insoluble in carbonate of soda. The loss that it suffers upon ignition, indicates the amount of organic matter, the ash gives the inorganic matter.

NOTE.—The time required to insure perfect settling after digesting with carbonate of soda solution, varies, with different peats, from 24 hours to several days. With proper care, the results obtained are very satisfactory. Two analyses of No. 6, executed at different times, gave total insoluble in carbonate of soda—1st analysis 23.20 per cent.; 2d analysis 23.45 per cent. These residues yielded respectively 14.30 and 14.15 per cent. of ash.

VI. The quantity of organic matter insoluble in water but soluble in solution of carbonate of soda, is ascertained by deducting the joint weight of the amounts soluble in water, and insoluble in carbonate of soda, from the total amount of organic matter present. The inorganic matter insoluble in water, but soluble in carbonate of soda, is determined by deducting the joint weight of the amounts of inorganic matter soluble in water, and insoluble in carbonate of soda, from the total inorganic matter.

VII. The amount of nitrogen is estimated by the combustion of 1 gramme with soda-lime in an iron tube, collection of the ammonia in a standard solution of sulphuric acid, and determination of the residual free acid by an equivalent solution of caustic potash and a few drops of tincture of cochineal as an indicator.

The results of the analyses are given in the following Tables. Table I. gives the direct results of analysis. In Table II. the analyses are calculated on dry matter, and the nitrogen upon the organic matters. Table III. gives a condensed statement of the external characters and agricultural value[9] of the samples in their different localities, and the names of the parties supplying them.

TABLE I.-COMPOSITION OF CONNECTICUT PEATS AND MUCKS.

KEY: A - Soluble in water. B - Insol. in water, but soluble in carbonate of soda. C - Insol. in water and carbonate of soda. D - Total. E - Water. F - Nitrogen. G - Total matters soluble in water.

- - ORGANIC MATTER. From Whom and - - - - Whence Received A B C D -~~~~v~~~~ - - 1. Lewis M. Norton. Goshen Conn. 17.63 34.79 52.42 2. " " " 60.02 11.65 71.67 3. " " " 50.60 29.75 80.35 4. Messrs. Pond & Miles. " Milford Conn. 65.15 11.95 77.10 5. " " " 67.75 16.65 84.40 6. Samuel Camp. Plainville Conn. 43.20 8.90 52.10 7. Russell U. Peck. Berlin Conn. 38.49 30.51 69.00 8. Rev. B. F. Northrop. Griswold Conn. 42.30 10.15 52.45 9. J. H. Stanwood. Colebrook Conn. 49.65 7.40 57.05 10. N. Hart, Jr. West Cornwall Conn. 55.11 10.29 65.40 11. A. L. Loveland. North Granby " 38.27 2.89 41.16 12. Daniel Buck, Jr. Poquonock " 27.19 48.84 76.03 13. " " " 33.66 40.51 74.17 14. Philip Scarborough Brooklyn Conn. 51.45 25.00 76.45 15. Adams White. Brooklyn " 54.38 23.14 77.52 16. Paris Dyer. Brooklyn " 18.86 5.02 23.88 17. Perrin Scarborough. Brooklyn Conn. 43.27 16.83 60.10 18. Geo. K. Virgin. Collinsville Conn. 2.21 20.57 8.25 31.03 19. " " " 1.12 9.19 5.10 15.41 20. " " " 0.72 9.31 3.65 13.68 21. S. Mead. New Haven Conn. 3.30 40.52 8.20 52.02 22. Edwin Hoyt. New Canaan " 2.84 13.42 7.55 23.81 23. " " " 2.34 13.49 8.05 23.88 24. " " " 1.15 17.29 8.00 26.44 25. A. M. Haling. Rockville " 3.43 52.15 8.65 64.23 26. " " " 3.87 71.57 8.44 83.88 27. " " " 3.87 44.04 4.25 52.16 28. Albert Day. Brooklyn " 2.45 46.25 6.35 55.05 29. C. Goodyear. New Haven " 1.80 45.42 10.35 57.57 30. Rev. Wm. Clift Stonington " 3.33 51.68 9.80 64.81 31. Henry Keeler. South Salem N. Y. 2.13 45.12 12.05 59.30 32. John Adams. Salisbury Conn. 1.71 42.87 10.65 55.23 33. Rev. Wm. Clift. Stonington " 5.40 16.72 7.25 29.37 - Average 2.06

- - - - - INORGANIC MATTER. From Whom and - - - - Whence Received A B C D E F G - - - - - - - - 1. Lewis M. Norton. Goshen Conn. 35.21 12.37 1.28 1.54 2. " " " 8.00 20.33 1.85 3. " " " 4.52 15.13 1.90 2.51 4. Messrs. Pond & Miles. " Milford Conn. 3.23 19.67 1.20 1.63 5. " " " 2.00 13.60 .95 3.42 6. Samuel Camp. ~~~~v~~~~ Plainville Conn. 14.90 14.80 29.20 18.70 2.10 2.50 7. Russell U. Peck. Berlin Conn. 13.59 17.41 1.62 2.61 8. Rev. B. F. Northrop. Griswold Conn. 34.70 12.85 1.31 1.64 9. J. H. Stanwood. Colebrook Conn. 4.57 38.38 1.23 1.83 10. N. Hart, Jr. West Cornwall Conn. 14.89 19.71 2.10 6.20 11. A. L. Loveland. North Granby " 47.24 11.60 1.00 .75 12. Daniel Buck, Jr. Poquonock " 5.92 18.05 2.40 2.94 13. " " " 8.63 17.20 2.40 1.80 14. Philip Scarborough. Brooklyn Conn. 7.67 15.88 1.20 1.43 15. Adams White. Brooklyn " 9.03 13.45 2.89 5.90 16. Paris Dyer. Brooklyn " 67.77 8.35 1.03 2.63 17. Perrin Scarborough. Brooklyn Conn. 25.78 14.12 0.86 15.13 18. Geo. K. Virgin. Collinsville Conn. 0.32 9.41 48.05 57.78 11.19 0.64 2.53 19. " " " 0.28 1.08 48.65 50.01 34.58 0.34 1.40 20. " " " 0.25 0.76 28.20 29.21 57.11 0.28 .97 21. S. Mead. New Haven Conn. 2.60 10.02 23.90 36.52 11.46 1.51 5.90 22. Edwin Hoyt. New Canaan " 2.72 19.88 46.30 68.90 7.29 0.45 5.56 23. " " " 1.54 12.42 56.20 70.16 5.96 0.90 3.88 24. " " " 1.67 14.13 51.10 66.90 6.66 1.01 2.82 25. A. M. Haling. Rockville " 0.35 0.16 4.90 5.41 30.36 1.62 3.78 26. " " " 0.23 1.98 2.21 13.91 1.32 4.10 27. " " " 0.51 4.07 5.05 9.63 38.21 1.88 4.38 28. Albert Day. Brooklyn " 0.32 0.65 5.40 6.37 38.58 0.84 2.77 29. C. Goodyear. New Haven " 0.35 7.98 18.80 27.13 15.30 1.68 2.15 30. Rev. Wm. Clift Stonington " 2.82 5.86 8.68 26.51 0.95 6.15 31. Henry Keeler. South Salem N. Y. 0.78 3.79 16.70 21.27 19.43 1.57 2.91 32. John Adams. Salisbury Conn. 1.02 1.33 14.35 16.70 28.07 1.76 2.73 33. Rev. Wm. Clift. Stonington " 7.40 6.40 48.05 61.85 8.78 1.32 2.80 - - - Average 1.44 1.37 3.72



TABLE II.-COMPOSITION OF CONNECTICUT PEATS AND MUCKS. Calculated in the dry state: the percentage of nitrogen calculated also on organic matters.

KEY: A - In this table the matters soluble in water and the nitrogen are calculated to two places of decimals; the other ingredients are expressed in round numbers. B - Soluble in water. C - Insol. in water, but soluble in carbonate of soda. D - Insol. in water and carbonate of soda. E - Total. F - Total matters soluble in water. G - Nitrogen. H - Nitrogen in per cent. of the organic matter.

-+ -+ ORGANIC MATTER. -+ -+ -+ -+ A B C D E -+~~~~v~~~~+ -+ -+ 1. Lewis M. Norton. Goshen Conn. 20 40 60 2. " " " 75 15 90 3. " " " 60 35 95 5. Messrs. Pond & Miles. " Milford Conn. 81 15 96 5. " " " 79 19 98 6. Samuel Camp. Plainville Conn. 53 11 64 7. Russell U. Peck. Berlin Conn. 46 37 83 8. Rev. B. F. Northrop. Griswold Conn. 48 11 59 9. J. H. Stanwood. Colebrook Conn. 75 11 86 10. N. Hart, Jr. West Cornwall Conn. 69 13 82 11. A. L. Loveland. North Granby " 43 4 47 12. Daniel Buck, Jr. Poquonock " 33 60 93 13. " " " 41 49 90 14. Philip Scarborough. Brooklyn Conn. 61 30 91 15. Adams White. Brooklyn " 63 27 90 16. Paris Dyer. Brooklyn " 21 5 26 17. Perrin Scarborough. Brooklyn Conn. 62 8 70 18. Geo. K. Virgin. Collinsville Conn. 2.48 23 9 35 19. " " " 1.72 14 8 23 20. " " " 1.67 22 8 32 21. Solomon Mead. New Haven Conn. 3.70 48 9 60 22. Edwin Hoyt. New Canaan " 3.05 14 8 26 23. " " " 2.47 14 8 25 24. " " " 1.23 18 9 28 25. A. M. Haling. Rockville " 4.90 75 12 92 26. " " " 4.50 83 10 97 27. " " " 6.24 71 7 84 28. Albert Day. Brooklyn " 4.01 76 10 90 29. C. Goodyear. New Haven " 2.11 54 12 68 30. Rev. Wm. Clift Stonington " 4.56 71 13 88 31. Henry Keeler. South Salem N. Y. 2.66 56 15 73 32. John Adams. Salisbury Conn. 2.37 59 15 76 33. Rev. Wm. Clift. Stonington " 5.93 18 8 32 -+ -+ -+ -+ -+

-+ -+ -+ -+ - INORGANIC MATTER. -+ -+ -+ - A B C D E F G H -+ -+ -+ -+ -+ -+ -+ - 1. Lewis M. Norton. Goshen Conn. 40 1.75 1.46 2.25 2. " " " 10 2.32 2.58 3. " " " 5 2.95 2.23 2.36 5. Messrs. Pond & Miles. " Milford Conn. 4 2.03 1.49 1.55 5. " " " ~~~~v~~~~ 2 3.97 1.09 1.12 6. Samuel Camp. 18 18 Plainville Conn. 36 3.08 2.58 4.03 7. Russell U. Peck. Berlin Conn. 17 3.27 1.96 2.34 8. Rev. B. F. Northrop. Griswold Conn. 41 1.88 1.50 2.49 9. J. H. Stanwood. Colebrook Conn. 14 2.77 1.99 2.15 10. N. Hart, Jr. West Cornwall Conn. 18 7.75 2.61 3.21 11. A. L. Loveland. North Granby " 53 .85 1.13 2.43 12. Daniel Buck, Jr. Poquonock " 7 3.58 2.92 3.15 13. " " " 10 2.16 2.89 2.23 14. Philip Scarborough. Brooklyn Conn. 9 1.70 1.42 1.57 15. Adams White. Brooklyn " 10 6.78 3.33 3.72 16. Paris Dyer. Brooklyn " 74 2.85 1.12 4.31 17. Perrin Scarborough. Brooklyn Conn. 30 17.59 1.00 1.43 18. Geo. K. Virgin. Collinsville Conn. 0.35 11 54 65 2.83 0.72 2.06 19. " " " .43 2 75 77 2.15 0.51 2.20 20. " " " .58 2 66 68 2.25 0.65 2.04 21. Solomon Mead. New Haven Conn. 2.92 11 27 40 6.62 1.70 2.90 22. Edwin Hoyt. New Canaan " 2.92 21 50 74 6.07 0.48 1.88 23. " " " 1.63 13 60 75 4.10 0.95 3.76 24. " " " 1.79 15 55 72 3.02 1.08 3.82 25. A. M. Haling. Rockville " .50 7 8 5.40 2.32 2.52 26. " " " .27 2 3 4.77 1.53 1.57 27. " " " .82 7 8 16 7.06 3.04 3.64 28. Albert Day. Brooklyn " .52 1 8 10 4.58 1.36 1.52 29. C. Goodyear. New Haven " .40 9 22 32 2.51 1.98 2.91 30. Rev. Wm. Clift Stonington " 3.86 8 12 8.42 1.29 1.46 31. Henry Keeler. South Salem N. Y. .97 5 21 27 3.63 1.98 2.64 32. John Adams. Salisbury Conn. 1.40 2 20 24 3.77 2.44 3.18 33. Rev. Wm. Clift. Stonington " 8.13 7 53 68 14.06 1.44 4.49 -+ -+ -+ -+ -+ -+ -+ -

TABLE III.—DESCRIPTION, ETC., OF PEATS AND MUCKS.

No. Color.

1. Lewis M. Norton chocolate-brown, . 2. " " " " 3. " " light-brown, 4. Messrs. Pond & Miles chocolate-brown, 5. " " brownish-red, 6. Samuel Camp black, 7. Russell U. Peck chocolate-brown, 8. Rev. B. F. Northrop grayish-brown, 9. J. H. Stanwood chocolate-brown, 10. N. Hart, Jr brownish-black, 11. A. L. Loveland black, 12. Daniel Buck, Jr chocolate-brown, 13. " " " " 14. Philip Scarborough 15. Adams White chocolate-brown, 16. Paris Dyer grayish-black, 17. Perrin Scarborough chocolate-brown, 18. Geo. K. Virgin light brownish-gray 19. " " chocolate-brown, 20. " " black, 21. Solomon Mead grayish-brown, 22. Edwin Hoyt brownish-gray, 23. " " " 24. " " " 25. A. M. Haling chocolate-brown, 26. " " " " 27. " " " " 28. Albert Day dark-brown, 29. C. Goodyear black, 30. Rev. Wm. Clift chocolate-brown, 31. Henry Keeler light-brown, 32. John Adams " 33. Rev. Wm. Clift dark ash-gray,

Condition at Time of Analysis, No. Reputed value, etc.

1. Lewis M. Norton air-dry, tough, compact, heavy; from bottom; 3 to 4 feet deep; very good in compost. 2. " " " tough, compact, heavier than 1, from near surface; very good in compost. 3. " " " coherent but light, from between 1 and 2, very good in compost. 4. Messrs. Pond & Miles " coherent but light, surface peat, considered better than No. 5; good in compost. 5. " " " very light and loose in texture, from depth of 3 feet, good in compost. 6. Samuel Camp " hard lumps, half as good as yard manure, in compost equal to yard manure. 7. Russell U. Peck " is good fresh, long exposed, half as good as barn-yard manure. 8. Rev. B. F. Northrop " light, easily crushed masses containing sand, has not been used alone, good in compost. 9. J. H. Stanwood moist, hard lumps, used fresh good after first year; excellent in compost. 10. N. Hart, Jr air-dry, hard lumps, excellent in compost. 11. A. L. Loveland " hard lumps, contains grains of coarse sand. 12. Daniel Buck, Jr " coherent cakes, good as top dressing on grass when fresh; excellent in compost. 13. " " " light surface layers of No. 12. 14. Philip Scarborough " after exposure over winter, has one-third value of yard-manure. 15. Adams White " hard lumps, good in compost, causes great growth of straw. 16. Paris Dyer " easily crushed lumps, largely admixed with soil. 17. Perrin Scarborough " well-characterized "vitriol peat;" in compost, after 1 year's exposure, gives indifferent results. 18. Geo. K. Virgin " light, coherent surface peat; sample long exposed; astonishing results on sandy soil. 19. " " moist, crumbly, contains much sand, four feet from surface. 20. " " wet. 21. Solomon Mead air-dry, light, porous, coherent from grass roots; long weathered, good; fresh, better in compost. 22. Edwin Hoyt " loose, light, much mixed with soil, good in compost. 23. " " " No. 22 saturated with horse urine, darker than No. 22. 24. " " " No. 22 composted with white fish, darker than No. 23; fish-bones evident. 25. A. M. Haling moist, fresh dug. 26. " " air-dry, No. 25 after two year's weathering. 27. " " moist, fresh dug, good substitute for yard manure as top-dressing on grass. 28. Albert Day " coherent and hard; fresh dug, but from surface where weathered; injurious to crops; vitriol peat. (?) 29. C. Goodyear air-dry, very hard tough cakes; when fresh dug, "as good as cow dung." 30. Rev. Wm. Clift moist, from an originally fresh water bog, broken into 100 years ago by tide, now salt marsh; good after weathering. 31. Henry Keeler air-dry, leaf-muck, friable; when fresh, appears equal to good yard manure. 32. John Adams moist, overlies shell marl, fresh or weathered does not compare with ordinary manure. 33. Rev. Wm. Clift air-dry, from bottom of salt ditch, where tide flows daily; contains sulphate of iron.

FOOTNOTES:

[2] The oxygen thus absorbed by water, serves for the respiration of fish and aquatic animals.

[3] This sample contained also fish-bones, hence the larger content of nitrogen was not entirely due to absorbed ammonia.

[4] Reichardt's analyses are probably inaccurate, and give too much ammonia and nitric acid.

[5] These analyses were executed—A by Professor G. F. Barker; B by Mr. O. C. Sparrow; C by Mr. Peter Collier.

[6] Shell marl, consisting of fragments and powder of fresh-water shells, is frequently met with, underlying peat beds. Such a deposit occurs on the farm of Mr. John Adams, in Salisbury, Conn. It is eight to ten feet thick. An air-dry sample, analyzed under the writer's direction, gave results as follows:

"Water 30.62 {soluble in water 0.70} Organic matter { } 6.52 {insoluble in water 5.82} Carbonate of lime 57.09 Sand 1.86 Oxide of iron and alumina, with traces of potash, magnesia, sulphuric and phosphoric acid 3.91 ———- 100.00

Another specimen from near Milwaukee, Wis., said to occur there in immense quantities underlying peat, contained, by the author's analysis—

Water 1.14 Carbonate of lime 92.41 Carbonate of magnesia 3.43 Peroxide of iron with a trace of phosphoric acid 0.92 Sand 1.60 ——— 99.50



[7] To the kindness of Joseph Sheffield, Esq., of New Haven, the author is indebted for facilities in carrying on these experiments.

[8] At the instigation of Henry A. Dyer, Esq., at that time the Society's Corresponding Secretary.

[9] Derived from the communications published in the author's Report. Trans. Conn. State Ag. Soc. 1858 p.p. 101-153.



PART III.

ON PEAT AS FUEL.

1.—Kinds of peat that make the best fuel.

The value of peat for fuel varies greatly, like its other qualities. Only those kinds which can be cut out in the shape of coherent blocks, or which admit of being artificially formed into firm masses, are of use in ordinary stoves and furnaces. The powdery or friable surface peat, which has been disintegrated by frost and exposure, is ordinarily useless as fuel, unless it be rendered coherent by some mode of preparation. Unripe peat which contains much undecomposed moss or grass roots, which is therefore very light and porous, is in general too bulky to make an effective heating material before subjection to mechanical treatment.

The best peat for burning, is that which is most free from visible fiber or undecomposed vegetable matters, which has therefore a homogeneous brown or black aspect, and which is likewise free from admixture of earthy substances in the form of sand or clay. Such peat is unctuous when moist, shrinks greatly on drying, and forms hard and heavy masses when dry. It is usually found at a considerable depth, where it has been subjected to pressure, and then has such consistence as to admit of cutting out in blocks; or it may exist as a black mud or paste at the bottom of bogs and sluices.

The value of peat as fuel stands in direct ratio to its content of carbon. We have seen that this ranges from 51 to 63 per cent. of the organic matter, and the increase of carbon is related to its ripeness and density. The poorest, youngest peat, has the same proportion of carbon as exists in wood. It does not, however, follow that its heating power is the same. The various kinds of wood have essentially the same proportion of carbon, but their heating power is very different. The close textured woods—those which weigh the most per cord—make the best fuel for most purposes. We know, that a cord of hickory will produce twice as much heat as a cord of bass-wood. Peat, though having the same or a greater proportion of carbon, is generally inferior to wood on account of its occupying a greater bulk for a given weight, a necessary result of its porosity. The best qualities of peat, or poor kinds artificially condensed, may, on the other hand, equal or exceed wood in heating power, bulk for bulk. One reason that peat is, in general, inferior to wood in heating effect, lies in its greater content of incombustible ash. Wood has but 0.5 to 1.5 per cent. of mineral matters, while peat contains usually 5 to 10 per cent., and often more. The oldest, ripest peats are those which contain the most carbon, and have at the same time the greatest compactness. From these two circumstances they make the best fuel.

It thus appears that peat which is light, loose in structure, and much mixed with clay or sand, is a poor or very poor article for producing heat: while a dense pure peat is very good.

A great drawback to the usefulness of most kinds of peat-fuel, lies in their great friability. This property renders them unable to endure transportation. The blocks of peat which are commonly used in most parts of Germany as fuel, break and crumble in handling, so that they cannot be carried far without great waste. Besides, when put into a stove, there can only go on a slow smouldering combustion as would happen in cut tobacco or saw-dust. A free-burning fuel must exist in compact lumps or blocks, which so retain their form and solidity, as to admit of a rapid draught of air through the burning mass.

The bulkiness of ordinary peat fuel, as compared with hard wood, and especially with coal, likewise renders transportation costly, especially by water, where freights are charged by bulk and not by weight, and renders storage an item of great expense.

The chief value of that peat fuel, which is simply cut from the bog, and dried without artificial condensation, must be for the domestic use of the farmer or villager who owns a supply of it not far from his dwelling, and can employ his own time in getting it out. Though worth perhaps much less cord for cord when dry than hard wood, it may be cheaper for home consumption than fuel brought from a distance.

Various processes have been devised for preparing peat, with a view to bringing it into a condition of density and toughness, sufficient to obviate its usual faults, and make it compare with wood or even with coal in heating power.

The efforts in this direction have met with abundant success as regards producing a good fuel. In many cases, however, the cost of preparation has been too great to warrant the general adoption of these processes. We shall recur to this subject on a subsequent page, and give an account of the methods that have been proposed or employed for the manufacture of condensed peat fuel.

2.—Density of Peat.

The apparent[10] specific gravity of peat in the air-dry state, ranges from 0.11 to 1.03. In other words, a full cubic foot weighs from one-tenth as much as, to slightly more than a cubic foot of water, = 62-1/3 lbs. Peat, which has a specific gravity of but 0.25, may be and is employed as fuel. A full cubic foot of it will weigh about 16 lbs. In Germany, the cubic foot of "good ordinary peat" in blocks,[11] ranges from 15 to 25 lbs. in weight, and is employed for domestic purposes. The heavier peat, weighing 30 or more lbs. per cubic foot in blocks, is used for manufacturing and metallurgical purposes, and for firing locomotives.

Karmarsch has carefully investigated more than 100 peats belonging to the kingdom of Hanover, with reference to their heating effect. He classifies them as follows:—

A. Turfy peat, (Rasentorf,) consisting of slightly decomposed mosses and other peat-producing plants, having a yellow or yellowish-brown color, very soft, spongy and elastic, sp. gr. 0.11 to 0.26, the full English cubic foot weighing from 7 to 16 lbs.

B. Fibrous peat, unripe peat, which is brown or black in color, less elastic than turfy peat, the fibres either of moss, grass, roots, leaves, or wood, distinguishable by the eye, but brittle, and easily broken; sp. gr. 0.24 to 0.67, the weight of a full cubic foot being from 15 to 42 lbs.

C. Earthy peat.—Nearly or altogether destitute of fibrous structure, drying to earth-like masses which break with more or less difficulty, giving lustreless surfaces of fracture; sp. gr. 0.41 to 0.90, the full cubic foot weighing, accordingly, from 25 to 56 lbs.

D. Pitchy peat, (Pechtorf,) dense; when dry, hard; often resisting the blows of a hammer, breaking with a smooth, sometimes lustrous fracture, into sharp-angled pieces. Sp. gr. 0.62 to 1.03, the full cubic foot weighing from 38 to 55 lbs.

In Kane and Sullivan's examination of 27 kinds of Irish peat, the specific gravities ranged from 0.274 to 1.058.

3.—Heating power of peat as compared with wood and anthracite.

Karmarsch found that in absolute heating effect

100 lbs. of turfy, air-dry peat, on the average = 95 lbs. of pine wood. " fibrous " " " = 108 " " " earthy " " " = 104 " " " pitchy " " " = 111 " "

The comparison of heating power by bulk, instead of weight, is as follows:—

100 cubic ft. of turfy peat, on the average[12] = 33 cubic ft. of pine wood, in sticks. " " fibrous " " = 90 cubic ft. of pine wood, in sticks. " " earthy " " = 145 cubic ft. of pine wood, in sticks. " " pitchy " " = 184 cubic ft. of pine wood, in sticks.

According to Brix, the weight per English cord and relative heating effect of several air-dry peats—the heating power of an equal bulk of oak wood being taken at 100 as a standard—are as follows, bulk for bulk:[13]

Weight per Heating cord. effect. Oak wood 4150 lbs. 100 Peat from Linum, 1st quality, dense and pitchy 3400 " 70 " " 2d " fibrous 2900 " 55 " " 3d " turfy 2270 " 53 Peat from Buechsenfeld, 1st quality, pitchy, very hard and heavy 3400 lbs. 74 Peat from Buechsenfeld, 2d quality 2730 " 64

These statements agree in showing, that, while weight for weight, the ordinary qualities of peat do not differ much from wood in heating power; the heating effect of equal bulks of this fuel, as found in commerce, may vary extremely, ranging from one-half to three quarters that of oak wood.

Condensed peat may be prepared by machinery, which will weigh more than hard wood, bulk for bulk, and whose heating power will therefore exceed that of wood.

Gysser gives the following comparisons of a good peat with various German woods and charcoals, equal weights being employed, and split beech wood, air-dry, assumed as the standard.[14]

Beech wood, split, air dry 1.00 Peat, condensed by Weber's & Gysser's method,[15] air-dried, with 25 per cent. moisture. 1.00 Peat, condensed by Weber's & Gysser's method, hot-dried, with 10 per cent. moisture. 1.48 Peat-charcoal, from condensed peat. 1.73 The same peat, simply cut and air-dried. 0.80 Beech-charcoal. 1.90 Summer-oak wood. 1.18 Birch wood. 0.95 White pine wood. 0.72 Alder. 0.65 Linden. 0.65 Red pine. 0.61 Poplar. 0.50

Some experiments have been made in this country on the value of peat as fuel. One was tried on the N. Y. Central Railroad, Jan. 3, 1866. A locomotive with 25 empty freight cars attached, was propelled from Syracuse westward—the day being cold and the wind ahead—at the rate of 16 miles the hour. The engineer reported that "the peat gave us as much steam as wood, and burnt a beautiful fire." The peat, we infer, was cut and prepared near Syracuse, N. Y.

In one of the pumping houses of the Nassau Water Department of the City of Brooklyn, an experiment has been made for the purpose of comparing peat with anthracite, for the results of which I am indebted to the courtesy of Moses Lane, Esq., Chief Engineer of the Department.

Fire was started under a steam boiler with wood. When steam was up, the peat was burned—its quantity being 1743 lbs., or 18 barrels—and after it was consumed, the firing was continued with coal. The pressure of steam was kept as nearly uniform as possible throughout the trial, and it was found that with 1743 lbs. of peat the engine made 2735 revolutions, while with 1100 lbs. of coal it made 3866 revolutions. In other words, 100 lbs. of coal produced 351-45/100 revolutions, and 100 lbs. of peat produced 156-91/100 revolutions. One pound of coal therefore equalled 2-24/100 lbs. of peat in heating effect. The peat burned well and generated steam freely.

Mr. Lane could not designate the quality of the peat, not having been able to witness the experiment.

These trials have not, indeed, all the precision needful to fix with accuracy the comparative heating effect of the fuels employed; for a furnace, that is adapted for wood, is not necessarily suited to peat, and a coal grate must have a construction unlike that which is proper for a peat fire; nevertheless they exhibit the relative merits of wood, peat, and anthracite, with sufficient closeness for most practical purposes.

Two considerations would prevent the use of ordinary cut peat in large works, even could two and one-fourth tons of it be afforded at the same price as one ton of coal. The Nassau Water Department consumes 20,000 tons of coal yearly, the handling of which is a large expense, six firemen being employed to feed the furnaces. To generate the same amount of steam with peat of the quality experimented with, would require the force of firemen to be considerably increased. Again, it would be necessary to lay in, under cover, a large stock of fuel during the summer, for use in winter, when peat cannot be raised. Since a barrel of this peat weighed less than 100 lbs., the short ton would occupy the volume of 20 barrels; as is well known, a ton of anthracite can be put into 8 barrels. A given weight of peat therefore requires 2-1/2 times as much storage room, as the same weight of coal. As 2-1/4 tons of peat, in the case we are considering, are equivalent to but one ton of coal in heating effect, the winter's supply of peat fuel would occupy 5-5/8 times the bulk of the same supply in coal, admitting that the unoccupied or air-space in a pile of peat is the same as in a heap of coal. In fact, the calculation would really turn out still more to the disadvantage of peat, because the air-space in a bin of peat is greater than in one of coal, and coal can be excavated for at least two months more of the year than peat.

It is asserted by some, that, because peat can be condensed so as to approach anthracite in specific gravity, it must, in the same ratio, approach the latter in heating power. Its effective heating power is, indeed, considerably augmented by condensation, but no mechanical treatment can increase its percentage of carbon or otherwise alter its chemical composition; hence it must forever remain inferior to anthracite.

The composition and density of the best condensed peat is compared with that of hard wood and anthracite in the following statement:—

In 100 Carbon. Hydrogen. Oxygen and Ash. Water. Specific parts. Nitrogen. Gravity. Wood, 39.6 4.8 34.8 0.8 20.0 0.75 Condensed peat 47.2 4.9 22.9 5.0 20.0 1.20 Anthracite 91.3 2.9 2.8 3.0 1.40

In combustion in ordinary fires, the water of the fuel is a source of waste, since it consumes heat in acquiring the state of vapor. This is well seen in the comparison of the same kind of peat in different states of dryness. Thus, in the table of Gysser, (page 97) Weber's condensed peat, containing 10 per cent. of moisture, surpasses in heating effect that containing 25 per cent. of moisture, by nearly one-half.

The oxygen is a source of waste, for heat as developed from fuel, is chiefly a result of the chemical union of atmospheric or free oxygen, with the carbon and hydrogen of the combustible. The oxygen of the fuel, being already combined with carbon and hydrogen, not only cannot itself contribute to the generation of heat, but neutralizes the heating effect of those portions of the carbon and hydrogen of the fuel with which it remains in combination. The quantity of heating effect thus destroyed, cannot, however, be calculated with certainty, because physical changes, viz: the conversion of solids into gases, not to speak of secondary chemical transformations, whose influence cannot be estimated, enter into the computation.

Nitrogen and ash are practically indifferent in the burning process, and simply impair the heating value of fuel in as far as they occupy space in it and make a portion of its weight, to the exclusion of combustible matter.

Again, as regards density, peat is, in general, considerably inferior to anthracite. The best uncondensed peat has a specific gravity of 0.90. Condensed peat usually does not exceed 1.1. Sometimes it is made of sp. gr. 1.3. Assertions to the effect of its acquiring a density of 1.8, can hardly be credited of pure peat, though a considerable admixture of sand or clay might give such a result.

The comparative heating power of fuels is ascertained by burning them in an apparatus, so constructed, that the heat generated shall expend itself in evaporating or raising the temperature of a known quantity of water.

The amount of heat that will raise the temperature of one gramme of water, one degree of the centigrade thermometer, is agreed upon as the unit of heat.[16]

In the complete combustion of carbon in the form of charcoal or gas-coal, there are developed 8060 units of heat. In the combustion of one gramme of hydrogen gas, 34,210 units of heat are generated. The heating effect of hydrogen is therefore 4.2 times greater than that of carbon. It was long supposed that the heating effect of compound combustibles could be calculated from their elementary composition. This view is proved to be erroneous, and direct experiment is the only satisfactory means of getting at the truth in this respect.

The data of Karmarsch, Brix, and Gysser, already given, were obtained by the experimental method. They were, however, made mostly on a small scale, and, in some cases, without due regard to the peculiar requirements of the different kinds of fuel, as regards fire space, draught, etc. They can only be regarded as approximations to the truth, and have simply a comparative value, which is, however, sufficient for ordinary purposes.

The general results of the investigations hitherto made on all the common kinds of fuel, are given in the subjoined statement. The comparison is made in units of heat, and refers to equal weights of the materials experimented with.