Chapter 8

Fig. 20.Fig. 20.—VERSMANN'S PEAT PULVERIZER.

Fig. 20.—VERSMANN'S PEAT PULVERIZER.

Versmann's Machine[28]—This machine, see Fig. 20, was invented by a German engineer, in London, and was patented there in Sept., 1861. It consists of a funnel or hollow coneb, of boiler-plate, from one to two feet in diameter at top, and perforated with 200 to 300 small holes per square foot of surface, within which rapidly revolves an iron conea, carrying on its circumference two spiral knives. The peat thrown in at the top of the funnel is carried down by the knives, and at once cut or broken and forced in a state of fine division through the holes of the funnel, as through a colander. The fine peat collects on the inclined bottom of the chamberd, whence it is carried by means of Archimedean screws to a moulding machine. The coarse stuff that escapes pulverization falls througheinto the cavityc. It may be employed as fuel for the engine, or again put through the machine.

This machine effects a more perfect pulverization of the peat, than any other hitherto described. This extreme division is, however, unnecessary to the perfection of the product, and is secured at great expense of power. Through the opening at the bottom of the funnel, much unpulverized peat finds its way, which must be continually returned to the machine. Again, stones, entering the funnel, are likely to break or damage the spiral knives, which bear close to the walls of the funnel.

The pulverized peat must be moulded by hand, or by a separate instrument.

Buckland's Machine[29]is identical in principle with Versmann's, and in construction differs simply in the fact of the interior cone having spiral grooves instead of spiral knives. This gives greater simplicity and durability to the machine. It appears, however, to require too much power to work it, and can hardly equal other machines in the quantity of product it will deliver for a given expenditure. The ground peat yielded by it, must be moulded by hand, or by other machinery. This machine, we understand, has been tried near Boston, and abandoned as uneconomical.

The machines we have described are by no means all that have been proposed and patented. They include, however, so the author believes, all that have been put into actual operation, at the date of this writing, or that present important peculiarities of construction.

The account that has been given of them will serve to illustrate what mechanism has accomplished hitherto in the manufacture of peat-fuel, and may save the talent of the American inventor from wasting itself on what is already in use, or having been tried, has been found wanting. At present, very considerable attention is devoted tothe subject. Scarcely a week passes without placing one or more Peat-mill patents on record. In this treatise our business is with what has been before the public in a more or less practical way, and it would, therefore, be useless to copy the specifications of new, and for the most part untried patents, which can be found in the files of our mechanical Journals.

14.Artificial Drying of Peat.

As we have seen, air-dry peat contains 20 to 30 and may easily contain 50per cent.of water, and the best hot-made machine peat contains 15per cent.When peat is used as fuel in ordinary furnaces, this water must be evaporated, and in this process a large amount of heat is consumed, as is well understood. It is calculated, that the temperature which can be produced in perfectly burning full-dried peat, compares with that developed in the combustion of peat containing water, as follows:—

Pyrometric effect of perfectly dry peat4000° F.Pyrometric effect of peat with 30per cent.of water3240° F.Pyrometric effect of peat with 50per cent.of water2848° F.

But, furthermore, moist or air-dried peat does not burn in ordinary furnaces, except with considerable waste, as is evident from the smokiness of its flame. When air-dried peat is distilled in a retort, a heavy yellow vapor escapes for some time after the distillation begins, which, obviously, contains much inflammable matter, but which is so mixed and diluted with steam that it will not burn at all, or but imperfectly. It is obvious then, that when a high temperature is to be attained, anhydrous or full-dried peat is vastly superior to that which has simply been cured in the open air.

Notice has already been made of Weber's drying-house, the use of which is an essential part of his system of producing peat-fuel. Various other arrangements havebeen proposed from time to time, for accomplishing the same object. It appears, however, that in most cases the anticipations regarding their economy have not been fully realized. It is hardly probable, that artificially dried peat can be employed to advantage except where waste heat is utilized in the operation.

A point of the utmost importance in reference to the question of drying peat by artificial warmth is this, viz.: Although the drying may be carried so far as to remove the whole of the water, and produce an absolutely dry fuel, the peat absorbs moisture from the air again on exposure; so that drying to less than 15per cent.of water is of no advantage, unless the peat is to be used immediately, or within a few days. The employment of highly dried peat is consequently practicable only for smelting-works, locomotives, and manufacturing establishments, where it may be consumed as fast as it is produced.

A fact likewise to be regarded is, that artificial drying is usually inapplicable to fresh peat. The precautions needful in curing peat have already been detailed. Above all, slow drying is necessary, in order that the blocks shrink uniformly, without cracking and warping in such a way as to seriously injure their solidity and usefulness. In general, peat must be air-dried to a considerable extent before it can be kiln-dried to advantage. If exposed to dry artificial heat, when comparatively moist, a hard crust is formed externally, which greatly hinders subsequent desiccation. At the same time this crust, contracting around the moist interior, becomes so rifted and broken, that the ultimate shrinkage and condensation of the mass is considerably less than it would have been had the drying proceeded more slowly.

Besides Weber's drying oven, the fuel for firing which is derived without cost from the stumps and roots of trees that are abundant on the moor, at Staltach, and whichare thus conveniently disposed of, we have briefly to notice several other drying kilns with regard to all of which, however, it must be remarked, that they can only be employed with profit, by the use of waste heat, or, as at Staltach, of fuel that is comparatively worthless for other purposes.

Fig. 21.Fig. 21.—CARINTHIAN PEAT DRYING-KILN.

Fig. 21.—CARINTHIAN PEAT DRYING-KILN.

ThePeat Kilnsemployed at Lippitzbach, in Carinthia, and at Neustadt, in Hanover, are of the kind shown in fig. 21. The peat with which the main chamber is filled, is heated directly by the hot gases that arise from a fire made in the fire-place at the left. These gases first enter a vault, where they intermingle and cool down somewhat; thence they ascend through the openings of the brick grating, and through the mass of peat to the topof the chamber. On their way they become charged with vapor, and falling, pass off through the chimney, as is indicated by the arrows. The draught is regulated by the damper on the top of the chimney. To manage the fire, so that on the one hand the chimney is sufficiently heated to create a draught, and on the other waste of fuel, or even ignition of the peat itself is prevented, requires some care.

InWelkner's Peat Kiln[30](fig. 22) the peat, previously air-dried, is exposed to a stream of hot air, until it is completely desiccated, and the arrangement is such, that air-dried peat may be thrown in at the top, and the hot-dried fuel be removed at the bottom, continuously.

In the cut,Arepresents the section of a wooden cylinder about 10 feet wide and 6-½ feet deep, which surmounts a funnel of iron plateA'. The mouth of the funnel is closed by a doorn; about 20 inches above the door the pipeB, which conducts hot air, terminates in the ringa a, through the holes in which,e e, it is distributed into the funnel filled with peat. The air is driven in by a blower, and is heated by circulating through a system of pipes, which are disposed in the chimney of a steam boiler. From time to time a quantity of dried peat is drawn off into the wagonD, which runs on rails, and a similar amount of undried peat is thrown in above.

According to Welkner, a kiln of the dimensions stated, which cost, about $1800 gold, is capable of desiccating daily ten tons of peat with 20per cent.of water, using thereby 2000 cubic feet of air of a temperature of 212° F. When the air is heated by a fire kept up exclusively for that purpose, 10per cent.of the dried peat, or its equivalent, is consumed in the operation. At the Alexis Smelting Works, near Lingen, in Hanover, this peat kilnfurnishes about half the fuel for a high furnace, in which bog iron ore is smelted. The drying costs but little, since half the requisite heat is obtained from the waste heat of the furnace itself.

Fig. 22.Fig. 22.—WELKNER'S PEAT DRYING KILN.

Fig. 22.—WELKNER'S PEAT DRYING KILN.

The advantages of this drying kiln are, that it is cheap in construction and working; dries gradually and uniformly; occupies little ground, and runs without intermission.

Other drying ovens are described in Knapp'sLehrbuchderChemischen Technologie, 3. Aufl. Bd. 1, Theil 1, pp. 178-9;Jahrbuch der Bergakademien SchemnitzundLeoben, 1860, p. 108, 1861, p. 55; Wagner'sJahresbericht der Chemischen Technologie, 1863, p. 748; Zerrenner'sMetallurgische Gasfeuerung in Oesterreich; Tunner'sStabeisen- und Stahlbereitung, 2. Auflage, Bd. I, pp. 23-25.

15.Peat Coal, or Coke.

When peat is charred, it yields a coal or coke which, being richer in carbon, is capable of giving an intenser heat than peat itself, in the same way that charcoal emits an intenser heat in its combustion than the wood from which it is made.

Peat coal has been and is employed to some extent in metallurgical processes, as a substitute for charcoal, and when properly prepared from good peat, is in no way inferior to the latter; is, in fact, better.

It is only, however, from peat which naturally dries to a hard and dense consistency, or which has been solidified on the principles of Challeton's and Weber's methods, that a coal can be made possessing the firmness necessary for furnace use. Fibrous peat, or that condensed by pressure, as in Exter's, Elsberg's, and the Lithuanian process, yields by coking or charring, a friable coal comparatively unsuited for heating purposes.

A peat which is dense as the result of proper mechanical treatment and slow drying, yields a very homogeneous and compact coal, superior to any wood charcoal, the best qualities weighing nearly twice as much per bushel.

Peat is either charred in pits and heaps, or in kilns. From the regularity of the rectangular blocks into which peat is usually formed, it may be charred more easily in pits than wood, since the blocks admit of closer packing in the heap, and because the peat coal is less inflammable than wood coal. The heaps may likewise be made much smaller than is needful in case of wood, viz.: six to eight feet in diameter, and four feet high. The pit is arrangedas follows: The ground is selected and prepared as for charcoal burning, and should be elevated, dry and compact. Three stout poles are firmly driven into the ground, so as to stand vertically and equi-distant from each other, leaving within them a space of six or eight inches. Around these poles the peats are placed endwise, in concentric rows to the required width and height, leaving at the bottom a number of air-channels of the width of one peat, radiating from the centre outwards. The upper layers of peat are narrowed in so as to round off the heap, which is first covered with dry leaves, sods, or moss, over which a layer of soil is thrown. Dry, light wood being placed at the bottom of the central shaft, it is kindled from one of the canals at the bottom, and the charring is conducted as is usual in making wood coal. The yield of coal ranges from 25 to 35per cent.of the peat by weight, and from 30 to 50per cent.by volume.

Gysser recommends to mould the peat for charring in the form of cylinders of 3 to 4 feet long, which, when dry, may be built up into a heap like wood.

A great variety of ovens or kilns have been constructed for coking peat.

At the Gun Factory of Oberndorf, in Wirtemberg, peat is charred in the kiln represented in the accompanying figure. The chamber is 9 feet high, and 5-½ feet in diameter. The oven proper,b b, is surrounded by a mantle of bricka a, and the space between,c c, is filled with sand. Each wall, as well as the space, is 15 inches in thickness, and the walls are connected by stonesd d, at intervals of three feet. Above the sole of the kiln, are three series of air holes, made by imbedding old gun barrels in the walls. The door, which serves to empty the kiln, is a plate of cast iron, the sides of its frame are wider than the thickness of the wall, and by means of a boarde, a boxmcan be made in front of the door, which is filledwith sand to prevent access of air. The peat is filled in throughi, a channel being arranged across the bottom of the kiln, from the doorf, for kindling. When the firing begins, the lowest air-holes andiare open. When, through the lower gun barrels, the peat is seen to be ignited, these are corked, and those above are opened. When the smoke ceases to escape above, all the openings are closed,m, is filled with sand,iis covered over with it, and the whole is left to cool. It requires about 8 to 9 days to finish the charring of a charge. Several kilns are kept in operation, so that the work proceeds uninterruptedly.

Fig. 23.Fig. 23.—OBERNDORFER PEAT CHARRING KILN.

Fig. 23.—OBERNDORFER PEAT CHARRING KILN.

Fig. 24.Fig. 24.—WEBER'S CHARRING FURNACE.—TRANSVERSE SECTION.

Fig. 24.—WEBER'S CHARRING FURNACE.—TRANSVERSE SECTION.

At Staltach, Weber prepares peat coal in a cylinder of sheet iron, which is surrounded by masonry. Below, it rests on a grating of stout wire. Above, it has a cover, that may be raised by a pulley and on one side is attached a small furnace, figure 24, the draught of which is kept up by means of a blower, or an exhauster, and the flame and hotgases from it,which contain no excess of oxygen, play upon the peat and decompose it, expelling its volatile portions without burning or wasting it in the slightest degree. The construction of the furnace, see fig. 24, is such, that the sticks of wood, which are employed for fuel, are supported at their ends on shoulders in the brick-work, and the draught enters the fire above instead of below. The wood is hereby completely consumed, and by regulating the supply of air ata(fig. 25) by a sliding cover, and atbby a register, the flame and current of air which enters the cylinder containing the peat, is intensely hot and accomplishes a rapid carbonization of the peat, but as beforestated, does not burn it. In this furnace the wood, which is cut of uniform length, is itself the grate, since iron would melt or rapidly burn out; and the coals that fall are consumed by the air admitted through c. The hot gases which enter the cylinder filled with peat near its top, are distributed by pipes, and, passing off through the grating at the bottom, enter the surrounding brick mantle. Before reaching the exhaustor, however, they pass through a cooler in which a quantity of tar and pyroligneous acid is collected.

Fig. 25.Fig. 25.—WEBER'S CHARRING FURNACE.—LONGITUDINAL SECTION.

Fig. 25.—WEBER'S CHARRING FURNACE.—LONGITUDINAL SECTION.

Weber's oven is 15 feet in diameter, and 3-½ feet high; 528 cubic feet of peat may be coked in it in the space of 15 hours. The wood furnace is 2 feet in section, and consumes for the above amount of peat 3-½ cwt. of wood. So perfectly are the contents of the iron cylinder protected from contact of oxygen, that a rabbit placed within it, has been converted into coal without the singeing of a hair; and a bouquet of flowers has been carbonized, perfectly retaining its shape. The yield of coal in Weber's oven is nearly 50per cent.of the peat by weight.

Whenever possible, charring of peat should be carried on, or aided by waste heat, or the heat necessary to coking should be itself economized. In manufacturing and metallurgical establishments, a considerable economy in both the drying and coking may often be effected in this manner.

On the bog of Allen, in Ireland, we have an example of this kind. Peat is placed in iron ovens in the form of truncated pyramids, the bottoms of which consist of movable and perforated iron plates. The ovens are mounted on wheels, and run on a rail track.

Five ovens filled with peat are run into a pit in a drying house, in which blocks of fresh peat are arranged for drying. Each oven is connected with a flue, and fire is applied. The peat burns below, and the heat generatedin the coking, warms the air of the drying house. When the escaping smoke becomes transparent, the pit in which the ovens stand is filled with water slightly above their lower edges, whereby access of air to the burning peat is at once cut off. When cool, the ovens are run out and replaced by others filled with peat. Each oven holds about 600 lbs. of peat, and the yield of coal is 25per cent.by weight. The small yield compared with that obtained by Weber's method, is due to the burning of the peat and the coal itself, in the draught of air that passes through the ovens.

The author has carbonized, in an iron retort, specimens of peat prepared by Elsberg's, Leavitt's, and Aschcroft and Betteley's processes. Elsberg's gave 35, the others 37per cent.of coal. The coal from Elsberg's peat was greatly fissured, and could be crushed in the fingers to small fragments. That from the other peats was more firm, and required considerable exertion to break it. All had a decided metallic brilliancy of surface.

16.—Metallurgical Uses of Peat.

In Austria, more than any other country, peat has been employed in the manufacture of iron. In Bavaria, Prussia, Wirtemberg, Hanover, and Sweden, and latterly in Great Britain, peat has been put to the same use. The general results of experience, are as follows:—

Peat can only be employed to advantage, when wood and mineral coal are expensive, or of poor quality.

Peat can be used in furnaces adapted for charcoal, but not in those built for mineral coal.

Good air-dry peat, containing 20 to 30per cent.of water, in some cases may replace a share of charcoal in the high furnace.

At Pillersee, in Austria, spathic iron ore has been reduced by a mixture of fir-wood charcoal, and air-dry peatin the proportions of three parts by bulk of the former to one of the latter. The use of peat was found to effect a considerable saving in the outlay for fuel, and enabled the production to be somewhat increased, while the excellence of the iron was in no way impaired. The peat was of the best quality, and was worked and moulded by hand.

When the ore is refractory and contains impurities that must be fluxed and worked off in slag, a large proportion of air-dry peat cannot be used to advantage, because the evaporation of the water in it consumes so much heat, that the requisite temperature is not easily attained.

At Achthal, in Bavaria, air-dry peat was employed in 1860, to replace a portion of the fir wood charcoal, which had been used for smelting an impure clay-iron-stone: the latter fuel having become so dear, that peat was resorted to as a make shift. Instead of one "sack," or 33 cubic feet of charcoal, 24 cubic feet of charcoal and 15 cubic feet of peat were employed in each charge, and the quantity of ore had to be diminished thereby, so that the yield of pig was reduced, on the average, by about 17per cent.In this case the quality of the iron, when worked into bar, was injured by the use of peat, obviously from an increase of its content of phosphorus. The exclusive use of air-dry peat as fuel in the high furnace, appears to be out of the question.

At Ransko, in Bohemia,kiln-dried peat, nearly altogether free from water, has been employed in a high furnace, mixed with but one-third its bulk of charcoal, and in cupola furnaces for re-melting pig, full-dried peat has been used alone, answering the purpose perfectly.

The most important metallurgical application of peat is in the refining of iron.

Dried peat is extensively used in puddling furnaces, especially in the so-called gas puddling furnaces, in Carinthia, Steyermark, Silesia, Bavaria, Wirtemberg, Sweden,and other parts of Europe. In Steyermark, peat has been thus employed for 25 years.

Air-dry peat is, indeed, also employed, but is not so well adapted for puddling, as its water burns away a notable quantity of iron. It is one of the best known facts in chemistry, that ignited iron is rapidly oxidized in a stream of water-vapor, free hydrogen being at the same time evolved.

In the high furnace,peat-coal, when compact and firm (not crumbly) may replace charcoal perfectly, but its cost is usually too great.

When peat or peat-coal is employed in smelting, it must be as free as possible from ash, because the ash usually consists largely of silica, and this must be worked off by flux. If the ash be carbonate of lime, it will, in most cases, serve itself usefully as flux. In hearth puddling, it is important not only that the peat or peat-coal contain little ash, but especially that the ash be as free as possible from sulphates and phosphates, which act so deleteriously on the metal. The notion that, in general, peat and peat charcoal are peculiarly adapted for the iron manufacture, because they are free from sulphur and phosphorus, is extremely erroneous. Not infrequently they contain these bodies in such quantity, as to forbid their use in smelting.

In the gas-puddling furnace, or in the ordinary reverberatory, impure peat may, however, be employed, since the ashes do not come in contact with the metal. The only disadvantage in the use of peat in these furnaces is, that the grates require cleaning more frequently, which interrupts the fire, and, according to Tunner, increases the consumption of fuel 8 to 10per cent., and diminishes the amount of metal that can be turned out in a given time by the same quantity.

Notwithstanding the interruption of work, it has been found, at Rothburga, in Austria, that by substitution of machine-made and kiln-dried peat for wood in the gas-puddling furnace, a saving of 50per cent.in the cost of bar iron was effected, in 1860. What is to the point, in estimating the economy of peat, is the fact that while 6.2 cubic feet of dry fir-wood were required to produce 100 lbs. of crude bar, this quantity of iron could be puddled with 4.3 cubic feet of peat.

In the gas furnace, a second blast of air is thrown into the flame, effecting its complete combustion; Dellvik asserts, that at Lesjœforss, in Sweden, 100 lbs. of kiln-dried peat are equal to 197 lbs. of kiln-dried wood in heavy forging. In an ordinary fire, the peat would be less effective from the escape of unburned carbon in the smoke.

In other metallurgical and manufacturing operations where flame is required, as well as in those which are not inconvenienced by the ingredients of its ash, it is obvious that peat can be employed when circumstances conspire to render its use economical.

17.—Peat as a source of illuminating gas.

Prof Pettenkofer, of Munich, was the first to succeed in making illuminating gas from wood; and peat, when operated according to his method, furnishes also a gas of good quality, though somewhat inferior to wood-gas in illuminating power.

It is essential, that well-dried peat be employed, and the waste heat from the retorts may serve in part, at least, for the drying.

The retorts must be of a good conducting material; therefore cast iron is better than clay. They are made of the [**symbol] form, and must be relatively larger than thoseused for coal. A retort of two feet width, one foot depth, and 8 to 9 feet length, must receive but 100 lbs. of peat at a charge.

The quantity of gas yielded in a given time, is much greater than from bituminous coal. From retorts of the size just named, 8000 to 9000 cubic feet of gas are delivered in 24 hours. The exit pipes must, therefore, be large, not less than 5 to 6 inches, and the coolers must be much more effective than is needful for coal gas, in order to separate from it the tarry matters.

The number of retorts requisite to furnish a given volume of gas, is much less than in the manufacture from coal. On the other hand, the dimensions of the furnace are considerably greater, because the consumption of fuel must be more rapid, in order to supply the heat, which is carried off by the copious formation of gas.

Gas may be made from peat at a comparatively low temperature, but its illuminating power is then trifling. At a red heat alone can we procure a gas of good quality.

The chief impurity of peat-gas is carbonic acid: this amounts to 25 to 30per cent.of the gas before purification, and if the peat be insufficiently dried, it is considerably more. The quantity of slaked lime that is consumed in purifying, is therefore much greater than is needed for coal-gas, and is an expensive item in the making of peat-gas.

While wood-gas is practically free from sulphur compounds and ammonia, peat-gas may contain them both, especially the latter, in quantity that depends upon the composition of the peat, which, as regards sulphur and nitrogen, is very variable.

Peat-gas is denser than coal-gas, and therefore cannot be burned to advantage except from considerably wider orifices than answer for the latter, and under slight pressure.

The above statements show the absurdity of judgingof the value of peat as a source of gas, by the results of trials made in gas works arranged for bituminous coal.

As to the yield of gas we have the following data, weights and measures being English:—

100 lbs. of peat of medium quality from Munich, gaveReissig303 cub. ft.100 lbs. of air-dry peat from Biermoos, Salzburg, gaveRiedinger305 cub. ft.100 lbs. of very light fibrous peat, gaveReissig379 to 430 cub. ft.100 lbs. of Exter's machine-peat, from Haspelmoor, gave367 cub. ft.

Thenius states, that, to produce 1000 English cubic feet of purified peat-gas, in the works at Kempten, Bavaria, there are required in the retorts 292 lbs of peat. To distil this, 138-½ lbs. of peat are consumed in the fire; and to purify the gas from carbonic acid, 91-½ lbs. of lime are used. In the retorts remain 117 lbs. of peat coal, and nearly 6 lbs. of tar are collected in the operation, besides smaller quantities of acetic acid and ammonia.

According to Stammer, 4 cwt. of dry peat are required for 1000 cubic feet of purified gas.

The quality of the gas is somewhat better than that made from bituminous coal.

18.—The examination of Peat as to its value for Fuel, begins with and refers to the air-dry substance, in which:

1.—Water is estimated, by drying the pulverized peat, at 212°, as long as any diminution of weight occurs. Well-dried peat-fuel should not contain more than 20per cent.of water. On the other hand it cannot contain less than 15per cent., except it has been artificially dried at a high temperature, or kept for a long time in a heated apartment.

2.—Ashis estimated by carefully burning the dry residue in 1. In first-rate fuel, it should amount to less than 3per cent.If more than 8per cent., the peat is thereby rendered of inferior quality, though peat is employed which contains considerably more.

3.—Sulphurandphosphorusare estimated by processes, which it would be useless to describe here. Only in case of vitriol peats is so much sulphur present, that it is recognizable by the suffocating fumes of sulphuric acid or of sulphurous acid, which escape in the burning. When peat is to be employed for iron manufacture, or under steam boilers, its phosphorus, and especially its sulphur, should be estimated, as they injure the quality of iron when their quantity exceeds a certain small amount, and have a destructive effect on grate-bars and boilers. For common uses it is unnecessary to regard these substances.

4.—The quantity ofcoalorcokeyielded by peat, is determined by heating a weighed quantity of the peat to redness in an iron retort, or in a large platinum crucible, until gases cease to escape. The neck of the retort is corked, and when the vessel is cool, the coal is removed and weighed. In case a platinum crucible is employed, it should have a tight-fitting cover, and when gases cease to escape, the crucible is quickly cooled by placing it in cold water.

Coal, or coke, includes of course the ash of the peat. This, being variable, should be deducted, and theash-free coalbe considered in comparing fuels.

5.—Thedensityof peat-fuel may be ascertained by cutting out a block that will admit of accurate measurement, calculating its cubic contents, and comparing its weight with that of an equal bulk of water. To avoid calculation, the block may be made accurately one or several cubic inches in dimensions and weighed. The cubic inch of water at 60° F., weighs 252-½ grains.

[10]The apparent specific gravity here means the weight of the mass,—the air-filled cavities and pores included—as compared with an equal bulk of water. The real specific gravity of thepeat itselfis always greater than that of water, and all kinds of peat will sink in water when they soak long enough, or are otherwise treated so that all air is removed.

[11]The "full" cubic foot implies a cubic foot having no cavities or waste space, such as exist in a pile, made up of numerous blocks. If a number of peat blocks be put into a box and shaken together, the empty space between the more or less irregular blocks, may amount to 46per cent.of the whole; and when closely packed, the cavities amount to 30per cent., according to the observations ofWasserzieher. (Dingler's Journal, Oct., 1864, p. 118.) Some confusion exists in the statements of writers in regard to this matter, and want of attention to it, has led to grave errors in estimating the weight of fuel.

[12]Thewaste spacein peat and wood as commonly piled, is probably included here in the statement, and is usually about the same in both; viz.: not far from 40per cent.

[13]See note on the preceding page.

[14]Der Torf, etc., S. 43.

[15]See page 00.

[16]On account of the great convenience of the decimal weights and measures, and their nearly universal recognition by scientific men, we have adopted them here. The gramme = 15 grains; 5 degrees centigrade = 9 degrees Fahrenheit.

[17]Pliny, Hist. Nat. (Lib. XVI, 1) expresses his pity for the "miserable people" living in East Friesland and vicinity in his day, who "dug out with the hands a moor earth, which, dried more by wind than sun, they used for preparing their food and warming their bodies:"captum manibus lutum ventis magis quam sole siccantis, terra cibos et rigentia septembrione viscera sua urunt.As regards the "misera gens," it should be said that rich grain fields and numerous flourishing villages have occupied for several centuries large portions of the Duevel moor near Bremen.

As regards the "misera gens," it should be said that rich grain fields and numerous flourishing villages have occupied for several centuries large portions of the Duevel moor near Bremen.

[18]For further account and plans of this machine see Dingler's Polytechnisches Journal, Bd. 176, S. 336.

[19]Described and figured in Bulletin de la Societe d'Encouragement, August 1857, p. 513; also Dingler's Polytechnisches Journal, Bd. 146, S. 252.

[20]Berg- und Huettenmænnische Zeitung, 1859, Nr. 26.

[21]Henneberg's Journal fuer Landwirthschaft, 1858, S. 42.

[22]Henneberg's Journal fuer Landwirthschaft, 1858, p.p. 42 and 83.

[23]Dingler's Journal, Oct., 1864.

[24]Dingler's Polytechnisches Journal, Bd. 152, S. 272. See also, Knapp, Lehrbuch der Chemischen Technologie, 3te Auflage, 1., 167.

[25]Der Torf; seine Bildung und Bereitungsweise, von Rudolph Gysser, Weimar, 1864.

[26]Dingler's Journal, Bd. 165, S. 184.; und Bd. 172, S, 333.

[27]Scientific American, Feb. 10, 1866; also, Facts about Peat as Fuel, by T. H. Leavitt, 2d Ed., Boston, p. 23.

[28]Dingler's Journal, Bd. 168, S. 306, und Bd. 172, S. 332.

[29]Described in Journal of the Society of Arts, 1860, p. 437.

[30]Bernemann & Kerl's Berg und Huettenmænnische Zeitung, 1862, 221.

Transcriber's NoteTypographical errors corrected in the text:Page 6 Robert's changed to Roberts'Page 24 Jaeckel changed to JæckelPage 47 Poquonnock changed to PoquonockPage 49 connexion changed to connectionPage 51 Poquonnock changed to PoquonockPage 53 Russel changed to RussellPage 53 Poquonnock changed to PoquonockPage 62 subtances changed to substancesPage 67 Poquonnock changed to PoquonockPage 89 5 changed to 4Page 89 Poquonnock changed to PoquonockPage 116 artifical changed to artificialPage 127 developes changed to developsPage 149 Kneeding changed to Kneading

Transcriber's Note

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