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Scientific American Supplement No. 360, November 25, 1882
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SCIENTIFIC AMERICAN SUPPLEMENT NO. 360



NEW YORK, NOVEMBER 25, 1882

Scientific American Supplement. Vol. XIV, No. 360.

Scientific American established 1845

Scientific American Supplement, $5 a year.

Scientific American and Supplement, $7 a year.

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TABLE OF CONTENTS.

I. ENGINEERING AND MECHANICS.—Soaking Pits for Steel Ingots. —On the successful rolling of steel ingots with their own initial heat by means of the soaking pit process. By JOHN GJERS. 6 figures.—Gjers' soaking pits for steel ingots.

Tempering by compression.—L. Clemandot's process.

Economical Steam Power. By WILLIAM BARNET LE VAN.

Mississippi River Improvements near St. Louis, Mo.

Bunte's Burette for the Analysis of Furnace Gases. 2 figures.

The "Universal" Gas Engine. 8 figures.—Improved gas engine.

Gas Furnace for Baking Refractory Products. 1 figure.

The Efficiency of Fans. 5 figures.

Machine for Compressing Coal Refuse into Fuel. 1 figure.— Bilan's machine.

Hank Sizing and Wringing Machine. 1 figure.

Improved Coke Breaker. 2 figures.

Improvements in Printing Machinery. 2 figures.

II. TECHNOLOGY AND CHEMISTRY.—Apparatus for Obtaining Pure Water for Photographic Use. 3 figures.

Black Phosphorus.—By P THENARD.

Composition of Steep Water

Schreiber's Apparatus for Revivifying Bone Black. 5 figures.— Plant: elevation and plan.—Views of elevation.—Continuous furnace.

Soap and its Manufacture from a Consumer's Point of View. (Continued from SUPPLEMENT, No. 330).

Cotton seed Oil.—By S. S. BRADFORD.

On some Apparatus that Permit of Entering Flames.—Chevalier Aldini's wire gauze and asbestos protectors.—Brewster's account of test experiments.

III. ELECTRICITY, LIGHT. ETC.—On a New Arc Electric Lamp. By W. H. PREECE. 6 figures—The Abdank system.—The lamp.— The Electro-magnet.—The Cut-off.—The electrical arrangement.

Utilization of Solar Heat.

IV. NATURAL HISTORY.—The Ocellated Pheasant. 1 figure.

The Maidenhair Tree in the Gardens at Broadlands, Hants, England. 1 figure.

The Woods of America.—The Jessup collection in the American Museum of Natural History, Central Park, and the characteristics of the specimens.

V. AGRICULTURE, ETC.—An Industrial Revolution.—Increase in the number of farms.

A Farmer's Lime Kiln. 3 figures.

The Manufacture of Apple Jelly.

Improved Grape Bags. 4 figures.

VI. ARCHITECTURE, ETC.—The Building Stone Supply.—Granite and its sources.—Sandstone.—Blue and gray limestone.—Marble.— Slate.—Other stones.—A valuable summary of the sources and uses of quarry products.

VII. ASTRONOMY. ETC.—How to Establish a True Meridian. By Prof. L. M. HAUPT.—Introduction.—Definitions.—To find the azemuth of Polaris.—Applications, etc.

VIII. MISCELLANEOUS.—A Characteristic Mining "Rush."—The Prospective Mining Center of Southern New Mexico.

The Food and Energy of Man. By Prof. DE CHAUMONT.—Original food of man.—Function of food.—Classes of alimentary substances.—Quantity of food.—Importance of varied diet.

Rattlesnake Poison.—Its Antidotes. By H. H. CROFT.

The Chinese Sign Manual.—The ethnic bearing of skin furrows on the hand.

Lucidity.—Matthew Arnold's remarks at the reopening of the Liverpool University College and School of Medicine.

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SOAKING PITS FOR STEEL INGOTS.

ON THE SUCCESSFUL ROLLING OF STEEL INGOTS WITH THEIR OWN INITIAL HEAT BY MEANS OF THE SOAKING PIT PROCESS.

By Mr. JOHN GJERS, Middlesbrough.

[Footnote: Paper read before the Iron and Steel Institute at Vienna.]

When Sir Henry Bessemer, in 1856, made public his great invention, and announced to the world that he was able to produce malleable steel from cast iron without the expenditure of any fuel except that which already existed in the fluid metal imparted to it in the blast furnace, his statement was received with doubt and surprise. If he at that time had been able to add that it was also possible to roll such steel into a finished bar with no further expenditure of fuel, then undoubtedly the surprise would have been much greater.

Even this, however, has come to pass; and the author of this paper is now pleased to be able to inform this meeting that it is not only possible, but that it is extremely easy and practical, by the means to be described, to roll a steel ingot into, say, a bloom, a rail, or other finished article with its own initial heat, without the aid of the hitherto universally adopted heating furnace.

It is well understood that in the fluid steel poured into the mould there is a larger store of heat than is required for the purpose of rolling or hammering. Not only is there the mere apparent high temperature of fluid steel, but there is the store of latent heat in this fluid metal which is given out when solidification takes place.

It has, no doubt, suggested itself to many that this heat of the ingot ought to be utilized, and as a matter of fact, there have been, at various times and in different places, attempts made to do so; but hitherto all such attempts have proved failures, and a kind of settled conviction has been established in the steel trade that the theory could not possibly be carried out in practice.

The difficulty arose from the fact that a steel ingot when newly stripped is far too hot in the interior for the purpose of rolling, and if it be kept long enough for the interior to become in a fit state, then the exterior gets far too cold to enable it to be rolled successfully. It has been attempted to overcome this difficulty by putting the hot ingots under shields or hoods, lined with non-heat-conducting material, and to bury them in non-heat-conducting material in a pulverized state, for the purpose of retaining and equalizing the heat; but all these attempts have proved futile in practice, and the fact remains, that the universal practice in steel works at the present day all over the world is to employ a heating furnace of some description requiring fuel.

The author introduced his new mode of treating ingots at the Darlington Steel and Iron Company's Works, in Darlington, early in June this year, and they are now blooming the whole of their make, about 125 tons a shift, or about 300 ingots every twelve hours, by such means.

The machinery at Darlington is not adapted for rolling off in one heat; nevertheless they have rolled off direct from the ingot treated in the "soaking pits" a considerable number of double-head rails; and the experience so gained proves conclusively that with proper machinery there will be no difficulty in doing so regularly. The quality of the rails so rolled off has been everything that could be desired; and as many of the defects in rails originate in the heating furnace, the author ventures to predict that even in this respect the new process will stand the test.

Many eminently practical men have witnessed the operation at Darlington, and they one and all have expressed their great surprise at the result, and at the simple and original means by which it is accomplished.

The process is in course of adoption in several works, both in England and abroad, and the author hopes that by the time this paper is being read, there may be some who will from personal experience be able to testify to the practicability and economy of the process, which is carried out in the manner now to be described.

A number of upright pits (the number, say, of the ingots in a cast) are built in a mass of brickwork sunk in the ground below the level of the floor, such pits in cross-section being made slightly larger than that of the ingot, just enough to allow for any fins at the bottom, and somewhat deeper than the longest ingot likely to be used. In practice the cross section of the pit is made about 3 in. larger than the large end of the ingot, and the top of the ingot may be anything from 6 in. to 18 in. below the top of the pit. These pits are commanded by an ingot crane, by preference so placed in relation to the blooming mill that the crane also commands the live rollers of the mill.

Each pit is covered with a separate lid at the floor level, and after having been well dried and brought to a red heat by the insertion of hot ingots, they are ready for operation.

As soon as the ingots are stripped (and they should be stripped as early as practicable), they are transferred one by one, and placed separately by means of the crane into these previously heated pits (which the author calls "soaking pits") and forthwith covered over with the lid, which practically excludes the air. In these pits, thus covered, the ingots are allowed to stand and soak; that is, the excessive molten heat of the interior, and any additional heat rendered sensible during complete solidification, but which was latent at the time of placing the ingots into the pit, becomes uniformly distributed, or nearly so, throughout the metallic mass. No, or comparatively little, heat being able to escape, as the ingot is surrounded by brick walls as hot as itself, it follows that the surface heat of the ingot is greatly increased; and after the space of from twenty to thirty minutes, according to circumstances, the ingot is lifted out of the pit apparently much hotter than it went in, and is now swung round to the rolls, by means of the crane, in a perfect state of heat for rolling, with this additional advantage to the mill over an ingot heated in an ordinary furnace from a comparatively cold, that it is always certain to be at least as hot in the center as it is on the surface.



Every ingot, when cast, contains within itself a considerably larger store of heat than is necessary for the rolling operation. Some of this heat is, of course, lost by passing into the mould, some is lost by radiation before the ingot enters into the soaking pit, and some is lost after it enters, by being conducted away by the brickwork; but in the ordinary course of working, when there is no undue loss of time in transferring the ingots, after allowing for this loss, there remains a surplus, which goes into the brickwork of the soaking pits, so that this surplus of heat from successive ingots tends continually to keep the pits at the intense heat of the ingot itself. Thus, occasionally it happens that inadvertently an ingot is delayed so long on its way to the pit as to arrive there somewhat short of heat, its temperature will be raised by heat from the walls of the pit itself; the refractory mass wherein the pit is formed, in fact, acting as an accumulator of heat, giving and taking heat as required to carry on the operation in a continuous and practical manner.



During the soaking operation a quantity of gas exudes from the ingot and fills the pit, thus entirely excluding atmospheric air from entering; this is seen escaping round the lid, and when the lid is removed combustion takes place.

It will be seen by analyses given hereinafter that this gas is entirely composed of hydrogen, nitrogen, and carbonic oxide, so that the ingots soak in a perfectly non-oxidizing medium. Hence loss of steel by oxidation does not take place, and consequently the great loss of yield which always occurs in the ordinary heating furnace is entirely obviated.

The author does not think it necessary to dilate upon the economical advantages of his process, as they are apparent to every practical man connected with the manufacture of steel.

The operation of steel making on a large scale will by this process be very much simplified. It will help to dispense with a large number of men, some of them highly paid, directly and indirectly connected with the heating department; it will do away with costly heating furnaces and gas generators, and their costly maintenance; it will save all the coal used in heating; and what is perhaps of still more importance, it will save the loss in yield of steel; and there will be no more steel spoiled by overheating in the furnaces.

The process has been in operation too short a time to give precise and reliable figures, but it is hoped that by the next meeting of the Institute these will be forthcoming from various quarters.

Referring to the illustrations annexed, Fig. 1 shows sectional elevation, and Fig. 2 plan of a set of eight soaking pits (marked A). These pits are built in a mass of brickwork, B, on a concrete foundation, C; the ingots, D, standing upright in the pits. The pits are lined with firebrick lumps, 6 in. thick, forming an independent lining, E, which at any time can be readily renewed. F is a cast iron plate, made to take in four pits, and dropped loosely within the large plate, G, which surrounds the pits. H is the cover, with a firebrick lining; and I is a false cover of firebrick, 1 in. smaller than the cross section of the pit, put in to rest on the top of the ingot. This false cover need not necessarily be used, but is useful to keep the extreme top of the ingot extra hot. J is the bottom of the pit, composed of broken brick and silver sand, forming a good hard bottom at any desired level.

Figs. 4 and 5 show outline plan of two sets of soaking pits, K K, eight each, placed under a 25 ft. sweep crane, L. This crane, if a good one, could handle any ordinary make—up to 2,000 tons per week, and ought to have hydraulic racking out and swinging round gear. This crane places the ingots into the pits, and, when they are ready, picks them out and swings them round to blooming mill, M. With such a crane, four men and a boy at the handles are able to pass the whole of that make through the pits. The author recommends two sets of pits as shown, although one set of eight pits is quite able to deal with any ordinary output from one Bessemer pit.

In case of an extraordinarily large output, the author recommends a second crane, F, for the purpose of placing the ingots in the pits only, the crane, L, being entirely used for picking the ingots out and swinging them round to the live rollers of the mill. The relative position of the cranes, soaking pits, and blooming mill may of course be variously arranged according to circumstances, and the soaking pits may be arranged in single or more rows, or concentrically with the crane at pleasure.

Figs. 4 and 5 also show outline plan and elevation of a Bessemer plant, conveniently arranged for working on the soaking pit system. A A are the converters, with a transfer crane, B. C is the casting pit with its crane, D. E E are the two ingot cranes. F is a leading crane which transfers the ingots from the ingot cranes to the soaking pits, K K, commanded by the crane, L, which transfers the prepared ingots to the mill, M. as before described.

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TEMPERING BY COMPRESSION.

L. Clemandot has devised a new method of treating metals, especially steel, which consists in heating to a cherry red, compressing strongly and keeping up the pressure until the metal is completely cooled. The results are so much like those of tempering that he calls his process tempering by compression. The compressed metal becomes exceedingly hard, acquiring a molecular contraction and a fineness of grain such that polishing gives it the appearance of polished nickel. Compressed steel, like tempered steel, acquires the coercitive force which enables it to absorb magnetism. This property should be studied in connection with its durability; experiments have already shown that there is no loss of magnetism at the expiration of three months. This compression has no analogue but tempering. Hammering and hardening modify the molecular state of metals, especially when they are practiced upon metal that is nearly cold, but the effect of hydraulic pressure is much greater. The phenomena which are produced in both methods of tempering may be interpreted in different ways, but it seems likely that there is a molecular approximation, an amorphism from which results the homogeneity that is due to the absence of crystallization. Being an operation which can be measured, it may be graduated and kept within limits which are prescribed in advance; directions may be given to temper at a specified pressure, as readily as to work under a given pressure of steam.—Chron. Industr.

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ECONOMICAL STEAM POWER.

[Footnote: A paper read by title at a recent stated meeting of the Franklin Institute]

By WILLIAM BARNET LE VAN.

The most economical application of steam power can be realized only by a judicious arrangement of the plant: namely, the engines, boilers, and their accessories for transmission.

This may appear a somewhat broad assertion; but it is nevertheless one which is amply justified by facts open to the consideration of all those who choose to seek for them.

While it is true that occasionally a factory, mill, or a water-works may be found in which the whole arrangements have been planned by a competent engineer, yet such is the exception and not the rule, and such examples form but a very small percentage of the whole.

The fact is that but few users of steam power are aware of the numerous items which compose the cost of economical steam power, while a yet smaller number give sufficient consideration to the relations which these items bear to each other, or the manner in which the economy of any given boiler or engine is affected by the circumstances under which it is run.

A large number of persons—and they are those who should know better, too—take for granted that a boiler or engine which is good for one situation is good for all; a greater error than such an assumption can scarcely be imagined.

It is true that there are certain classes of engines and boilers which may be relied upon to give moderately good results in almost any situation—and the best results should always be desired in arrangement of a mill—there are a considerable number of details which must be taken into consideration in making a choice of boilers and engines.

Take the case of a mill in which it has been supposed that the motive power could be best exerted by a single engine. The question now is whether or not it would be best to divide the total power required among a number of engines.

First.—A division of the motive power presents the following advantages, namely, a saving of expense on lines of shafting of large diameter.

Second.—Dispensing with the large driving belt or gearing, the first named of which, in one instance under the writer's observation, absorbed sixty horse-power out of about 480, or about seven per cent.

Third.—The general convenience of subdividing the work to be done, so that in case of a stoppage of one portion of the work by reason of a loose coupling or the changing of a pulley, etc., that portion only would need to be stopped.

This last is of itself a most important point, and demands careful consideration.

For example, I was at a mill a short time ago when the governor belt broke. The result was a stoppage of the whole mill. Had the motive power of this mill been subdivided into a number of small engines only one department would have been stopped. During the stoppage in this case the windows of the mill were a sea of heads of men and women (the operatives), and considerable excitement was caused by the violent blowing off of steam from the safety-valves, due to the stoppage of the steam supply to the engine; and this excitement continued until the cause of the stoppage was understood. Had the power in this mill been subdivided the stoppage of one of a number of engines would scarcely have been noticed, and the blowing off of surplus steam would not have occurred.

In building a mill the first item to be considered is the interest on the first cost of the engine, boilers, etc. This item can be subdivided with advantage into the amounts of interest on the respective costs of,

First. The engine or engines;

Second The boiler or boilers;

Third. The engine and boiler house.

In the same connection the form of engine to be used must be considered. In some few cases—as, for instance, where engines have to be placed in confined situations—the form is practically fixed by the space available, it being perhaps possible only to erect a vertical or a horizontal engine, as the case may be. These, however, are exceptional instances, and in most cases—at all events where large powers are required—the engineer may have a free choice in the matter. Under these circumstances the best form, in the vast majority of cases where machinery must be driven, is undoubtedly the horizontal engine, and the worst the beam engine. When properly constructed, the horizontal engine is more durable than the beam engine, while, its first cost being less, it can be driven at a higher speed, and it involves a much smaller outlay for engine house and foundations than the latter. In many respects the horizontal engine is undoubtedly closely approached in advantages by the best forms of vertical engines; but on the whole we consider that where machinery is to be driven the balance of advantages is decidedly in favor of the former class, and particularly so in the case of large powers.

The next point to be decided is, whether a condensing or non-condensing engine should be employed. In settling this question not only the respective first costs of the two classes of engines must be taken into consideration, but also the cost of water and fuel. Excepting, perhaps, in cases of very small powers, and in those instances where the exhaust steam from a non-condensing engine can be turned to good account for heating or drying purpose, it may safely be asserted that in all instances where a sufficient supply of condensing water is available at a moderate cost, the extra economy of a well-constructed condensing engine will fully warrant the additional outlay involved in its purchase. In these days of high steam pressures, a well constructed non-condensing engine can, no doubt, be made to approximate closely to the economy of a condensing engine, but in such a case the extra cost of the stronger boiler required will go far to balance the additional cost of the condensing engine.

Having decided on the form, the next question is, what "class" of engine shall it be; and by the term class I mean the relative excellence of the engine as a power-producing machine. An automatic engine costs more than a plain slide-valve engine, but it will depend upon the cost of fuel at the location where the engine is to be placed, and the number of hours per day it is kept running, to decide which class of machine can be adopted with the greatest economy to the proprietor. The cost of lubricating materials, fuel, repairs, and percentage of cost to be put aside for depreciation, will be less in case of the high-class than in the low-class engine, while the former will also require less boiler power.

Against these advantages are to be set the greater first cost of the automatic engine, and the consequent annual charge due to capital sunk. These several items should all be fairly estimated when an engine is to be bought, and the kind chosen accordingly. Let us take the item of fuel, for instance, and let us suppose this fuel to cost four dollars per ton at the place where the engine is run. Suppose the engine to be capable of developing one hundred horse-power, and that it consumes five pounds of coal per hour per horse-power, and runs ten hours per day: this would necessitate the supply of two and one-half tons per day at a cost of ten dollars per day. To be really economical, therefore, any improvement which would effect a saving of one pound of coal per hour per horse-power must not cost a greater sum per horse-power than that on which the cost of the difference of the coal saved (one pound of coal per hour per horse-power, which would be 1,000 pounds per day) for, say, three hundred days, three hundred thousand (300,000) pounds, or one hundred and fifty tons (or six hundred dollars), would pay a fair interest.

Assuming that the mill owner estimates his capital as worth to him ten per cent, per annum, then the improvement which would effect the above mentioned saving must not cost more than six thousand dollars, and so on. If, instead of being run only ten hours per day, the engine is run night and day, then the outlay which it would be justifiable to make to effect a certain saving per hour would be doubled; while, on the other hand, if an engine is run less than the usual time per day a given saving per hour would justify a correspondingly less outlay.

It has been found that for grain and other elevators, which are not run constantly, gas engines, although costing more for the same power, are cheaper than steam engines for elevating purposes where only occasionally used.

For this reason it is impossible without considerable investigation to say what is really the most economical engine to adopt in any particular case; and as comparatively few users of steam power care to make this investigation a vast amount of wasteful expenditure results. Although, however, no absolute rule can be given, we may state that the number of instances in which an engine which is wasteful of fuel can be used profitably is exceedingly small. As a rule, in fact, it may generally be assumed that an engine employed for driving a manufactory of any kind cannot be of too high a class, the saving effected by the economical working of such engines in the vast majority of cases enormously outweighing the interest on their extra first cost. So few people appear to have a clear idea of the vast importance of economy of fuel in mills and factories that I perhaps cannot better conclude than by giving an example showing the saving to be effected in a large establishment by an economical engine.

I will take the case of a flouring mill in this city which employed two engines that required forty pounds of water to be converted into steam per hour per indicated horse-power. This, at the time, was considered a moderate amount and the engines were considered "good."

These engines indicated seventy horse power each, and ran twenty-four hours per day on an average of three hundred days each year, requiring as per indicator diagrams forty million three hundred and twenty thousand pounds (40 x 70 x 24 x 300 x 2 = 40,320,000) of feed water to be evaporated per annum, which, in Philadelphia, costs three dollars per horse-power per annum, amounting to (70 x 2 x 300 = $420.00) four hundred and twenty dollars.

The coal consumed averaged five and one-half pounds per hour per horse-power, which, at four dollars per ton, costs

((70 x 2 x 5.5 x 24 x 300) / 2,000) x 4.00= $11,088

Eleven thousand and eighty-eight dollars.

Cost of coal for 300 days. $11,088 Cost of water for 300 days. 420 ———- Total cost of coal and water. $11,503

These engines were replaced by one first-class automatic engine, which developed one hundred and forty-two horse-power per hour with a consumption of three pounds of coal per hour per horse-power, and the indicator diagrams showed a consumption of thirty pounds of water per hour per horse-power. Coal cost

((142 x 3 x 24 x 300) / 2,000) x 4.00 = $6,134

Six thousand one hundred and thirty-four dollars. Water cost (142 x 3.00= $426.00) four hundred and twenty-six dollars.

Cost of coal for 300 days. $6,134 Cost of water for 300 days. 426 ——— Total cost of coal and water. $6,560

The water evaporated in the latter case to perform the same work was (142 x 30 x 24 x 300 = 30,672,000) thirty million six hundred and seventy-two thousand pounds of feed water against (40,320,000) forty million three hundred and twenty thousand pounds in the former, a saving of (9,648,000) nine million six hundred and forty-eight thousand pounds per annum; or,

(40,320,000 - 30,672,000) / 9,648,000 = 31.4 per cent.

thirty-one and four-tenths per cent.

And a saving in coal consumption of

(11,088 - 6,134) / 4,954 = 87.5 per cent.

eighty-seven and one-half per cent., or a saving in dollars and cents of four thousand nine hundred and fifty-four dollars ($4,954).

In this city, Philadelphia, no allowance for the consumption of water is made in the case of first class engines, such engines being charged the same rate per annum per horse-power as an inferior engine, while, as shown by the above example, a saving in water of thirty-one and four-tenths per cent. has been attained by the employment of a first-class engine. The builders of such engines will always give a guarantee of their consumption of water, so that the purchaser can be able in advance to estimate this as accurately as he can the amount of fuel he will use.

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RIVER IMPROVEMENTS NEAR ST. LOUIS.

The improvement of the Mississippi River near St. Louis progresses satisfactorily. The efficacy of the jetty system is illustrated in the lines of mattresses which showed accumulations of sand deposits ranging from the surface of the river to nearly sixteen feet in height. At Twin Hollow, thirteen miles from St. Louis and six miles from Horse-Tail Bar, there was found a sand bar extending over the widest portion of the river on which the engineering forces were engaged. Hurdles are built out from the shore to concentrate the stream on the obstruction, and then to protect the river from widening willows are interwoven between the piles. At Carroll's Island mattresses 125 feet wide have been placed, and the banks revetted with stone from ordinary low water to a 16 foot stage. There is plenty of water over the bar, and at the most shallow points the lead showed a depth of twelve feet. Beard's Island, a short distance further, is also being improved, the largest force of men at any one place being here engaged. Four thousand feet of mattresses have been begun, and in placing them work will be vigorously prosecuted until operations are suspended by floating ice. The different sections are under the direction of W. F. Fries, resident engineer, and E. M. Currie, superintending engineer. There are now employed about 1,200 men, thirty barges and scows, two steam launches, and the stern-wheel steamer A. A. Humphreys. The improvements have cost, in actual money expended, about $200,000, and as the appropriation for the ensuing year approximates $600,000, the prospect of a clear channel is gratifying to those interested in the river.

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BUNTE'S BURETTE FOR THE ANALYSIS OF FURNACE GASES.

For analyzing the gases of blast-furnaces the various apparatus of Orsat have long been employed; but, by reason of its simplicity, the burette devised by Dr. Buente, and shown in the accompanying figures, is much easier to use. Besides, it permits of a much better and more rapid absorption of the oxide of carbon; and yet, for the lost fractions of the latter, it is necessary to replace a part of the absorbing liquid three or four times. The absorbing liquid is prepared by making a saturated solution of chloride of copper in hydrochloric acid, and adding thereto a small quantity of dissolved chloride of tin. Afterward, there are added to the decanted mixture a few spirals of red copper, and the mixture is then carefully kept from contact with the air.

To fill the burette with gas, the three-way cock, a, is so placed that the axial aperture shall be in communication with the graduated part, A, of the burette. After this, water is poured into the funnel, t, and the burette is put in communication with the gas reservoir by means of a rubber tube. The lower point of the burette is put in communication with a rubber pump, V (Fig. 2), on an aspirator (the cock, b, being left open), and the gas is sucked in until all the air that was in the apparatus has been expelled from it. The cocks, a and b, are turned 90 degrees. The water in the funnel prevents the gases communicating with the top. The point of the three-way cock is afterward closed with a rubber tube and glass rod.

If the gas happens to be in the reservoir of an aspirator, it is made to pass into the apparatus in the following manner: The burette is completely filled with water, and the point of the three-way cock is put in communication with a reservoir. If the gas is under pressure, a portion of it is allowed to escape through the capillary tube into the water in the funnel, by turning the cock, a, properly, and thus all the water in the conduit is entirely expelled. Afterward a is turned 180 deg., and the lower cock, b, is opened. While the water is flowing through b, the burette becomes filled with gas.

Mode of Measuring the Gases and Absorption.—The tube that communicates with the vessel, F, is put in communication, after the latter has been completely filled with water, with the point of the cock, b (Fig. 2). Then the latter is opened, as is also the pinch cock on the rubber tubing, and water is allowed to enter the burette through the bottom until the level is at the zero of the graduation. There are then 100 cubic centimeters in the burette. The superfluous gas has escaped through the cock, a, and passed through the water in the funnel. The cock, a, is afterward closed by turning it 90 deg.. To cause the absorbing liquid to pass into the burette, the water in the graduated cylinder is made to flow by connecting the rubber tube, s, of the bottle, S, with the point of the burette. The cock is opened, and suction is effected with the mouth of the tube, r. When the water has flowed out to nearly the last drop, b is closed and the suction bottle is removed. The absorbing liquid (caustic potassa or pyrogallate of potassa) is poured into a porcelain capsule, P, and the point of the burette is dipped into the liquid. If the cock, b, be opened, the absorbing liquid will be sucked into the burette. In order to hasten the absorption, the cock, b, is closed, and the burette is shaken horizontally, the aperture of the funnel being closed by the hand during the operation.

If not enough absorbing liquid has entered, there may be sucked into the burette, by the process described above, a new quantity of liquid. The reaction finished, the graduated cylinder is put in communication with the funnel by turning the cock, a. The water is allowed to run from the funnel, and the latter is filled again with water up to the mark. The gas is then again under the same pressure as at the beginning.

After the level has become constant, the quantity of gas remaining is measured. The contraction that has taken place gives, in hundredths of the total volume, the volume of the gas absorbed.

When it is desired to make an analysis of smoke due to combustion, caustic potassa is first sucked into the burette. After complete absorption, and after putting the gas at the same pressure, the diminution gives the volume of carbonic acid.

To determine the oxygen in the remaining gas, a portion of the caustic potash is allowed to flow out, and an aqueous solution of pyrogallic acid and potash is allowed to enter. The presence of oxygen is revealed by the color of the liquid, which becomes darker.

The gas is then agitated with the absorbing liquid until, upon opening the cock, a, the liquid remains in the capillary tube, that is to say, until no more water runs from the funnel into the burette. To make a quantitative analysis of the carbon contained in gas, the pyrogallate of potash must be entirely removed from the burette. To do this, the liquid is sucked out by means of the flask, S, until there remain only a few drops; then the cock, a, is opened and water is allowed to flow from the funnel along the sides of the burette. Then a is closed, and the washing water is sucked in the same manner. By repeating this manipulation several times, the absorbing liquid is completely removed. The acid solution of chloride of copper is then allowed to enter.

As the absorbing liquids adhere to the glass, it is better, before noting the level, to replace these liquids by water. The cocks, a and b, are opened, and water is allowed to enter from the funnel, the absorbing liquid being made to flow at the same time through the cock, b.

When an acid solution of chloride of copper is employed, dilute hydrochloric acid is used instead of water.

Fig. 2 shows the arrangement of the apparatus for the quantitative analysis of oxide of carbon and hydrogen by combustion. The gas in the burette is first mixed with atmospheric air, by allowing the liquid to flow through b, and causing air to enter through the axial aperture of the three way cock, a, after cutting off communication at v. Then, as shown in the figure, the burette is connected with the tube, B, which is filled with water up to the narrow curved part, and the interior of the burette is made to communicate with the combustion tube, v, by turning the cock, a. The combustion tube is heated by means of a Bunsen burner or alcohol lamp, L. It is necessary to proceed, so that all the water shall be driven from the cock and the capillary tube, and that it shall be sent into the burette. The combustion is effected by causing the mixture of gas to pass from the burette into the tube, B, through the tube, v, heated to redness, into which there passes a palladium wire. Water is allowed to flow through the point of the tube, B, while from the flask, F, it enters through the bottom into the burette, so as to drive out the gas. The water is allowed to rise into the burette as far as the cock, and the cocks, b and b, are afterward closed.



By a contrary operation, the gas is made to pass from B into the burette. It is then allowed to cool, and, after the pressure has been established again, the contraction is measured. If the gas burned is hydrogen, the contraction multiplied by two-thirds gives the original volume of the hydrogen gas burned. If the gas burned is oxide of carbon, there forms an equal volume of carbonic acid, and the contraction is the half of CO. Thus, to analyze CO, a portion of the liquid is removed from the burette, then caustic potash is allowed to enter, and the process goes on as explained above.

The total contraction resulting from combustion and absorption, multiplied by two-thirds, gives the volume of the oxide of carbon.

The hydrogen and oxide carbon may thus be quantitatively analyzed together or separately.—Revue Industrielle.

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THE "UNIVERSAL" GAS ENGINE.

The accompanying engravings illustrate a new and very simple form of gas engine, the invention of J. A. Ewins and H. Newman, and made by Mr. T. B. Barker, of Scholefield-street, Bloomsbury, Birmingham. It is known as the "Universal" engine, and is at present constructed in sizes varying from one-eighth horse-power—one man power—to one horse-power, though larger sizes are being made. The essentially new feature of the engine is, says the Engineer, the simple rotary ignition valve consisting of a ratchet plate or flat disk with a number of small radial slots which successively pass a small slot in the end of the cylinder, and through which the flame is drawn to ignite the charge. In our illustrations Fig. 1 is a side elevation; Fig. 2 an end view of same; Fig. 3 a plan; Fig. 4 is a sectional view of the chamber in which the gas and air are mixed, with the valves appertaining thereto; Fig. 5 is a detail view of the ratchet plate, with pawl and levers and valve gear shaft; Fig. 6 is a sectional view of a pump employed in some cases to circulate water through the jacket; Fig. 7 is a sectional view of arrangement for lighting, and ratchet plate, j, with central spindle and igniting apertures, and the spiral spring, k, and fly nut, showing the attachment to the end of the working cylinder, f1; b5, b5, bevel wheels driving the valve gear shaft; e, the valve gear driving shaft; e2, eccentric to drive pump; e cubed, eccentric or cam to drive exhaust valve; e4, crank to drive ratchet plate; e5, connecting rod to ratchet pawl; f, cylinder jacket; f1, internal or working cylinder; f2, back cylinder cover; g, igniting chamber; h, mixing chamber; h1, flap valve; h2, gas inlet valve, the motion of which is regulated by a governor; h3, gas inlet valve seat; h4, cover, also forming stop for gas inlet valve; h5, gas inlet pipe; h6, an inlet valve; h8, cover, also forming stop for air inlet valve; h9, inlet pipe for air with grating; i, exhaust chamber; i2, exhaust valve spindle; i7, exhaust pipe; j6, lighting aperture through cylinder end; l, igniting gas jet; m, regulating and stop valve for gas.



The engine, it will be seen, is single-acting, and no compression of the explosive charge is employed. An explosive mixture of combustible gas and air is drawn through the valves, h2 and h6, and exploded behind the piston once in a revolution; but by a duplication of the valve and igniting apparatus, placed also at the front end of the cylinder, the engine may be constructed double-acting. At the proper time, when the piston has proceeded far enough to draw in through the mixing chamber, h, into the igniting chamber, g, the requisite amount of gas and air, the ratchet plate, j, is pushed into such a position by the pawl, j3, that the flame from the igniting jet, l, passes through one of the slots or holes, j1, and explodes the charge when opposite j6, which is the only aperture in the end of the working cylinder (see Fig. 7 and Fig. 2), thus driving the piston on to the end of its forward stroke. The exhaust valve, Fig. 9, though not exactly of the form shown, is kept open during the whole of this return stroke by means of the eccentric, e3, on the shaft working the ratchet, and thus allowing the products of combustion to escape through the exhaust pipe, i7, in the direction of the arrow. Between the ratchet disk and the igniting flame a small plate not shown is affixed to the pipe, its edge being just above the burner top. The flame is thus not blown out by the inrushing air when the slots in ratchet plate and valve face are opposite. This ratchet plate or ignition valve, the most important in any engine, has so very small a range of motion per revolution of the engine that it cannot get out of order, and it appears to require no lubrication or attention whatever. The engines are working very successfully, and their simplicity enables them to be made at low cost. They cost for gas from 1/2d. to 11/2d. per hour for the sizes mentioned.



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GAS FURNACE FOR BAKING REFRACTORY PRODUCTS.

In order that small establishments may put to profit the advantages derived from the use of annular furnaces heated with gas, smaller dimensions have been given the baking chambers of such furnaces. The accompanying figure gives a section of a furnace of this kind, set into the ground, and the height of whose baking chamber is only one and a half meters. The chamber is not vaulted, but is covered by slabs of refractory clay, D, that may be displaced by the aid of a small car running on a movable track. This car is drawn over the compartment that is to be emptied, and the slab or cover, D, is taken off and carried over the newly filled compartment and deposited thereon.

The gas passes from the channel through the pipe, a, into the vertical conduits, b, and is afterward disengaged through the tuyeres into the chamber. In order that the gas may be equally applied for preliminary heating or smoking, a small smoking furnace, S, has been added to the apparatus. The upper part of this consists of a wide cylinder of refractory clay, in the center of whose cover there is placed an internal tube of refractory clay, which communicates with the channel, G, through a pipe, d. This latter leads the gas into the tube, t, of the smoking furnace, which is perforated with a large number of small holes. The air requisite for combustion enters through the apertures, o, in the cover of the furnace, and brings about in the latter a high temperature. The very hot gases descend into the lower iron portion of this small furnace and pass through a tube, e, into the smoking chamber by the aid of vertical conduits, b', which serve at the same time as gas tuyeres for the extremity of the furnace that is exposed to the fire.



In the lower part of the smoking furnace, which is made of boiler plate and can be put in communication with the tube, e, there are large apertures that may be wholly or partially closed by means of registers so as to carry to the hot gas derived from combustion any quantity whatever of cold and dry air, and thus cause a variation at will of the temperature of the gases which are disengaged from the tube, e.

The use of these smoking apparatus heated by gas does away also with the inconveniences of the ordinary system, in which the products are soiled by cinders or dust, and which render the gradual heating of objects to be baked difficult. At the beginning, there is allowed to enter the lower part of the small furnace, S, through the apertures, a very considerable quantity of cold air, so as to lower the temperature of the smoke gas that escapes from the tube, e, to 30 or 50 degrees. Afterward, these secondary air entrances are gradually closed so as to increase the temperature of the gases at will.

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THE EFFICIENCY OF FANS.

Air, like every other gas or combination of gases, possesses weight; some persons who have been taught that the air exerts a pressure of 14.7 lb. per square inch, cannot, however, be got to realize the fact that a cubit foot of air at the same pressure and at a temperature of 62 deg. weighs the thirteenth part of a pound, or over one ounce; 13.141 cubic feet of air weigh one pound. In round numbers 30,000 cubic feet of air weigh one ton; this is a useful figure to remember, and it is easily carried in the mind. A hall 61 feet long, 30 feet wide, and 17 feet high will contain one ton of air.



The work to be done by a fan consists in putting a weight—that of the air—in motion. The resistances incurred are due to the inertia of the air and various frictional influences; the nature and amount of these last vary with the construction of the fan. As the air enters at the center of the fan and escapes at the circumference, it will be seen that its motion is changed while in the fan through a right angle. It may also be taken for granted that within certain limits the air has no motion in a radial direction when it first comes in contact with a fan blade. It is well understood that, unless power is to be wasted, motion should be gradually imparted to any body to be moved. Consequently, the shape of the blades ought to be such as will impart motion at first slowly and afterward in a rapidly increasing ratio to the air. It is also clear that the change of motion should be effected as gradually as possible. Fig. 1 shows how a fan should not be constructed; Fig. 2 will serve to give an idea of how it should be made.



In Fig. 1 it will be seen that the air, as indicated by the bent arrows, is violently deflected on entering the fan. In Fig. 2 it will be seen that it follows gentle curves, and so is put gradually in motion. The curved form of the blades shown in Fig. 2 does not appear to add much to the efficiency of a fan; but it adds something and keeps down noise. The idea is that the fan blades when of this form push the air radially from the center to the circumference. The fact is, however, that the air flies outward under the influence of centrifugal force, and always tends to move at a tangent to the fan blades, as in Fig. 3, where the circle is the path of the tips of the fan blades, and the arrow is a tangent to that path; and to impart this notion a radial blade, as at C, is perhaps as good as any other, as far as efficiency is concerned. Concerning the shape to be imparted to the blades, looked at back or front, opinions widely differ; but it is certain that if a fan is to be silent the blades must be narrower at the tips than at the center. Various forms are adopted by different makers, the straight side and the curved sides, as shown in Fig. 4, being most commonly used. The proportions as regards length to breadth are also varied continually. In fact, no two makers of fans use the same shapes.



As the work done by a fan consists in imparting motion at a stated velocity to a given weight of air, it is very easy to calculate the power which must be expended to do a certain amount of work. The velocity at which the air leaves the fan cannot be greater than that of the fan tips. In a good fan it may be about two-thirds of that speed. The resistance to be overcome will be found by multiplying the area of the fan blades by the pressure of the air and by the velocity of the center of effort, which must be determined for every fan according to the shape of its blades. The velocity imparted to the air by the fan will be just the same as though the air fell in a mass from a given height. This height can be found by the formula h = v squared / 64; that is to say, if the velocity be multiplied by itself and divided by 64 we have the height. Thus, let the velocity be 88 per second, then 88 x 88 = 7,744, and 7,744 / 64 = 121. A stone or other body falling from a height of 121 feet would have a velocity of 88 per second at the earth. The pressure against the fan blades will be equal to that of a column of air of the height due to the velocity, or, in this case, 121 feet. We have seen that in round numbers 13 cubic feet of air weigh one pound, consequently a column of air one square foot in section and 121 feet high, will weigh as many pounds as 13 will go times into 121. Now, 121 / 13 = 9.3, and this will be the resistance in pounds per square foot overcome by the fan. Let the aggregate area of all the blades be 2 square feet, and the velocity of the center of effort 90 feet per second, then the power expended will bve (90 x 60 x 2 x 9.3) / 33,000 = 3.04 horse power. The quantity of air delivered ought to be equal in volume to that of a column with a sectional area equal that of one fan blade moving at 88 feet per second, or a mile a minute. The blade having an area of 1 square foot, the delivery ought to be 5,280 feet per minute, weighing 5,280 / 13 = 406.1 lb. In practice we need hardly say that such an efficiency is never attained.



The number of recorded experiments with fans is very small, and a great deal of ignorance exists as to their true efficiency. Mr. Buckle is one of the very few authorities on the subject. He gives the accompanying table of proportions as the best for pressures of from 3 to 6 ounces per square inch:

Vanes. Diameter of inlet Diameter of fans. openings. Width. Length. ft. in. ft. in. ft. in. ft. in. 3 0 0 9 0 9 1 6 3 6 0 101/2 0 101/2 1 9 4 0 1 0 1 0 2 0 4 6 1 11/2 1 11/2 2 3 5 0 1 3 1 3 2 6 6 0 1 6 1 6 3 0

For higher pressures the blades should be longer and narrower, and the inlet openings smaller. The case is to be made in the form of an arithmetical spiral widening, the space between the case and the blades radially from the origin to the opening for discharge, and the upper edge of the opening should be level with the lower side of the sweep of the fan blade, somewhat as shown in Fig. 5.



A considerable number of patents has been taken out for improvements in the construction of fans, but they all, or nearly all, relate to modifications in the form of the case and of the blades. So far, however, as is known, it appears that, while these things do exert a marked influence on the noise made by a fan, and modify in some degree the efficiency of the machine, that this last depends very much more on the proportions adopted than on the shapes—so long as easy curves are used and sharp angles avoided. In the case of fans running at low speeds, it matters very little whether the curves are present or not; but at high speeds the case is different.—The Engineer.

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MACHINE FOR COMPRESSING COAL REFUSE INTO FUEL.

The problem as to how the refuse of coal shall be utilized has been solved in the manufacture from it of an agglomerated artificial fuel, which is coming more and more into general use on railways and steamboats, in the industries, and even in domestic heating.

The qualities that a good agglomerating machine should present are as follows:

1. Very great simplicity, inasmuch as it is called upon to operate in an atmosphere charged with coal dust, pitch, and steam; and, under such conditions, it is important that it may be easily got at for cleaning, and that the changing of its parts (which wear rapidly) may be effected without, so to speak, interrupting its running.

2. The compression must be powerful, and, that the product may be homogeneous, must operate progressively and not by shocks. It must especially act as much as possible upon the entire surface of the conglomerate, and this is something that most machines fail to do.

3. The removal from the mould must be effected easily, and not depend upon a play of pistons or springs, which soon become foul, and the operation of which is very irregular.

The operations embraced in the manufacture of this kind of fuel are as follows:

The refuse is sifted in order to separate the dust from the grains of coal. The dust is not submitted to a washing. The grains are classed into two sizes, after removing the nut size, which is sold separately. The grains of each size are washed separately. The washed grains are either drained or dried by a hydro-extractor in order to free them from the greater part of the water, the presence of this being an obstacle to their perfect agglomeration. The water, however, should not be entirely extracted because the combustibles being poor conductors of heat, a certain amount of dampness must be preserved to obtain an equal division of heat in the paste when the mixture is warmed.

After being dried the grains are mixed with the coal dust, and broken coal pitch is added in the proportion of eight to ten per cent. of the coal. The mixture is then thrown into a crushing machine, where it is reduced to powder and intimately mixed. It then passes into a pug-mill into which superheated steam is admitted, and by this means is converted into a plastic paste. This paste is then led into an agitator for the double purpose of freeing it from the steam that it contains, and of distributing it in the moulds of the compressing machine.



Bilan's machine, shown in the accompanying cut, is designed for manufacturing spherical conglomerates for domestic purposes. It consists of a cast iron frame supporting four vertical moulding wheels placed at right angles to each other and tangent to the line of the centers. These wheels carry on their periphery cavities that have the form of a quarter of a sphere. They thus form at the point of contact a complete sphere in which the material is inclosed. The paste is thrown by shovel, or emptied by buckets and chain, into the hopper fixed at the upper part of the frame. From here it is taken up by two helices, mounted on a vertical shaft traversing the hopper, and forced toward the point where the four moulding wheels meet. The driving pulley of the machine is keyed upon a horizontal shaft which is provided with two endless screws that actuate two gear-wheels, and these latter set in motion the four moulding wheels by means of beveled pinions. The four moulding wheels being accurately adjusted so that their cavities meet each other at every revolution, carry along the paste furnished them by the hopper, compress it powerfully on the four quarters, and, separating by a further revolution, allow the finished ball to drop out.

The external crown of the wheels carrying the moulds consists of four segments, which may be taken apart at will to be replaced by others when worn.

This machine produces about 40 tons per day of this globular artificial fuel.—Annales Industrielles.

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HANK SIZING AND WRINGING MACHINE.

We give a view of a hank sizing machine by Messrs. Heywood & Spencer, of Radcliffe, near Manchester. The machine is also suitable for fancy dyeing. It is well known, says the Textile Manufacturer, that when hanks are wrung by hand, not only is the labor very severe, but in dyeing it is scarcely possible to obtain even colors, and, furthermore, the production is limited by the capabilities of the man. The machine we illustrate is intended to perform the heavy part of the work with greater expedition and with more certainty than could be relied upon with hand labor. The illustration represents the machine that we inspected. Its construction seems of the simplest character. It consists of two vats, between which is placed the gearing for driving the hooks. The large wheel in this gear, although it always runs in one direction, contains internal segments, which fall into gear alternately with pinions on the shanks of the hooks. The motion is a simple one, and it appeared to us to be perfectly reliable, and not liable to get out of order. The action is as follows: The attendant lifts the hank out of the vat and places it on the hooks. The hook connected to the gearing then commences to turn; it puts in two, two and a half, three, or more twists into the hank and remains stationary for a few seconds to allow an interval for the sizer to "wipe off" the excess of size, that is, to run his hand along the twisted hank. This done, the hook commences to revolve the reverse way, until the twists are taken out of the hank. It is then removed, either by lifting off by hand or by the apparatus shown, attached to the right hand side. This arrangement consists of a lattice, carrying two arms that, at the proper moment, lift the hank off the hooks on to the lattice proper, by which it is carried away, and dropped upon a barrow to be taken to the drying stove. In sizing, a double operation is customary; the first is called running, and the second, finishing. In the machine shown, running is carried on one side simultaneously with finishing in the other, or, if required, running may be carried on on both sides. If desired, the lifting off motion is attached to both running and finishing sides, and also the roller partly seen on the left hand for running the hanks through the size. The machine we saw was doing about 600 bundles per day at running and at finishing, but the makers claim the production with a double machine to be at the rate of about 36 10 lb. bundles per hour (at finishing), wrung in 11/2 lb. wringers (or I1/2 lb. of yarn at a time), or at running at the rate of 45 bundles in 2 lb. wringers. The distance between the hooks is easily adjusted to the length or size of hanks, and altogether the machine seems one that is worth the attention of the trade.



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IMPROVED COKE BREAKER.

The working parts of the breaker now in use by the South Metropolitan Gas Company consist essentially of a drum provided with cutting edges projecting from it, which break up the coke against a fixed grid. The drum is cast in rings, to facilitate repairs when necessary, and the capacity of the machine can therefore be increased or diminished by varying the number of these rings. The degree of fineness of the coke when broken is determined by the regulated distance of the grid from the drum. Thus there is only one revolving member, no toothed gearing being required. Consequently the machine works with little power; the one at the Old Kent Road, which is of the full size for large works, being actually driven by a one horse power "Otto" gas-engine. Under these conditions, at a recent trial, two tons of coke were broken in half an hour, and the material delivered screened into the three classes of coke, clean breeze (worth as much as the larger coke), and dust, which at these works is used to mix with lime in the purifiers. The special advantage of the machine, besides the low power required to drive it and its simple action, lies in the small quantity of waste. On the occasion of the trial in question, the dust obtained from two tons of coke measured only 31/2 bushels, or just over a half hundredweight per ton. The following statement, prepared from the actual working of the first machine constructed, shows the practical results of its use. It should be premised that the machine is assumed to be regularly employed and driven by the full power for which it is designed, when it will easily break 8 tons of coke per hour, or 80 tons per working day:

500 feet of gas consumed by a 2 horse power gas-engine, at cost price of gas delivered s. d. in holder. 0 9 Oil and cotton waste. 0 6 Two men supplying machine with large coke, and shoveling up broken, at 4s. 6d. 9 0 Interest and wear and tear (say). 0 3 ——- Total per day. 10 6 ——- For 80 tons per day, broken at the rate of. 0 11/2 Add for loss by dust and waste, 1 cwt., with price of coke at (say) 13s. 4d. per ton. 0 8 ——- Cost of breaking, per ton. 0 91/2

As coke, when broken, will usually fetch from 2s. to 2s. 6d. per ton more than large, the result of using these machines is a net gain of from 1s. 3d. to 1s. 9d. per ton of coke. It is not so much the actual gain, however, that operates in favor of providing a supply of broken coke, as the certainty that by so doing a market is obtained that would not otherwise be available.



It will not be overstating the case to say that this coke breaker is by far the simplest, strongest, and most economical appliance of its kind now manufactured. That it does its work well is proved by experience; and the advantages of its construction are immediately apparent upon comparison of its simple drum and single spindle with the flying hammers or rocking jaws, or double drums with toothed gearing which characterize some other patterns of the same class of plant. It should be remarked, as already indicated, lest exception should be taken to the size of the machine chosen here for illustration, that it can be made of any size down to hand power. On the whole, however, as a few tons of broken coke might be required at short notice even in a moderate sized works, it would scarcely be advisable to depend upon too small a machine; since the regular supply of the fuel thus improved may be trusted in a short time to increase the demand.



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IMPROVEMENT IN PRINTING MACHINERY.

This is the design of Alfred Godfrey, of Clapton. According to this improvement, as represented at Figs. 1 and 2, a rack, A, is employed vibrating on the pivot a, and a pinion, a1, so arranged that instead of the pinion moving on a universal joint, or the rack moving in a parallel line from side to side of the pinion at the time the motion of the table is reversed, there is employed, for example, the radial arm, a2, mounted on the shaft, a3, supporting the driving wheel, a4. The opposite or vibrating end of the radial arm, a2, supports in suitable bearings the pinion, a1, and wheel, a5, driving the rack through the medium of the driving wheel, a4, the effect of which is that through the mechanical action of the vibrating arm, a2, and pinion, a1 in conjunction with the vibrating movement of the rack, A, an easy, uniform, and silent motion is transmitted to the rack and table.



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A CHARACTERISTIC MINING "RUSH."—THE PROSPECTIVE MINING CENTER OF SOUTHERN NEW MEXICO.

A correspondent of the Tribune describes at length the mining camps about Lake Valley, New Mexico, hitherto thought likely to be the central camp of that region, and then graphically tells the story of the recent "rush" to the Perche district. Within a month of the first strike of silver ore the country was swarming with prospectors, and a thousand or more prospects had been located.

The Perche district is on the eastern flanks of the Mimbres Mountains, a range which is a part of the Rocky Mountain range, and runs north and south generally parallel with the Rio Grande, from which it lies about forty miles to the westward. The northern half of these mountains is known as the Black Range, and was the center of considerable mining excitement a year and a half ago. It is there that the Ivanhoe is located, of which Colonel Gillette was manager, and in which Robert Ingersoll and Senator Plumb, of Kansas, were interested, much to the disadvantage of the former. A new company has been organized, however, with Colonel Ingersoll as president, and the reopening of work on the Ivanhoe will probably prove a stimulus to the whole Black Range. From this region the Perche district is from forty to sixty miles south. It is about twenty-five miles northwest of Lake Valley, and ten miles west of Hillsboro, a promising little mining town, with some mills and about 300 people. The Perche River has three forks coming down from the mountains and uniting at Hillsboro, and it is in the region between these forks that the recent strikes have been made.

On August 15 "Jack" Shedd, the original discoverer of the Robinson mine in Colorado, was prospecting on the south branch of the north fork of the Perche River, when he made the first great strike in the district. On the summit of a heavily timbered ridge he found some small pieces of native silver, and then a lump of ore containing very pure silver in the form of sulphides, weighing 150 pounds, and afterward proved to be worth on the average $11 a pound. All this was mere float, simply lying on the surface of the ground. Afterward another block was found, weighing 87 pounds, of horn silver, with specimens nearly 75 per cent. silver. The strike was kept a secret for a few days. Said a mining man: "I went up to help bring the big lump down. We took it by a camp of prospectors who were lying about entirely ignorant of any find. When they saw it they instantly saddled their horses, galloped off, and I believe they prospected all night." A like excitement was created when the news of this and one or two similar finds reached Lake Valley. Next morning every waiter was gone from the little hotel, and a dozen men had left the Sierra mines, to try their fortunes at prospecting.

As the news spread men poured into the Perche district from no one knows where, some armed with only a piece of salt pork, a little meal, and a prospecting pick; some mounted on mules, others on foot; old men and men half-crippled were among the number, but all bitten by the monomania which possesses every prospector. Now there are probably 2,000 men in the Perche district, and the number of prospects located must far exceed 1,000. Three miners from there with whom I was talking recently owned forty-seven mines among them, and while one acknowledged that hardly one prospect in a hundred turns out a prize, the other millionaire in embryo remarked that he wouldn't take $50,000 for one of his mines. So it goes, and the victims of the mining fever here seem as deaf to reason as the buyers of mining stock in New York. Fuel was added to the flame by the report that Shedd had sold his location, named the Solitaire, to ex-Governor Tabor and Mr. Wurtzbach on August 25 for $100,000. This was not true. I met Governor Tabor's representative, who came down recently to examine the properties, and learned that the Governor had not up to that date bought the mine. He undoubtedly bonded it, however, and his representative's opinion of the properties seemed highly favorable. The Solitaire showed what appeared to be a contact vein, with walls of porphyry and limestone in a ledge thirty feet wide in places, containing a high assay of horned silver. The vein was composed of quartz, bearing sulphides, with horn silver plainly visible, giving an average assay of from $350 to $500. This was free milling. These were the results shown simply by surface explorations, which were certainly exceedingly promising. Recently it has been stated that a little development shows the vein to be only a blind lead, but the statement lacks confirmation. In any case the effect of so sensational a discovery is the same in creating an intense excitement and attracting swarms of prospectors.

But the Perche district does not rest on the Solitaire, for there has been abundance of mineral wealth discovered throughout its extent. Four miles south of this prospect, on the middle fork of the Perche, is an actual mine—the Bullion—which was purchased by four or five Western mining men for $10,000, and yielded $11,000 in twenty days. The ore contains horn and native silver. On the same fork are the Iron King and Andy Johnson, both recently discovered and promising properties, and there is a valuable mine now in litigation on the south fork of the Perche, with scores of prospects over the entire district. Now that one or two sensational strikes have attracted attention, and capital is developing paying mines, the future of the Perche District seems assured.

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THE SOY BEAN.

The British Medical Journal says that Prof. E. Kinch, writing in the Agricultural Students' Gazette, says that the Soy bean approaches more nearly to animal food than any other known vegetable production, being singularly rich in fat and in albuminoids. It is largely used as an article of food in China and Japan. Efforts have been made to acclimatize it in various parts of the continent of Europe, and fair success has been achieved in Italy and France; many foods are made from it and its straw is a useful fodder.

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ON A NEW ARC ELECTRIC LAMP.

[Footnote: Paper read at the British Association, Southampton. Revised by the Author.—Nature.]

By W.H. PREECE.

Electric lamps on the arc principle are almost as numerous as the trees in the forest, and it is somewhat fresh to come upon something that is novel. In these lamps the carbons are consumed as the current flows, and it is the variation in their consumption which occasions the flickering and irregularity of the light that is so irritating to the eyes. Special mechanical contrivances or regulators have to be used to compensate for this destruction of the carbons, as in the Siemens and Brush type, or else refractory materials have to be combined with the carbons, as in the Jablochkoff candle and in the lamp Soleil. The steadiness of the light depends upon the regularity with which the carbons are moved toward each other as they are consumed, so as to maintain the electric resistance between them a constant quantity. Each lamp must have a certain elasticity of regulation of its own, to prevent irregularities from the variable material of carbon used, and from variations in the current itself and in the machinery.

In all electric lamps, except the Brockie, the regulator is in the lamp itself. In the Brockie system the regulation is automatic, and is made at certain rapid intervals by the motor engine. This causes a periodic blinking that is detrimental to this lamp for internal illumination.



M. Abdank, the inventor of the system which I have the pleasure of bringing before the Section, separates his regulator from his lamp. The regulator may be fixed anywhere, within easy inspection and manipulation, and away from any disturbing influence in the lamp. The lamp can be fixed in any inaccessible place.

The Lamp (Figs. 1, 2, and 3.)—The bottom or negative carbon is fixed, but the top or positive carbon is movable, in a vertical line. It is screwed at the point, C, to a brass rod, T (Fig. 2), which moves freely inside the tubular iron core of an electromagnet, K. This rod is clutched and lifted by the soft iron armature, A B, when a current passes through the coil, M M. The mass of the iron in the armature is distributed so that the greater portion is at one end, B, much nearer the pole than the other end. Hence this portion is attracted first, the armature assumes an inclined position, maintained by a brass button, t, which prevents any adhesion between the armature and the core of the electromagnet. The electric connection between the carbon and the coil of the electromagnet is maintained by the flexible wire, S.



The electromagnet, A (Fig. 1), is fixed to a long and heavy rack, C, which falls by its own weight and by the weight of the electromagnet and the carbon fixed to it. The length of the rack is equal to the length of the two carbons. The fall of the rack is controlled by a friction break, B (Fig. 3), which acts upon the last of a train of three wheels put in motion by the above weight. The break, B, is fixed at one end of a lever, B A, the other end carrying a soft iron armature, F, easily adjusted by three screws. This armature is attracted by the electromagnet, E E (whose resistance is 1,200 ohms), whenever a current circulates through it. The length of the play is regulated by the screw, V. The spring, L, applies tension to the break.

The Regulator.—This consists of a balance and a cut-off.

The Balance (Figs. 4 and 5) is made with two solenoids. S and S', whose relative resistances is adjustable. S conveys the main current, and is wound with thick wire having practically no resistance, and S' is traversed by a shunt current, and is wound with fine wire having a resistance of 600 ohms. In the axes of these two coils a small and light iron tube (2 mm. diameter and 60 mm. length) freely moves in a vertical line between two guides. When magnetized it has one pole in the middle and the other at each end. The upward motion is controlled by the spring, N T. The spring rests upon the screw, H, with which it makes contact by platinum electrodes. This contact is broken whenever the little iron rod strikes the spring, N T.

The positive lead from the dynamo is attached to the terminal, B, then passes through the coil, S, to the terminal, B', whence it proceeds to the lamp. The negative lead is attached to terminal, A, passing directly to the other terminal, A', and thence to the lamp.



The shunt which passes through the fine coil, S', commences at the point, P. The other end is fixed to the screw, H, whence it has two paths, the one offering no resistance through the spring, T N, to the upper negative terminal, A'; the other through the terminal, J, to the electromagnet of the break, M, and thence to the negative terminal of the lamp, L'.



The Cut-off.—The last part of the apparatus (Fig. 4) to be described is the cut-off, which is used when there are several lamps in series. It is brought into play by the switch, C D, which can be placed at E or D. When it is at E, the negative terminal, A, is in communication with the positive terminal, B, through the resistance, R, which equals the resistance of the lamp, which is, therefore, out of circuit. When it is at D the cut-off acts automatically to do the same thing when required. This is done by a solenoid, V, which has two coils, the one of thick wire offering no resistance, and the other of 2,000 ohms resistance. The fine wire connects the terminals, A' and B. The solenoid has a movable soft iron core suspended by the spring, U. It has a cross-piece of iron which can dip into two mercury cups, G and K, when the core is sucked into the solenoid. When this is the case, which happens when any accident occurs to the lamp, the terminal, A, is placed in connection with the terminal, B, through the thick wire of V and the resistance, R, in the same way as it was done by the switch, C D.

Electrical Arrangement.—The mode in which several lamps are connected up in series is shown by Fig. 6. M is the dynamo machine. The + lead is connected to B1 of the balance it then passes to the lamp, L, returning to the balance, and then proceeds to each other lamp, returning finally to the negative pole of the machine. When the current enters the balance it passes through the coil, S, magnetizing the iron core and drawing it downward (Fig. 4). It then passes to the lamp, L L', through the carbons, then returns to the balance, and proceeds back to the negative terminal of the machine. A small portion of the current is shunted off at the point, P, passing through the coil, S', through the contact spring, T N, to the terminal, A', and drawing the iron core in opposition to S. The carbons are in contact, but in passing through the lamp the current magnetizes the electromagnet, M (Fig. 2), which attracts the armature, A B, that bites and lifts up the rod, T, with the upper carbon, a definite and fixed distance that is easily regulated by the screws, Y Y. The arc then is formed, and will continue to burn steadily as long as the current remains constant. But the moment the current falls, due to the increased resistance of the arc, a greater proportion passes through the shunt, S' (Fig. 4), increasing its magnetic moment on the iron core, while that of S is diminishing. The result is that a moment arrives when equilibrium is destroyed, the iron rod strikes smartly and sharply upon the spring, N T. Contact between T and H is broken, and the current passes through the electromagnet of the break in the lamp. The break is released for an instant, the carbons approach each other. But the same rupture of contact introduces in the shunt a new resistance of considerable magnitude (viz., 1,200 ohms), that of the electromagnets of the break. Then the strength of the shunt current diminishes considerably, and the solenoid, S, recovers briskly its drawing power upon the rod, and contact is restored. The carbons approach during these periods only about 0.01 to 0.02 millimeter. If this is not sufficient to restore equilibrium it is repeated continually, until equilibrium is obtained. The result is that the carbon is continually falling by a motion invisible to the eye, but sufficient to provide for the consumption of the carbons.



The contact between N T and H is never completely broken, the sparks are very feeble, and the contacts do not oxidize. The resistances inserted are so considerable that heating cannot occur, while the portion of the current abstracted for the control is so small that it may be neglected.

The balance acts precisely like the key of a Morse machine, and the break precisely like the sounder-receiver so well known in telegraphy. It emits the same kind of sounds, and acts automatically like a skilled and faithful telegraphist.

This regulation, by very small and short successive steps, offers several advantages: (1) it is imperceptible to the eye; (2) it does not affect the main current; (3) any sudden instantaneous variation of the main current does not allow a too near approach of the carbon points. Let, now, an accident occur; for instance, a carbon is broken. At once the automatic cut-off acts, the current passes through the resistance, R, instead of passing through the lamp. The current through the fine coil is suddenly increased, the rod is drawn in, contact is made at G and K, and the current is sent through the coil, R. As soon as contact is again made by the carbons, the current in the coil, S, is increased, that of the thick wire in V diminished, and the antagonistic spring, U, breaks the contact at G and K. The rupture of the light is almost invisible, because the relighting is so brisk and sharp.

I have seen this lamp in action, and its constant steadiness leaves nothing to be desired.

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APPARATUS FOR OBTAINING PURE WATER FOR PHOTOGRAPHIC USE.

Our readers are well aware that water as found naturally is never absolutely free from dissolved impurities; and in ordinary cases it contains solid impurities derived both from the inorganic and organic kingdoms, together with gaseous substances; these latter being generally derived from the atmosphere.

By far the purest water which occurs in nature is rain-water, and if this be collected in a secluded district, and after the air has been well washed by previous rain, its purity is remarkable; the extraneous matter consisting of little else than a trace of carbonic acid and other gases dissolved from the air. In fact, such water is far purer than any distilled water to be obtained in commerce. The case is very different when the rain-water is collected in a town or densely populated district, more especially if the water has been allowed to flow over dirty roofs. The black and foully-smelling liquid popularly known as soft water is so rich in carbonaceous and organic constituents as to be of very limited use to the photographer; but by taking the precaution of fitting up a simple automatic shunt for diverting the stream until the roofs have been thoroughly washed, it becomes possible to insure a good supply of clean and serviceable soft water, even in London. Several forms of shunt have been devised, some of these being so complex as to offer every prospect of speedy disorganization; but a simple and efficient apparatus is figured in Engineering by a correspondent who signs himself "Millwright," and as we have thoroughly proved the value of an apparatus which is practically identical, we reproduce the substance of his communication.

A gentleman of Newcastle, a retired banker, having tried various filters to purify the rain-water collected on the roof of his house, at length had the idea to allow no water to run into the cistern until the roof had been well washed. After first putting up a hard-worked valve, the arrangement as sketched below has been hit upon. Now Newcastle is a very smoky place, and yet my friend gets water as pure as gin, and almost absolutely free from any smack of soot.



The sketch explains itself. The weight, W, and the angle of the lever, L, are such, that when the valve, V, is once opened it goes full open. A small hole in the can C, acts like a cataract, and brings matters to a normal state very soon after the rain ceases.

The proper action of the apparatus can only be insured by a careful adjustment of the weight, W, the angle through which the valve opens, and the magnitude of the vessel, C. It is an advantage to make the vessel, C, somewhat broader in proportion to its height than represented, and to provide it with a movable strainer placed about half way down. This tends to protect the cataract hole, and any accumulation of leaves and dirt can be removed once in six months or so. Clean soft water is valuable to the photographer in very many cases. Iron developer (wet plate) free from chlorides will ordinarily remain effective on the plate much longer than when chlorides are present, and the pyrogallic solution for dry-plate work will keep good for along time if made with soft water, while the lime which is present in hard water causes the pyrogallic acid to oxidize with considerable rapidity. Negatives that have been developed with oxalate developer often become covered with a very unsightly veil of calcium oxalate when rinsed with hard water, and something of a similar character occasionally occurs in the case of silver prints which are transferred directly from the exposure frame to impure water.

To the carbon printer clean rain-water is of considerable value, as he can develop much more rapidly with soft water than with hard water; or, what comes to the same thing, he can dissolve away his superfluous gelatine at a lower temperature than would otherwise be necessary.

The cleanest rain-water which can ordinarily be collected in a town is not sufficiently pure to be used with advantage in the preparation of the nitrate bath, it being advisable to use the purest distilled water for this purpose; and in many cases it is well to carefully distill water for the bath in a glass apparatus of the kind figured below.



A, thin glass flask serving as a retort. The tube, T, is fitted air-tight to the flask by a cork, C.

B, receiver into which the tube, T, fits quite loosely.

D, water vessel intended to keep the spiral of lamp wick, which is shown as surrounding T, in a moist condition. This wick acts as a siphon, and water is gradually drawn over into the lower receptacle, E.

L, spirit lamp, which may, in many cases, be advantageously replaced by a Bunsen burner.

A small metal still, provided with a tin condensing worm, is, however, a more generally serviceable arrangement, and if ordinary precautions are taken to make sure that the worm tube is clean, the resulting distilled water will be nearly as pure as that distilled in glass vessels.

Such a still as that figured below can be heated conveniently over an ordinary kitchen fire, and should find a place among the appliances of every photographer. Distilled water should always be used in the preparation of emulsion, as the impurities of ordinary water may often introduce disturbing conditions.—Photographic News.



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BLACK PHOSPHORUS.

By P. THENARD.

The author refers to the customary view that black phosphorus is merely a mixture of the ordinary phosphorus with traces of a metallic phosphide, and contends that this explanation is not in all cases admissible. A specimen of black or rather dark gray phosphorus, which the author submitted to the Academy, became white if melted and remained white if suddenly cooled, but if allowed to enter into a state of superfusion it became again black on contact with either white or black phosphorus. A portion of the black specimen being dissolved in carbon disulphide there remained undissolved merely a trace of a very pale yellow matter which seemed to be amorphous phosphorus.—Comptes Rendus.

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COMPOSITION OF STEEP WATER.

According to M. C. Leeuw, water in which malt has been steeped has the following composition:

Organic matter. 0.56 per cent. Mineral matter. 0.52 " —— Total dry matter. 1.08 " —— Nitrogen. 0.033 "

The mineral matter consists of—

Potash. 0.193 " Phosphoric acid. 0.031 " Lime. 0.012 " Soda. 0.047 " Magnesia. 0.016 " Sulphuric acid. 0.007 " Oxide of iron. traces. Chlorine and silica. 0.212 "

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SCHREIBER'S APPARATUS FOR REVIVIFYING BONE-BLACK.

We give opposite illustrations of Schreiber's apparatus for revivifying bone-black or animal charcoal. The object of revivification is to render the black fit to be used again after it has lost its decolorizing properties through service—that is to say, to free its pores from the absorbed salts and insoluble compounds that have formed therein during the operation of sugar refining. There are two methods employed—fermentation and washing. At present the tendency is to abandon the former in order to proceed with as small a stock of black as possible, and to adopt the method of washing with water and acid in a rotary washer.

Figs. 1 and 2 represent a plan and elevation of a bone-black room, containing light filters, A, arranged in a circle around wells, B. These latter have the form of a prism with trapezoidal base, whose small sides end at the same point, d, and the large ones at the filter. The funnel, E, of the washer, F, is placed in the space left by the small ends of the wells, so that the black may be taken from these latter and thrown directly into the washer. The washer is arranged so that the black may flow out near the steam fitter, G, beneath the floor. The discharge of this filter is toward the side of the elevator, H, which takes in the wet black below, and carries it up and pours it into the drier situated at the upper part of the furnace. This elevator, Figs. 3 and 4, is formed of two vertical wooden uprights, A, ten centimeters in thickness, to which are fixed two round-iron bars the same as guides. The lift, properly so-called, consists of an iron frame, C, provided at the four angles with rollers, D, and supporting a swinging bucket, E, which, on its arrival at the upper part of the furnace, allows the black to fall to an inclined plane that leads it to the upper part of the drier. The left is raised and lowered by means of a pitch-chain, F, fixed to the middle of the frame, C, and passing over two pulleys, G, at the upper part of the frame and descending to the mechanism that actuates it. This latter comprises a nut, I, acting directly on the chain; a toothed wheel, K, and a pinion, J, gearing with the latter and keyed upon the shaft of the pulleys, L and M. The diameter of the toothed wheel, K, is 0.295 of a meter, and it makes 53.4 revolutions per minute. The diameter of the pinion is 0.197 of a meter, and it makes 80 revolutions per minute. The pulleys, M and L, are 0.31 of a meter in diameter, and make 80 revolutions per minute. Motion is transmitted to them by other pulleys, N, keyed upon a shaft placed at the lower part, which receives its motion from the engine of the establishment through the intermedium of the pulley, O. The diameter of the latter is 0.385 of a meter, and that of N is 0.58. They each make 43 revolutions per minute.



The elevator is set in motion by the simple maneuver of the gearing lever, P, and when this has been done all the other motions are effected automatically.

The Animal Black Furnace.—This consists of a masonry casing of rectangular form, in which are arranged on each side of the same fire-place two rows of cast-iron retorts, D, of undulating form, each composed of three parts, set one within the other. These retorts, which serve for the revivification of the black, are incased in superposed blocks of refractory clay, P, Q, S, designed to regularize the transmission of heat and to prevent burning. These pieces are kept in their respective places by crosspieces, R. The space between the retorts occupied by the fire-place, Y, is covered with a cylindrical dome, O, of refractory tiles, forming a fire-chamber with the inner surface of the blocks, P, Q, and S. The front of the surface consists of a cast-iron plate, containing the doors to the fire-place and ash pan, and a larger one to allow of entrance to the interior to make repairs.

One of the principal disadvantages of furnaces for revivifying animal charcoal has been that they possessed no automatic drier for drying the black on its exit from the washer. It was for the purpose of remedying this that Mr. Schreiber was led to invent the automatic system of drying shown at the upper part of the furnace, and which is formed of two pipes, B, of undulating form, like the retorts, with openings throughout their length for the escape of steam. Between these pipes there is a closed space into which enters the waste heat and products of combustion from the furnace. These latter afterward escape through the chimney at the upper part.

In order that the black may be put in bags on issuing from the furnace, it must be cooled as much as possible. For this purpose there are arranged on each side of the furnace two pieces of cast iron tubes, F, of rectangular section, forming a prolongation of the retorts and making with them an angle of about 45 degrees. The extremities of these tubes terminate in hollow rotary cylinders, G, which permit of regulating the flow of the black into a car, J (Fig. 1), running on rails.

From what precedes, it will be readily understood how a furnace is run on this plan.

The bone-black in the hopper, A, descends into the drier, B, enters the retorts, D, and, after revivification, passes into the cooling pipes, F, from whence it issues cold and ready to be bagged. A coke fire having been built in the fire-place, Y, the flames spread throughout the fire chamber, direct themselves toward the bottom, divide into two parts to the right and left, and heat the back of the retorts in passing. Then the two currents mount through the lateral flues, V, and unite so as to form but one in the drier. Within the latter there are arranged plates designed to break the current from the flames, and allow it to heat all the inner parts of the pipes, while the apertures in the drier allow of the escape of the steam.

By turning one of the cylinders, G, so as to present its aperture opposite that of the cooler, it instantly fills up with black. At this moment the whole column, from top to bottom, is set in motion. The bone-black, in passing through the undulations, is thrown alternately to the right and left until it finally reaches the coolers. This operation is repeated as many times as the cylinder is filled during the descent of one whole column, that is to say, about forty times.

With an apparatus of the dimensions here described, 120 hectoliters of bone-black may be revivified in twenty four hours, with 360 to 400 kilogrammes of coke.—Annales Industrielles.

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[Continued from SUPPLEMENT, No. 330, page 5264.]



SOAP AND ITS MANUFACTURE, FROM A CONSUMER'S POINT OF VIEW.

In our last article, under the above heading, the advantages to be gained by the use of potash soap as compared with soda soap were pointed out, and the reasons of this superiority, especially in the case of washing wool or woolen fabrics, were pretty fully gone into. It was also further explained why the potash soaps generally sold to the public were unfit for general use, owing to their not being neutral—that is to say, containing a considerable excess of free or unsaponified alkali, which acts injuriously on the fiber of any textile material, and causes sore hands if used for household or laundry purposes. It was shown that the cause of this defect was owing to the old-fashioned method of making potash or soft soap, by boiling with wood ashes or other impure form of potash; but that a perfectly pure and neutral potash soap could readily be made with pure caustic potash, which within the last few years has become a commercial article, manufactured on a large scale; just in the same manner as the powdered 98 per cent. caustic soda, which was recommended in our previous articles on making hard soap without boiling.

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