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402

IMPROVED MODES OF PREPARING CHARCOAL.

IMPROVED MODES OF PREPARING

CHARCOAL.

(From the American Railroad Journal.) In consequence of the great waste of charcoal, in the usual mode of preparation, and the entire loss of the volatile matter, two modes have been contrived, in either of which the quantity of charcoal obtained may be almost as large as in iron cylinders, and the volatile matters may be collected.

The first of these is best suited to the hard woods which contain but little sesinous, matter. This operation is performed in a kiln of the shape of a cylinder, or rather a truncated cone, whose larger base is uppermost. It may be built of sods or tenacious earth above the natural surface of the soil, but may be more conveniently excavated to such a depth that the earth thrown out may serve to form the upper part of the enclosure. In the only instance in which we have seen it employed in this_country, namely, at the West Point Foundry, the excavation is lined with brick.

In order to admit air to the kiln, when made by excavation, for the purpose of maintaining the combustion, tnbes of earthenware or cast iron are carried down from the surface of the ground to the bottom of the excavation; these lie behind the lining, and are either passed through it near the bottom, or enter small brick vaults, which communicate with the interior of the kiln. The kiln may be closed at top by a cover made of sheet iron, to support which, when the lining is not of brick, a ring of bricks must be placed around the top of the excavation. The cover must extend on all sides three or four inches beyond the opening of the kiln, in order to have a sufficient support. In this cover there are several openings, one at the centre, the others near the circumference. Through each of these a short tube or flue of sheet iron passes, and the several tubes are furnished with stoppers of iron.

The size described by Dumas is ten feet (French) in diameter, and nine feet deep. The central tube is nine inches in diameter. The number of these at the circumference is four, each four inches in diameter.

That used at the West Point Foundry is twelve feet in diameter and nine feet deep.

In order to condense the volatile matter, one opening is made in the lining near the top of the kiln, to which a tube of cast iron or earthenware is applied. This tube communicates with a small chamber built of brick, about eighteen inches long, a foot in width, and fifteen inches high, entering about the middle of its height. From the top of this chamber proceeds a pipe of sheet iron, which after rising vertically four or five feet, assumes a horizontal direction for about fifteen feet more; at at this distance there is no fear of fire, and the rest of the pipe may be of wood. The extension of the pipe communicates with a condensing apparatus, on the principle of Woolf, but which may be formed of common barrels.

In charging the kiln with wood, a post whose height is equal to the depth of the excavation is set up in the middle, and supported in its place by a heap of fragments of charcoal. A number of the larger logs are chosen and laid on the bottom of the kiln in such a manner as to form rudiating flues, terminating at the places when the air tubes pass through the lining. Across these a horizontal layer of logs is laid. The radiating logs must neither touch the post or the lining of the kiln; the secondary layers extend from the one to the other. Layers are then placed in succession in such a manner as to leave as little empty space as possible, particularly near the circumference, until the kiln is filled. The kiln having been charged, the post is drawn out of the middle, the cover set in its place, and coated to the depth of not less than two inches with dry earth.

The stoppers being withdrawn from the flues in the cover, lighted charcoal is poured down through the middle tube; this falls through the space left by the post, to the heap of charcoal by which it was steadied, and sets it on fire. The central flue is then tightly closed, in order that the draught may be directed towards the outside of the mass of wood. In order to make the joint of the stopper tight, it is luted with plastic clay. The other flues begin to discharge smoke, which is surrounded

IMPROVED MODES OF PREPARING CHARCOAL.

by flame. As soon as the flame ceases to have a blue colour, and becomes white and clouded, the flues have their stoppers loosely applied to them, and the openings of the descending air tubes are diminished. The draught will thus be directed to the condensing apparatus. But if the collection of the acid be not intended, the tubes in the cover are but partially closed. The combustion may be regulated within the kiln by the air tubes and those in the cover. Thus, too rapid an action in any one part may be checked by completely closing the several air tubes and the opposite flue; and if it be too slow, these must be opened as far as possible until the action be restored.

For a kiln ten by nine, the operation occupies from sixty to eighty hours, and is known to be complete when the upper layer of wood appears to be incandescent; when this has taken place, the stoppers of all the openings except that of the central flue are removed for a short time, and a quantity of hydrogen will be expelled, which, if it does not injure the quantity of charcoal, would render it less saleable.

As soon

as the peculiar flame of hydrogen ceases, all the openings, both of the air tubes and Alues, must be closed by shutting their stoppers with clay, and covering them with caps of sheet iron containing clay. The dry earth is removed from the cover, and it is plastered with earth mixed with water. The charcoal thus shut up will take sixty to eighty hours to cool.

A plan and section of this description of kiln is represented in fig. 1, 2, 3, 4,

and 5.

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403

At the Bennington furnace, a kiln of similar form was constructed of brick, above the level of the ground, and covered by a permanent dome of brick. In the wall a door was left for the introduction of the wood, and this was subsequently bricked up. Vents were formed by leaving bricks loose in the wall, and when the process was complete, the fire was extinguished by means of water. An unexpected benefit was found to arise from the latter operation; for the coal becoming charged with aqueous vapour, was as fit for immediate use, as that which had been prepared for several months.

It is estimated that the product of kilns of this kind in France, is about 25 per cent. more than in a coal-pit. The experiment at the West Point Foundry was more advantageous, the product having 50 per cent. more than was obtained in the usual method. In France the main object was the pyrolignous acid; which at West Point was neglected; and this difference in the object will account for the difference in the results. The mode of placing the wood was also different; the French using that which has been described above, while at the West Point it was placed vertically.

In the pine forests of Sweden, an ap paratus better suited to the collection of the turpentine that kind of wood furnishes, has been invented by Schwartz. This kiln is composed of a vault, built of brick or siliceous stone laid in a mixture of clay and sand. Common mortar must not be used, as it would not only be effected by the heat, but would be completely destroyed by the pyrolignous acid. The vault is closed at each end by a vertical wall of the same kind of masonry. The floor of the kiln is of earth, and has the figure of two planes slightly inclined, and meeting in a gutter in the middle of the longer sides of the vault. In each end wall are two fire places, and in one of them are four openings for introducing the wood and withdrawing the charcoal. The smoke and vapour are carried off by flues of cast iron at the level of the ground, and proceeding from the middle of the larger sides of the vault; these minate in channels where the vapour is condensed, and which convey the smoke

404

PROPOSALS FOR INTRODUCING SALMON INTO THE RIVERS OF FRANCE.

to two vertical chimneys. A section of this kiln is represented in fig. 6.

The advantage of this arrangement is, that no air can enter the kiln without passing through the fire-places which are kept full of burning fuel; and that the fuel which is best suited for this purpose (small branches and twigs), is useless in making charcoal. In placing the wood, the pieces are laid parallel to the largest sides of the vault, and in such manner as to leave as little space as possible except in the neighbourhood of the flues, which must be kept free for the escape of smoke and vapour. Two days are sufficient to convert the wood into charcoal, and the end of the process is known by the appearance of the blue flame of carburetted hydrogen at the chimneys. The whole of the openings are then closed, and with luted clay.

At the end of two days, two holes, left for the purpose in the arch of the vault, but which have during the process been carefully closed, are opened, and water thrown in to cool the charcoal; these holes are then closed again. At the end of three or four days more, one of the doors in the end wall is opened, and more water thrown in ; but the charcoal will not be ready to be removed, until all the external parts of the apparatus have become as cold as the surrounding air.

This kind of furnace has been much used in Europe, and the quantity of charcoal obtained is one-third more than is obtained from coal-pits. The turpentine and arcetic acid are also saved, which in other cases are lost. There can be no doubt that it might be introduced to advantage in those parts of our country where iron is manufactured by means of charcoal prepared from pine wood.

In using kilns of either description, it becomes a matter of calculation whether it be cheaper to manufacture the charcoal in the woods in the usual manner, or to carry the wood to the kiln. The weight of the charcoal to be transported will be only seventeen parts of that of the wood; while the charcoal obtained by the kilns will be certainly one-third more than that procured from the pits. It must therefore appear that the value of the addi

tional charcoal shall be at least equiva lent to the cost of transporting the wood to the kiln. It is also to be remarked, that charcoal prepared on the spot where it is to be used is better than that which has here been handled and carried over rough roads, and that all waste is avoided.

THE BRITISH SALMON FIHERIES, WITH
PROPOSAL FOR THE INTRODUCTION
RIVERS OF
SALMON INTO THE

OF

FRANCE.

Sir,-Although the following communication does not immediately apply to the extension of any merely British source of industry and utility, yet, as it may convey a useful hint to our neighbours, I think you will afford it a place in your widely-circulating miscellany, in deference to the maxims so well and philosophically expressed in the lines of Pope:

"Self-love but serves the virtuous mind to wake, As the small pebble stirs the peaceful lake; The centre moved, a circle first succeeds, Another still, and still another breeds; Parent, friend, neighbour, first it does embrace, Our country next, and next all human race." This is the maxim and rule of action. But it is not impossible that some Englishman, or Englishmen, might take advantage of my suggestion, and turn it to good industrial account, by application to the French Government.

"Translation of a Letter addressed to Count Martignac, Minister of the Interior to the King of France, dated 24th of March, 1828, and Duplicate sent 20th of January, 1829.*

"Excellence,-I have often contemplated with satisfaction, the great advantages which would result to that part of France situated at the mouth and along the course of the Rhone, if salmon were introduced into that beautiful river, which possesses advantages above any other in Europe for the propagation and supply of that valuable fish.

"Salmon do not frequent the seas or rivers of warm latitudes: they delight in a rather cold climate. In Europe, the most southern limits of their visits are the rivers of the north of Spain, in the 44th degree of latitude. No salmon are found in the Mediterranean, because, as they do not exist in the Black Sea, they can only come from the Atlantic Ocean; and in order to get admittance by the only inlet on that side, they

No answer returned:

PROPOSALS FOR INTRODUCING SALMON INTO THE RIVERS OF FRANCE. 405

would have to descend southward to the Straits of Gibraltar, which, being in latitude 36°, is beyond the limits of their southern migrations. The mouth of the Rhone is in the same degree of latitude as the river of St. Andre, where I have found salmon to abound, that is, in 440; and the waters of the Lake of Geneva, and of the little rivers that flow into it, which may be called, as regards the salmon, the terminus of the Rhone, are pretty nearly of a similar temperature with the Scotch and Irish rivers, which they so much frequent.

"Several of the salmon fisheries established on the Tweed, the Tyne, the Shannon, and the Eden, produce an annual revenue of 5000l., 70007., 10,000l., and 12,0002. a year to the proprietors. Near the mouth of the river Eden, as many as 882,000 large salmon have been taken in 72 days.

"The propagation of fresh-water fish, which is somewhat attended to in districts remote from the sea, can never become an object of national importance, or of extensive sustenance, because such fish, as trout, pike, perch, and eels, being fish of prey, can never be produced in a lake, or pond, or river, beyond the number that can be supported by the small fish on which they live, that are furnished by the same confined waters, for their sustenance. Carp and tench may be fed on grain, &c.; but salmon are fed gratis on the vast stores of the extensive ocean. After the salmon has gained a rapid growth -through the inexhaustible store of food, which he knows where to find in the sea-he returns to our shores; ascends the rivers; penetrates into the interior of nations; mounts up to the very sources of the streams on the highest table-lands, and gives himself up, well fattened at the expense of the ocean, to people who, perhaps, know little of the sea, but from the rich tribute which it thus annually sends them.

"I do not here propose to address to your Excellency a regular treatise on the habits and natural history of the salmon; but it is necessary that I should remind you of the fact, that this fish returns periodically, with entire constancy during the whole of its life, to the river which gave it birth; and that whenever any number of salmon were let free, in an appropriate river, during the season which precedes their spawning, there I would not be one of them that would not hasten to mount against the stream until it -had found a fitting place to stop and deposit - its eggs.

"Salmon begin to enter the rivers of Scotland and Ireland, more or less, about the month of April; it is, however, in June and July that the greatest quantity arrive. It is immediately after its arrival from the sea, in

which it has been long living on abundant and nourishing food, that the salmon is in perfection. Its flesh is then of a bright,

deep red colour; but in proportion to its sojourn in the fresh water of the rivers, in which it, comparatively, eats nothing, and as the time of its spawning approaches-it deteriorates in quality from day to day, its beautiful colour fades by little and little into a dirty yellow, its delicious flavour is lost and becomes flat and disgusting, its firm and solid flesh becomes flaccid and almost gelatinous, and an hitherto wholesome and nourishing article of food has become pernicious and disagreeable.

"The ovarie of a female salmon, of the age of four or five years, contains generally rather more than 600.000 eggs. It appears that, at variance with the habits of many other fishes, one male only is attached to one female. About the month of December, the former aids the latter in digging with the nose a furrowed bed in the gravel, in which furrows the female deposits her eggs. The male then completes the work, and covers the eggs over with gravel, as a gardener would a drill of spinach. According to the season, but generally about the beginning of March, the eggs begin to hatch; the first appearance of which most closely resembles that of a bed of onions just beginning to grow. The shells of the eggs and the heads of the fry being still engaged in the gravel, the tails are seen standing up erect for several days before the detachment occurs.

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"I beg to assure your Excellency, that on this subject I can speak from some experience. I am much addicted to angling, have caught many salmon with the hook and line, and have had many opportunities of personally observing their habits. To another point, also, I have paid much attention, and that is, to the best method of keeping fish alive, and transporting them to a distance. I furnished a curious instance of this knowledge, on behalf of the late King of Naples, when I had the honour to be one of the Captains of the Chase.' With the particulars of this procedure, which was much noticed by men of science at Naples, I will not trouble your Excellency; but I will only state, that I can point out a sure and cheap method by which 50 male and 50 female salmon may be conveyed, either from a Scotch or French salmon fishery, and turned out alive, safe and sound, into the Rhone, somewhere about Avignon. As sure as that a stone thrown up into the air will fall again to the earth, so surely will the salmon so turned out immediately betake themselves to ascend the stream, and in due time deposit their eggs in the Lake of Geneva, and its innumerable ingressing rivulets, localities pos

406

ELECTRICAL THEORY OF THE UNIVERSE.

sessing advantages and capacity for that purpose greater than all the rivers of Scotland and Ireland put together!

"At the rate of only 100,000 fry, produced by each female salmon introduced, we should have 5,000,000 of fry, without reckoning that the original fish would return (barring accidents) to the same river to lay their eggs the next year, and so on in succession to the end of their lives.

"The young salmon hatched in March go down to the sea in September. They return next March, to stay only till July, when they weigh from 2 to 4lbs; next spring they return again, of the weight of from 6 to 10lbs.; and the third year, they weigh from 15 to 25lbs.

"Thus at the expiration of three years the produce of the first spawning, weighing from 15 to 25lbs., would begin to breed at the rate of 500,000 each; and then a commencement might be allowed to the fishery, which in such a river, and conducted under proper regulations, would in all probability yield not less than 1,000,000 francs (40,0007.) annually!

"The British salmon fisheries would undoubtedly produce more than ten times what they do, were the laws which are intended to protect the propagation of the salmon better digested, and, above all, better enforced. There are numerous Acts of Parliament on the subject, all pulling one against the other. A penalty is enforced against the taking of salmon, but none against its public exposure for sale during the prohibited periods. The sale of hares, partridges, &c. is punished; but a matter of national interest is neglected, as beneath the notice of our hare-killing legislators! One river has one law; a second has another; and so has a third! It is unlawful to take salmon at the mouth of some rivers with what are called stake-nets (which, by-the-bye, under due restrictions, is the best plan), and in others it is the only way pursued! In fine, there is no well-digested law in England on the subject. In some districts remote from the sea, almost every female salmon is speared by the peasantry when in the act of spawning; and no punishment is awarded to the wholesale destroyer, who obtains nothing but poisonous food for his pains. Should your Excellency do me the honour to reply to this communication, and require my suggestions, I shall be able to lay before you a well-reasoned and clear statement of the laws and regulations which ought to be enacted on the subject of salmon fisheries; and also on other fisheries in general, not forgetting that of oysters, which is sadly mismanaged, both in England and France.

"There is not a doubt but that when once

salmon shall become indigenous in the Rhone, the surplus population' of these colonists will spread far and wide, and, by degrees, populate or salmonate all the rivers that fall into the Gulf of Lyons, and of the Mediterranean in general. It has been said most justly, that eternal honour would be due to him who should cause two blades of grass to grow where only one had thriven before.' Not only posterity, but the present generation, will have cause to bless the name of your Excellency, if, by your instrumentality and patronage, a vast, gratuitous, and unlookedfor supply of delicious human food is wrested from the bosom of the ocean for the daily benefit of thousands of your countrymen.

"The expense of carrying into effect the useful introduction I have suggested to your Excellency, would not exceed 40,000 or 50,000 francs. Should it be undertaken by an individual or by a Company, it would be well worth while for the Government, on the ground of national utility, to grant a special privilege of the fishery within a certain distance from the mouth of the river, of ten or fifteen years, beginning from the third year after the introduction of the salmon.

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"I have the honour to be, your Excellency's humble and obedient servant, "F. MACERONI, "Officer of the Legion of Honour, &c. "London, March 23, 1828."

ELECTRICAL THEORY OF THE UNIVERSE -REALITY OF AN ELECTRIC FLUID.

Sir, I beg to forward to you the following remarks on "Mr. Mackintosh's Theory of the Universe," more particularly in reference to Kinclaven's communication in No. 682. I shall confine myself to one point of the controversy,viz. that respecting the materiality of what is termed the electric fluid, which Kinclaven seems to call in question, quoting as his authority, what he most appropriately terms some "remarkable observations" of Sir John Leslie's.

Before, however, I proceed fairly to discuss the point, I will candidly express my opinion, an opinion formed from a perusal of Kinclaven's communications, that he is, himself, too much of a mathematician to entertain any doubt in his own mind upon the subject, notwithstanding the ipse dixit of a philosopher, whose opinion must claim the attention, even of those who differ from him; and that, consequently, Kinclaven has made use of these truly remarkable observations of Sir John Leslie's, solely for the

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