SCIENTIFIC AMERICAN SUPPLEMENT NO. 388
NEW YORK, June 9, 1883
Scientific American Supplement. Vol. XV., No. 388.
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.—Farcot's Improved Woolf Compound Engine.—4 figures.
The "Swallow," a New Vehicle.
Boring an Oil Well.
A Cement Reservoir.—2 figures.
II. TECHNOLOGY.—Iron and Steel.—By BARNARD SAMUELSON. The world's production of pig iron.—Wonderful uses and demands for iron and steel.—Progress of Bessemer steel.—Latest improvements in iron making.—Honors and rewards to inventors. —Growth of the Siemens-Martin process.—The future of iron and steel.—Relations between employers and workmen.
Machine for Grinding Lithographic Inks and Colors.—1 figure.
A new Evaporating apparatus.—2 figures.
Photo Plates.—Wet and Dry.
Gelatino Bromide Emulsion with Bromide of Zinc.
The Removal of Ammonia from Crude Gas.
III. MEDICINE AND HYGIENE.—The Hair, its Uses and its Care. The Influence of Effective Breathing in Delaying the Physical Changes Incident to the Decline of Life, and in the Prevention of Pneumonia. Consumption, and Diseases of Women.—By DAVID WARK. M.D.—Pneumonia.—The true first stage of Consumption. The development of tubercular matter in the blood.—The value of cod-liver oil in the prevention of consumption.—The influence of normal breathing on the female generative organs—Showing how the breathing powers may be developed.—The effects of adequate respiration in special cases.
Vital Discoveries in Obstructed Air and Ventilation.
IV. ELECTRICITY.—The Portrush Electric Railway, Ireland.—By Dr. EDWARD HOPKINSON.
The Thomson-Houston Electric Lighting System.—4 figures.
A Modification of the Vibrating Bell.—2 figures.
V. CHEMISTRY.—Acetate of Lime.
Reconversion of Nitroglycerine into Glycerine. By C.L. BLOXAM.
Carbonic Acid and Bisulphide of Carbon. By JOHN TYNDALL.
VI. AGRICULTURE AND HORTICULTURE.—Propagation of Maple Trees.
Ravages of a Rare Scolytid Beetle in the Sugar Maples of Northeastern New York.—Several figures.
The Red Spider. 4 figures.
VII. NATURAL HISTORY.—The Recent Eruption of Etna.
The Heloderma Horridum.—Illustration.
VIII. ARCHITECTURE.—Design for a Villa.—Illustration.
IX. BIOGRAPHY.—William Spottiswoode.—Portrait.
X. MISCELLANEOUS.—Physics without Apparatus.—Illustration.
The Travels of the Sun.
FARCOT'S IMPROVED WOOLF COMPOUND ENGINE.
In a preceding article, we have described a ventilator which is in use at the Decazeville coal mines, and which is capable of furnishing, per second, 20 cubic meters of air whose pressure must be able to vary between 30 and 80 millimeters.
In order to actuate such an apparatus, it was necessary to have a motor that was possessed of great elasticity, and that nevertheless presented no complications incompatible with the application that was to be made of it.
In the ventilation of mines it has been demonstrated that the theoretic power in kilogrammes necessary to displace a certain number of cubic meters of air, at a pressure expressed in millimeters of water, is obtained by multiplying one number by the other. Applying this rule to the case of 20 cubic meters under a hydrostatic pressure of 30 millimeters, we find:
20 x 30 = 600 kilogrammeters.
In the case of a pressure of 80 millimeters, we have:
20 x 80 = 1,600 kilogrammeters.
If we admit a product of 50 per cent., we shall have in the two cases, for the power actually necessary:
600 —— = 1,200 kilogrammeters, or 16 H.P. 0.05
1,600 ——- = 3,200 kilogrammeters, or 43 H.P. 0.05
Such are the limits within which the power of the motor should be able to vary.
After successively examining all the different systems of engines now in existence, and finding none which, in a plain form, was capable of fulfilling the conditions imposed, Mr. E.D. Farcot decided to study out one for himself. Almost from the very beginning of his researches in this direction, he adopted the Woolf system, which is one that permits of great variation in the expansion, and one in which the steam under full pressure acts only upon the small piston. There are many types of this engine in use, all of which present marked defects. In one of them, the large cylinder is arranged directly over the small one so as to have but a single rod for the two pistons; and the two cylinders have then one bottom in common, which is furnished with a stuffing-box in which the rod moves. With this arrangement we have but a single connecting rod and a single crank for the shaft; but, the stuffing-box not being accessible so that it can be kept in a clean state, there occur after a time both leakages of steam and entrances of air.
Mr. Farcot has further simplified this last named type by suppressing the intermediate partition, and consequently the stuffing-box. The engine thus becomes direct acting, that is to say, the steam acts first upon the lower surface of the small piston during its ascent, and afterward expands in the large cylinder and exerts its pressure upon the upper surface of the large piston during its descent. Moreover, the expansion may be begun in the small cylinder, thanks to the use of a slide plate distributing valve, devised by the elder Farcot and slightly modified by the son.
As the volume comprised between the two pistons varies with the position of the latter, annoying counter-pressures might result therefrom had not care been taken to put the chamber in communication with a reservoir of ten times greater capacity, and which is formed by the interior of the frame. This brings about an almost constant counter-pressure.
The type of motor under consideration, which we represent in the accompanying plate, is possessed of remarkable simplicity. The number of parts is reduced to the extremest limits; it works at high speed without perceptible wear; it does not require those frequent repairs that many other cheap engines do; and the expansion of the steam is utilized without occasioning violent shocks in the parts which transmit motion. Finally, the plainness of the whole apparatus is perfectly in accordance with the uses for which it was devised.
Details of Construction.—Figs. 1 and 2 represent the motor in vertical section made in the direction of two planes at right angles. Figs. 3 and 4 are horizontal sections made respectively in the direction of the lines 1-2 and 3-4.
The frame, which is of cast iron and entirely hollow, consists of two uprights, B, connected at their upper part by a sort of cap, B, which is cast in a piece with the two cylinders, C and c. The whole rests upon a base, B squared, which is itself bolted to the masonry foundation.
Each of the uprights is provided internally with projecting pieces for receiving the guides between which slides the cross-head, g, of the piston rod. The slides terminate in two lubricating cups designed for oiling the surfaces submitted to friction.
The cross-head carries two bearings, g, to which is jointed the forked extremity, D, of the connecting rod, whose opposite extremity receives a strap that embraces the cranked end of the driving shaft, A. It will be remarked that the crank, A, and the bearings, g, are very long. The end the inventor had in view in constructing them thus was to diminish friction.
To the shaft, A, are keyed the coupling disks, Q, which are cast solid at a portion of their circumference situated at 180 deg. with respect to the parts, A squared, of the cranked shaft, the object of this being to balance the latter as well as a portion of the connecting rod, D.
The shaft, A, also receives the eccentric, E, of the slide valve, the rod, e, of which is jointed to the slide valve rod through the intermedium of a cross-head, e, analogous to that of the pistons, and which, like the latter, runs on guides held by the support, b.
The two pistons, p and P, are mounted very simply on the rod, T, as shown in Fig. 1, and slide in cylinders, c and C, whose diameters are respectively equal to 270 and 470 millimeters.
The slide valve box, F, is bolted to the cap-piece, B, as seen in Fig. 4. As for the slide valve, t, its arrangement may be distinguished in section in Fig. 2. Its eccentric is keyed at 170 deg. so as to admit steam into the small cylinder during the entire travel, which latter is 470 mm.
To permit of the expansion beginning in the small cylinder, Mr. Farcot has added a sliding plate, t, which abuts at every stroke against the stops, s. These latter are affixed to the rod, S, whose lower extremity is threaded, and which may be moved vertically, as slightly as may be desired, through the medium of the pinions, S, when the hand-wheel, V, is revolved. A datum point, v, and a graduated socket, v, allow the position of the stops, s, and consequently the degree of expansion, to be known.
Steam is introduced into the small cylinder through the conduit, i, and its passage into the large one is effected through the conduit, f. The escape into the interior of the frame is effected, after expansion, through the horizontal conduit, h. The pipe, H, leads this exhaust steam to the open air.
The pipe, I, leads steam into the jacket, C, of the large cylinder, this latter being provided in addition with a casing of wood, C squared, so as to completely prevent chilling.
The regulator, R, is after the Buess pattern, and is set in motion by a belt which runs over the pulleys, a and a. It is mounted upon a distributing box, R, to which steam is led from the boiler by the pipe, r. After traversing this box, the steam enters the slide valve box through the pipe, r squared, its admission thereto being regulated by the hand-wheel, R squared, which likewise serves for stopping the engine.
The cocks, x, are fixed at the base of the uprights, B, for drawing from the frame the condensed water that has accumulated therein.
The lubricating apparatus, V, which communicates, through the tube, u, with the steam port, r, permits oil to be sent to the large and small cylinders through the tubes, u and u squared.
Mr. Farcot has recently adapted this type of motor to the direct running of electric machines that are required to make 400 revolutions per minute.—Publication Industrielle.
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IRON AND STEEL.
At the recent meeting of the Iron and Steel Institute, London, the president-elect (Mr. Bernard Samuelson, M.P.), delivered the following inaugural address:
THE WORLD'S PRODUCTION OF PIG IRON.
He showed that the world's production of pig iron has increased in round numbers from 10,500,000 tons in 1869 to 20,500,000 tons in 1882. The blast furnaces of 1869 produced on the average a little over 180 tons per week, with a temperature of blast scarcely exceeding 800 deg. Fahr. The consumption of coke per ton of iron varied from 25 to 30 cwt. To-day our blast furnaces produce on the average upward of 300 tons per week.
The Consett Company have reached a production of 3,400 tons in four weeks, or 850 tons per week, and of 134 tons in one day from a single furnace.
From the United States we have authentic accounts of an average production of 1,120 tons per furnace per week having been attained, and that even this great output has lately been considerably exceeded there. Both as to consumption of fuel and wear and tear, per ton of iron produced, these enormous outputs are attended with economy.
HEAT OF THE BLAST.
In the case of the Consett furnace they were obtained although the heat of the blast was under 1,100 deg. Fahr., while heats of 1,500 deg. to 1,600 deg. are not uncommon at the present day in brick stoves, thanks to the application of the regenerating principle of ex-president Sir W. Siemens.
But an economy which promises to be of great importance is now sought in the recovery and useful application of those constituents of coal which, in the coking process, have hitherto been lost; or, as an alternative, in a similar recovery in those cases in which the coal is charged in a raw state into the blast furnace, as is the practice in Scotland and elsewhere. This recovery of the hydrocarbons and the nitrogen contained in the coal, and their collection as tar and ammoniacal liquors, and subsequent conversion into sulphate of ammonia as to the latter, and into the various light and heavy paraffin oils and the residual pitch as to the former, have now been carried on for a considerable time at two of the Gartsherrie furnaces; and they are already engaged in applying the necessary apparatus to eight more furnaces. In the coke oven the recovery of these by-products—if that name can be properly applied to substances which yield the most brilliant colors, the purest illuminants, and the flesh-forming constituents supplied by the vegetable world—would appear at first sight to be simpler; but it has presented its own peculiar difficulties; the chief of which was, or was believed to be, a deterioration in the quality of what has hitherto been the principal, but what may, perhaps, come to be regarded hereafter as the residual product, namely, the coke. But the more recent experience of Messrs. Pease, at Crook, appears not to justify this opinion. You will see on our table specimens of the coke produced in the Carves-Simon oven, yielding 75 to 77 per cent. of coke from the Pease's West coal, which they have now had at work for several months. Twenty-five of these ovens are at work, and the average yield of ammoniacal liquor per ton of coal has been 30 gallons of a strength of 7 deg. Twaddell, valued at 1d. per gallon at the ovens; the quantity of tar per ton has been 7 gallons, valued at 3d. per gallon. These products would therefore realize 4s. 3d. per ton of coal. Of course the profit on the ton of coke is considerably more, and to this has to be added the value of the additional weight of coke, which in the ordinary beehive ovens from coal of the same quality is only 60 per cent. or in beehive ovens having bottom flues about 66 per cent., while in the Carves ovens it is, as I have said, upward of 75 per cent. Against these figures there is a charge of 1s. 4d. per ton of coke for additional labor, including all the labor in collecting the by-products; the interest on the first cost of the plant, which is considerable, and probably some outlay for repairs in excess of that in the case of ordinary ovens, has also to be charged. Mr. Jameson takes credit for the combustible gas, which is used up in the Carves ovens, but which remains over in his process, and is available, though not nearly all consumed, in raising steam for the various purposes of a colliery, including, no doubt, before long, the generation of electricity for its illumination. It is right to state that prior to 1879 Mr. Henry Aitken had applied bottom flues for taking off the oil and ammoniacal water to beehive ovens at the Almond Ironworks, near Falkirk. He states that the largest quantity of oil obtained was eleven gallons, the specific gravity varying from 0.925 to 1.000, and that the water contained a quantity of ammonia fully equal to 51/2 lb. of sulphate of ammonia to the ton of coal coked. The residual permanent or non-condensed gases were allowed to issue from the end of the condenser pipe, and were burnt for light in the engine-houses, but it was intended to force them into the oven again above the level of the coke. Owing to the works being closed, nothing has been done with these ovens for some years. I may mention, by the way, that it is proposed to apply the principle of Mr. Jameson's process to the recovery of oil and ammonia from the smouldering waste heaps at the pit-bank, by the introduction into these of conduits resembling those which he applies to the bottom of the beehive oven. There is every reason to expect that one or more of these various methods of utilizing valuable products which are at present lost will be carried to perfection, and will tend to cheapen the cost at which iron can be produced, and still further to increase its consumption for all the multifarious purposes to which it is applied.
WONDERFUL USES AND DEMAND FOR IRON AND STEEL.
But the world's annual production of 20,000,000 tons of pig iron is itself sufficiently startling, and without attempting to present to you the statistics of all its various uses—for which, in fact, we do not possess the necessary materials—the increased consumption of more than 9,000,000 tons since 1869 becomes conceivable when we consider how some of the great works in which it is employed have been extending during that or even a shorter interval. And of these I need only speak of the world's railways, of which there were in 1872 155,000 miles, and in 1882 not less than 260,000, but probably more nearly 265,000 miles. In the United States alone about 60,000 miles of railway have been built since 1869—the year, I may remind you in passing, in which the Atlantic and Pacific States of the Union were first united by a railway; while in our Indian Empire the communication between Calcutta and Bombay was not completed till the following year.
The substitution of iron and steel for wood in the construction of ships, and the enormous increase in the tonnage of the world, in spite of the economy arising from the employment of steamers in place of sailing ships, is perhaps the element of increased consumption next in importance to that of railways. I do not think that the materials are available for estimating with any accuracy the amount of this increase, but I believe I am rather understating it if I take the consumption of iron and steel used last year throughout the world in shipbuilding as having required considerably more than 1,000,000 tons of pig iron for its production, and that this is not far short of four times the quantity used for the same purpose before 1870. And so all the other great works in which iron and steel are employed have increased throughout the world. It would be tedious to indicate them all.
Among those which rank next in importance to the preceding, I will only name the works for the distribution of water and gas, which in this country and in the United States have been extended in a ratio far greater than that of the increase of the population, and which, since the conclusion of the Franco-German war, and the consolidation of the German and Italian States, are now to be found in almost every European town of even secondary importance; and bridges and piers, in the construction of which iron has almost entirely superseded every other material.
It is difficult to imagine what would have been the state of the iron industry in this country if we had been called upon to supply our full proportion of the enormously increased demand for iron. To meet that proportion, the British production of pig iron should have been close on 11,000,000 tons in 1882, a drain on our mineral resources which cannot be replaced, and which, especially if continued in the same ratio, would have been anything but desirable. Fortunately, as I am disposed to think, other countries have contributed more than a proportionate amount to the increase in the world's demand; and, paradoxical as it may appear, it is possible that, to this country at least, the encouragement given by protective duties to the production of iron abroad may have been a blessing in disguise.
PROGRESS OF BESSEMER STEEL.
To speak of the enormous increase in the production of steel by the introduction of the Bessemer process has become a commonplace on occasions like the present, and yet I doubt whether its real dimensions are generally known or remembered. In 1869 the manufacture of Bessemer steel had already acquired what was then looked upon as a considerable development in all the principal centers of metallurgical industry, except the United States, but including our own country, Germany, France, and Austria, and the world's production in that year was 400,000 tons. Last year it was over 5,000,000 tons, and it has doubled in every steel-producing country during the last four years, except in France, where, during this latter period, the increase has not been much more than one-fourth. What is almost as remarkable as the enormous increase in the production of Bessemer steel is the great diminution in its cost. In the years preceding 1875, the price of rails manufactured from Bessemer ingots fluctuated between L10 and L18 per ton, and I remember Lord George Hamilton when he was Under-Secretary for India of Lord Beaconsfield's administration in 1875 or 1876, congratulating himself on his good fortune in having been able to secure a quantity of steel rails for the Indian government at L13 per ton. Within the last three years we have seen them sold under L4 10s. in this country, and L5 10s. in Germany and Belgium.
LATEST IMPROVEMENTS IN IRON MAKING.
This great reduction is the cumulative result of a number of concurrent improvements, partly in the conversion of the iron, and partly in the subsequent treatment of the ingot steel. In most of the great steelworks the iron is no longer remelted, but is transferred direct from the blast furnace to the converter, a practice which originated at Terre-Noire, and was long considered in this country to be incompatible with uniformity in the quality of the steel produced. The turn-out of the converter plant has been gradually increased in this country to more than four times that of fourteen years ago, while the practice of the United States is stated by a recent visitor to have reached such an astounding figure that I am afraid to quote it without confirmation; but the greatest economy arises no doubt in the labor and fuel employed in the mill.
Cogging has taken the place of hammering. Even wash-heating will be, if it is not already, generally dispensed with by the soaking process of our colleague, Mr. Gjers, which permits of the ingot, as it leaves the pit, being directly converted into a rail.
STEEL RAILS 150 FEET LONG.
An extract from a letter addressed to me by our colleague, Mr. E.W. Richards, will describe better than any words of mine the perfection at which steel rail mills have arrived. He says, "Our cogging rolls are 48 in. diameter, and the roughing and finishing rolls are 30 in. diameter. We roll rails 150 feet long as easily as they used to roll 21 feet. Our ingots are 151/2 inches square, and weigh from 25 to 30 cwts. according to the weight of rail we have to roll. These heavy ingots are all handled by machinery. We convey them by small locomotives from the Bessemer shop to the heating furnaces, and by the same means from the heating furnaces to the cogging rolls.
So quickly are these ingots now handled that we have given up second heating altogether, so that after one heat the ingot is cogged from 151/2 inches square down to 8 inches square, then at once passed on to the roughing and finishing rolls, and finished in lengths, as I have said before, of 150 ft., then cut at the hot saws to the lengths given in the specifications, and varying from 38 ft. to about 21 ft. The 38 ft. lengths are used by the Italian 'Meridionali' Railway Company, and found to give very satisfactory results." I need scarcely say that in a mill like this, the expenditure of fuel and labor and the loss by waste caused by crop ends are reduced to a minimum.
The enormous production of steel has required the importation of large quantities of iron ore of pure quality from Spain, Algeria, and elsewhere, into this country, France, Belgium, Germany, and the United States; and these supplies have contributed greatly to the reduction in the price of steel to which I have referred, and what is, perhaps, of equal importance, they have prevented the great fluctuations of price which formerly prevailed. In 1869 this trade was in its infancy, and almost confined to the importation of the Algerian ores of Mokta el Hadid into France, while in 1882 Bilbao alone exported 3,700,000 tons of hematite ores to various countries to which the exports from the south of Spain, Algeria, Elba, Greece, and other countries have to be added. Great Britain alone imported 3,000,000 tons of high class, including manganiferous iron ores last year.
It is questionable whether the mines of pure iron existing in Europe would long bear a drain so great and still increasing; but happily the question no longer presses for an answer, because the problem of obtaining first-class steel from inferior ores has been solved by the genius of our colleagues, Mr. Snelus and Messrs. Thomas and Gilchrist, and by the practical skill and indomitable resolution of Mr. Windsor Richards. It is no part of the duty of the Institute to assign to each of these gentlemen his precise share in the development of the basic process. Whatever those shares may be, I feel sure you will agree with your council as to the propriety of their having awarded a Bessemer medal to two of these gentlemen—Messrs. Snelus and Thomas—to Mr. Snelus as the first who made pure steel from impure iron in a Bessemer converter lined with basic materials; to Mr. Thomas, who solved the same problem independently, and so clearly demonstrated its practicability to Mr. Richards by the trials at Blaenavon, as to have led that gentleman to devote all his energies and the great resources of the Eston Works to the task of making it what it now is, a great commercial success. All difficulties connected with the lining of the converter and in insuring a durability of the bottom, nearly, if not quite, equal to that in the acid process, appear now to have been successfully surmounted, and I am informed by Mr. Gilchrist that the present production of basic steel in this country and on the Continent is already at the rate of considerably more than 500,000 tons per annum, and that works are now in course of construction which will increase this quantity to more than a million tons.
Our members will have the opportunity of seeing the process at work during their visit to Middlesbrough, at the Eston Works of Messrs. Bolckow, Vaughan & Co., which are now producing 150,000 tons per annum of steel of the highest quality from the phosphoretic Cleveland ores; and also at the North-Eastern Steel Company's Works. I believe it is the intention of the latter company to make a pure, soft steel suitable for plates, for which, according to the testimony of Mons. Delafond, of Creuzot, and others, the basic steel is peculiarly suitable on account of its remarkable regularity. I shall have the pleasure of presenting to Mr. Snelus the medal which he has so well deserved.
HONORS AND REWARDS TO INVENTORS.
The presentation to Mr. Thomas is deferred. His arduous labors having affected his health, he is at present in Australia, after having, I am happy to say, received great advantage from the voyage; and his mother, justly proud of his merits, and appreciating fully the value of their recognition by the award which we have made, has requested us not to present the medal by proxy, but to await the return of her son, in order that it may be handed to him in person. But honors, whether conferred by the Crown, by learned bodies, or, as in this case, by the colleagues of the recipient, though they stimulate invention, are by themselves not always sufficient to encourage inventors to devote their labor to the improvements of manufactures or to induce capitalists to assist inventors in the prosecution of costly experiments; and it is on this account that the protection of inventions by patent is a public advantage. The members of our profession, unlike some others, have not been eager to apply for patents in the case of minor inventions; on the contrary, they have freely communicated to each other the experience as to improvement in detail which have resulted from their daily practice. It has been well said that all the world is wiser than any one man in it, and this free interchange of our various experiences has tended greatly to the advancement of our trade. But new departures, like the great invention of Sir H. Bessemer, and important improvements like the basic process, require the protection of patents for their development.
THE PATENT LAWS.
The subject of the patent laws is, therefore, of interest to us, as it is to other manufacturers. You are aware that the Government has introduced a bill for amending these laws. If that bill should pass, it will effect several important changes. It will, in the first place, enable a poor man to obtain protection for an invention at a small cost; secondly, it will make it more difficult than at present for a merely pretended invention to obtain the protection and prestige of a patent; thirdly, it will promote the amalgamation of mutually interdependent inventions by the clause which compels patentees to grant licenses; and, lastly, it will enable the Government to enter into treaties with other powers for the international protection of inventions. If you should be of opinion that these are objects deserving of your support, I hope that you will induce your representatives in the House of Commons to do all that is in their power to assist the Government in passing them into law.
GROWTH OF THE SIEMENS-MARTIN PROCESS.
The growth of the open hearth or what is known as the Siemens-Martin process of making steel, during the interval from 1869 to the present time, has been no less remarkable than that of the Bessemer process; for though it has not attained the enormous dimensions of the latter, it has risen from smaller beginnings. Mr. Ramsbottom started a small open-hearth plant at the Crewe Works of the London and North-Western Railway, in 1868, for making railway tires, and the Landore Works were begun by Sir W. Siemens in the same year. On the Continent there were a few furnaces at the works of M. Emile Martin, at the Firming Works, and at Le Creuzot. None of these works, I believe, possessed furnaces before 1870, capable of containing more than four-ton charges, ordinarily worked off twice in twenty-four hours. The ingots weighed about 6 cwt., and the largest steel casting made by this process, of which I can find any account, did not exceed 10 cwt. At the present day, we have furnaces of a capacity of from 15 to 25 tons, and by combining several furnaces, single ingots weighing from 120 to 125 tons have been produced at Le Creuzot. The world's production of open-hearth steel ingots for ship and boiler plates, propeller shafts, ordnance, wheels and axles, wire billets, armor plates, castings of various kinds, and a multiplicity of other articles, cannot have been less than from 800,000 to 850,000 tons in 1882.
The process itself has followed two somewhat dissimilar lines. In this country, iron ores of a pure quality are dissolved in a bath of pig iron, with the addition of only small quantities of scrap steel and iron. At Le Creuzot large quantities of wrought iron are melted in the bath. This iron is puddled in modified rotating Danks furnaces containing a charge of a ton each. The furnaces have a mid-rib dividing the product into two balls of 10 cwt., which are shingled under a 10-ton hammer. The iron is of exceptional purity, containing less than 0.01 per cent. of phosphorus and sulphur. I should add that the two rotating furnaces produce 50 tons of billets in twenty-four hours.
PRESENT PRODUCTION OF WROUGHT IRON.
Meanwhile, the world's production of wrought iron has not been stationary. I cannot give very accurate figures, as the statistics of some countries are incomplete, while in others the output of puddled bar only, and not that of finished iron, has been ascertained. The nearest estimate which I can arrive at is a production increased from about 5,000,000 tons in 1869 to somewhat over 8,000,000 tons of finished iron in 1882; an increase all the more remarkable when it is considered that at the present time iron rails have been almost entirely superseded by steel. It is due, no doubt, in part to the extensive use of iron plates and angles in shipbuilding; but, apart from these, and from bars for the manufacture of tin-plates, the consumption has increased for the numberless purposes to which it is applied in the world's economy.
PROGRESS OF PUDDLING.
There has been no striking improvement in the manufacture of puddled iron, partly on account of the impression that it is doomed to be superseded by steel. Mechanical puddling has made but little progress, and few of the attempts to economize fuel in the puddling furnace, by the use of gas or otherwise, have been successful. I would, however, draw attention to the remarkable success which has attended the use of the Bicheroux gas puddling and heating furnaces at the works of Ougree, near Liege. The works produce 20,000 tons of puddled bars per annum, in fifteen double furnaces. The consumption of coal per ton of ordinary puddled bar is under 11 cwt., and per ton of "fer a fin grain" (puddled steel, etc.) 16 cwt. The gas is produced from slack, and the waste heat raises as much steam as that from an ordinary double furnace. The consumption of pig iron per ton of puddled bar was rather less than 211/2 cwts. for the year 1882; and that of "mine" for fettling was 33 lb. The repairs are said to be considerably less than in the ordinary furnaces, and the puddlers earn from 25 to 30 per cent. more at the same tonnage rate. I have already mentioned the large consumption, reckoned in tons of pig iron, of the materials for shipbuilding.
GROSS OF IRON AND STEEL SHIP BUILDING.
It may be useful to add that the gross tonnage of iron vessels classed during 1882 by the three societies of Lloyd's, the Liverpool Registry, and the Bureau Veritas was 1,142,000, and of steel 143,000 tons, and that the proportion of steel to iron vessels is increasing from year to year. I am informed by our colleague, Mr. Pearce, of Messrs. Elder's firm, that the largest vessel built by them in 1869 was an iron steamer, of 3,063 tons gross, with compound engines of 3,000 horse power, working at 60 lb. pressure; speed, 14 knots.
A GIGANTIC STEAMER.
The largest vessel now on the ways is the Oregon, of 7,400 tons gross, and 13,000 horse power; estimated speed, 18 knots. The superficial area of the largest plates in the former was 221/2 square feet; that of the largest plate in the latter is 206 square feet. The Oregon is an iron vessel, but some of the largest vessels now being built by Mr. Pearce's firm are of steel.
The information which I have obtained from Messrs. Thomson, of Glasgow, is especially emphatic as to the supersession of iron by steel in the construction of ships. They say that large steel plates are as cheap as iron ones, and that they have never had one bad plate or angle in steel. This is confirmed by Mr. Denny, who says: "Whenever our shipwrights or smiths have to turn out anything particularly difficult in shape, and on which much 'work' has to be put, they will get hold of a piece of steel if they can."
REMARKABLE MACHINERY AND TOOLS.
It will be readily understood that the rolls, the hammers, the machinery for punching, drilling, planing, etc., used in the manufacture and preparation of plates and angles for shipbuilding and armor plates are on a scale far different at the present date from what they were in 1869. Perhaps the most striking examples of powerful machinery for these purposes are the great Creuzot hammer, the falling mass of which has recently been increased to 100 tons, and the new planing machines at the Cyclops Works, which weigh upward of 140 tons each, for planing compound armor plates 19 in. thick and weighing 57 tons.
THE FUTURE OF IRON AND STEEL.
Some of the eminent men who have preceded me in this chair have made their inaugural address the occasion for a forecast of the improvements in practice and the developments in area of the great industry in which we are engaged. Several of these forecasts have been verified by the results; in other cases they have proved to be mistaken; nor need this excite surprise. I believe that few would have predicted, when the consideration of the subject was somewhat unfortunately deferred through want of time at our Paris meeting of 1878, that the basic process would so speedily prove itself to be of such paramount value as we now know it to possess. On the other hand, the extinction of the old puddling process has long been the favorite topic of one of our most practical ex-presidents, and I have shown you by figures that the process is not only not yet dead, but that the manufacture of wrought iron is actually flourishing side by side with that of its younger brother, steel. How much longer this may continue to be the case it would not be easy to foretell, but there can be little doubt that, just as for rails steel has superseded iron as being cheaper and vastly more durable, so it will be in regard to plates for constructive purposes, and especially for shipbuilding. It is now an ascertained fact that steel ships are as cheap, ton for ton of carrying capacity, as iron ones, and it is probable that as the demand for, and consequently the production of, steel plates increases, steel ships will become cheaper than those built of iron; but, what is more important, they have been proved to be safer, and no time can long elapse before this will tell on the premiums of insurance. Steel forgings also are superseding, and must to an increasing extent, supersede iron; while it is probable that the former will in their turn be replaced for many purposes by the beautiful solid steel castings which are now being produced by the Terre-Noire Company in France, the Steel Company of Scotland, and other manufacturers, by the Siemens-Martin process. On this subject I believe Mr. Parker can give us valuable information; and on a cognate branch, namely, the production of steel castings from the Bessemer converter, an interesting paper will be submitted to us by Mr. Allen at our present meeting.
I may here mention incidentally, that I have of late had occasion to make trials on a considerable scale of edge tools made from Bessemer steel, which show that, except perhaps in the case of the finest cutlery, there is no longer any occasion to resort to the crucible for the production of this quality of steel.
RAILWAY DEMAND FOR IRON AND STEEL.
But it is in the further development of the world's railways that we must mainly look in the future, as in the past, for the support of our trade. In India the railway between Calcutta and Bombay was only completed in 1870, and at the present time, with a population of 250,000,000, it has less than 10,000 miles of railway, while the United States, with only 50,000,000, possesses more than 100,000 miles. In other words, the United States have fifty times as many miles of railway in relation to the population as India. Even Russia in Europe has 14,000 miles, or, in relation to its population, nearly five times as great a mileage as our Indian Empire; and the existing Indian railways are so successful pecuniarily, and give such promise of contributing to the wealth of the Indian people—or perhaps it would be more just to say, of rescuing them from their present state of poverty and depression—that it should be the aim of those who are responsible for the well-being of our great dependency to give to its railways the utmost and most rapid development.
As to the United States themselves, I look upon their railways as a little more than the main arteries from which an indefinitely large circulating system will branch out. Besides these countries I need only allude to the Dominion of Canada, whose vast territory bids fair to rival that of the United States in agricultural importance, to our Australian colonies, to Brazil, and other countries in which railways are still comparatively in their infancy, to show that, quite apart from the renewal of existing lines, the world's manufacture of rails has an enormous future before it.
RELATIONS BETWEEN EMPLOYERS AND WORKMEN.
I look on the excellent feeling which happily prevails between the employers and the workmen in our great industry as another of the most important elements of its future prosperity. It confers honor on all concerned that by our Boards of Conciliation and Arbitration, ruinous strikes, and even momentary suspensions of labor, are avoided; and still more that masters like our esteemed Treasurer, Mr. David Dale, should deserve, and that large bodies of workmen should have the manliness and discernment to bestow on him, the confidence implied in choosing him so frequently as an arbitrator. I believe that similar friendly relations exist in some, at any rate, of the other great centers of the iron and steel industries, and that although our methods may not be adapted to the habits of all, there is no country in which some way does not exist, or may not be found, to avoid those contests which were so fatal to our prosperity in former days. Lastly I regard as one of the most hopeful signs of the future the increased estimate of the value of science entertained by our practical men. In this respect we may claim with pride that the Iron and Steel Institute has been the pioneer, at any rate, so far as this country is concerned. But the conviction that the elements of science should be placed within the reach of those who occupy a humbler position in the industrial hierarchy than we do who are assembled here is rapidly spreading among us. The iron manufacturers of Westphalia have been the first to found an institution in which the intelligent and ambitious ironworker can qualify himself by study for a higher position, and I hope when this Institute visits Middlesbrough in the autumn, some progress will have been made in that locality toward the establishment of a similar school. Other districts will doubtless follow, and the result will be, to quote the words of Sir W. Siemens on a late occasion, that "by the dissemination of science a higher spirit will take possession of our artisans; that they will work with the object of obtaining higher results, instead of only discussing questions of wages." It is on the mutual co-operation in this spirit of all the workers of every grade in our great craft that we may build the hope—nay, that we may even cherish the certain expectation—of placing it on even a higher eminence than that which it has already attained.
* * * * *
THE "SWALLOW," A NEW VEHICLE.
The graceful vehicle shown in the accompanying cut is much used in Poland and Russia, and we believe that it has already made its appearance at Paris. The builder is Mr. Henri Barycki, of Warsaw, who has very skillfully utilized a few very curious mechanical principles in it.
The driver's seat is fixed in the interior of a wide ring to which are fastened the shafts. This ring revolves, by the aid of three pulleys or small wheels, within the large ring resting on the ground. It will be seen that when the horse is drawing the vehicle, the friction of this large wheel against the ground being greater than that of the concentric one within it, the latter will revolve until the center of gravity of the whole is situated anew in a line vertical to the point at which it bears on the ground. The result of such an arrangement is that the driver rolls on the large wheel just as he would do on the surface of an endless rail. As may be conceived, the tractive stress is, as a consequence, considerably diminished.
There are two side wheels which are connected by a flexible axle to the seat of the carriage, but these have no other purpose than that of preventing the affair from turning to one side or the other.
The "swallow," for so it is named, is made entirely of steel and wrought iron. It is very easily kept clean; the horse can be harnessed to it in three minutes; and, aside from its uses for pleasure, it is capable of being utilized in numerous ways.—La Nature.
[Our excellent contemporary, La Nature, is mistaken in its account of the above vehicle. It is an American invention and was first published, with engraving, in the SCIENTIFIC AMERICAN, December 16, 1882.]
* * * * *
BORING AN OIL WELL.
HOW THE HOLE WAS MADE AND THE OIL BROUGHT UP.
A letter from Bradford, Pa., says: The machinery used in boring one of these deep oil wells, while simple enough in itself, requires nice adjustment and skill in operating. First comes the derrick, sixty feet high, crowned by a massive pulley.
The derrick is a most essential part of the mechanism, and its shape and height are needed in handling the long rods, piping, casting, and other fittings which have to be inserted perpendicularly. The borer or drill used is not much different from the ordinary hand arm of the stone cutters, and the blade is exactly the same, but is of massive size, three or four inches across, about four feet long, and weighing 100 or 200 pounds. A long solid rod, some thirty feet long, three inches in diameter, and called the "stem," is screwed on the drill. This stem weighs almost a ton, and its weight is the hammer relied on for driving the drill through dirt and rock. Next come the "jars," two long loose links of hardened iron playing along each other about a foot.
The object of the jars is to raise the drill with a shock, so as to detach it when so tightly fixed that a steady pull would break the machinery. The upper part of the two jars is solidly welded to another long rod called the sinker bar, to the upper end of which, in turn, is attached the rope leading up to the derrick pulley, and thence to a stationary steam engine. In boring, the stem and drill are raised a foot or two, dropped, then raised with a shock by the jars, and the operation repeated.
If I may hazard a further illustration of the internal boring machinery of the well, let the reader link loosely together the thumbs and forefingers of his two hands, then bring his forearms into a straight line. Conceiving this line to be a perpendicular one, the point of one elbow would represent the drill blade, the adjacent forearm and hand the stem, the linked finger the jars, and the other hand and forearm the sinker bar, with the derrick cord attached at a point represented by the second elbow. By remembering the immense and concentrated weight of the upright drill and stem, the tremendous force of even a short fall may be conceived. The drill will bore many feet in a single day through solid rock, and a few hours sometimes suffices to force it fifty feet through dirt or gravel. When the debris accumulates too thickly around the drill, the latter is drawn up rapidly. The debris has previously been reduced to mud by keeping the drill surrounded by water. A sand pump, not unlike an ordinary syringe, is then let down, the mud sucked up, lifted, and then the drill sent down to begin its pounding anew. Great deftness and experience are needed to work the drill without breaking the jars or connected machinery, and, in case of accident, there are grapples, hooks, knives, and other devices without number, to be used in recovering lost drills, cutting the rope, and other emergencies, the briefest explanation of which would exceed the limits of this letter.
The exciting moment in boring a well is when a drill is penetrating the upper covering of sand rock which overlies the oil. The force with which the compressed gas and petroleum rushes upward almost surpasses belief. Drill, jars, and sinker bar are sometimes shot out along with debris, oil, and hissing gas. Sometimes this gas and oil take fire, and last summer one of the wells thus ignited burned so fiercely that a number of days elapsed before the flames could be extinguished. More often the tankage provided is insufficient, and thousands of barrels escape. Two or three years ago, at the height of the oil production of the Bradford region, 8,000 barrels a day were thus running to waste. But those halcyon days of Bradford have gone forever. Although nineteen-twentieths of the wells sunk in this region "struck" oil and flowed freely, most of them now flow sluggishly or have to be "pumped" two or three times a week.
"Piping" and "casing," terms substantially identical, and meaning the lining of the well with iron pipe several inches in the interior diameter, complete the labor of boring. The well, if a good flowing one, does all the rest of the work itself, forcing the fluid into the local tanks, whence it is distributed into the tanks of the pipe-line companies, and is carried from them to the refineries. The pipe lines now reach from the oil regions to the seaboard, carrying the petroleum over hill and valley, hundreds of miles to tide-water.
* * * * *
A CEMENT RESERVOIR.
The annexed figures represent, on a scale of 1 to 50, a plan and vertical section of a reservoir of beton, 11 cubic meters in capacity, designed for the storage of drinking water and for collecting the overflow of a canal. The volume of beton employed in its construction was 0.9 cubic meter per cubic meter of water to be stored. The inner walls were covered with a layer of cement to insure of tightness.
T is the inlet pipe, with a diameter of 0.08 m.
T' is the distributing pipe, and T" is the waste pipe.—Annales des Travaux Publics.
* * * * *
MACHINE FOR GRINDING LITHOGRAPHIC INKS AND COLORS.
The grinding of the inks and colors that are employed in lithographing is a long and delicate operation, which it has scarcely been possible up to the present time to perform satisfactorily otherwise than by hand, because of the perfect mixture that it is necessary to obtain in the materials employed.
Per contra, this manual work, while it has the advantage of giving a very homogeneous product, offers the inconvenience of taking a long time and being costly. The Alauzet machine, shown in the accompanying cut, is designed to perform this work mechanically.
The apparatus consists of a flat, cast iron, rectangular frame, resting upon a wooden base which forms a closet. In a longitudinal direction there is mounted on the machine a rectangular guide, along which travel two iron slides in the shape of a reversed U, which make part of two smaller carriers that are loaded with weights, and to which are fixed cast-steel mullers.
At the center of the frame there is fixed a support which carries a train of gear wheels which is set in motion by a pulley and belt. These wheels serve to communicate a backward and forward motion, longitudinally, to the mullers through the intermedium of a winch, and a backward and forward motion transversely to two granite tables on which is placed the ink or color to be ground. This last-named motion is effected by means of a bevel pinion which is keyed to the same axle as the large gear wheel, and which actuates a heart wheel—this latter being adjusted in a horizontal frame which is itself connected to the cast iron plate into which the tables are set.
This machine, which is 2 meters in length by 1 meter in width, requires a one-third horse power to actuate it. It weighs altogether about 800 kilogrammes.—Annales Industrielles.
* * * * *
A NEW EVAPORATING APPARATUS.
At a recent meeting of the Societe Industrielle of Elbeuf, Mr. L. Quidet described an apparatus that he had, with the aid of Mr. Perre, invented for evaporating juices.
In this new apparatus a happy application is made of those pipes with radiating disks that have for some time been advantageously employed for heating purposes. In addition to this it is so constructed as to give the best of results as regards evaporation, thanks to the lengthy travel that the current of steam makes in it.
It may be seen from an examination of the annexed cuts, the apparatus consists essentially of a cylindrical reservoir, in the interior of which revolves a system formed of seven pipes, with radiating disks, affixed to plate iron disks, EE. The reservoir is mounted upon a cast-iron frame, and is provided at its lower part with a cock, B, which permits of the liquid being drawn off when it has been sufficiently concentrated. It is surmounted with a cover, which is bolted to lateral flanges, so that the two parts as a whole constitute a complete cylinder. This shape, however, is not essential, and the inventors reserve the right of giving it the arrangement that may be best adapted to the application that is to be made of it.
In the center of the apparatus there is a conduit whose diameter is greater than that of the pipes provided with radiators, and which serves to cross-brace the two ends, EE, which latter consist of iron boxes cast in a piece with the hollow shaft of the rotary system.
The steam enters through the pipe, F, traverses the first evaporating pipe, then the second, then the third, and so on, and continues to circulate in this manner till it finally reaches the last one, which communicates with the exit, G.
Motion is transmitted to the evaporator by a gearing, H, which is keyed on the shaft, and is actuated by a pinion, L, connected with an intermediate shaft which is provided with fast and loose pulleys.
The apparatus is very efficient in its action, and this is due, in the first place, to the use of radiators, which greatly increase the heating surface, and second, to the motion communicated to the evaporating parts. In fact, each of the pipes, on issuing from the liquid to be concentrated, carries upon its entire surface a pellicle which evaporates immediately.
The arrangement devised by Messrs. Perre and Quidet realizes, then, the best theoretic conditions for this sort of work, to wit:
1. A large evaporating surface. 2. A very slight thickness of liquid. 3. A constant temperature of about from 100 deg. to 120 deg., according to the internal pressure of the steam.
Owing to such advantages, this apparatus will find an application in numerous industries, and will render them many services.—Revue Industrielle.
* * * * *
To the Editor of the Scientific American:
Your correspondent on this subject in the issue of April 14 cites an array of facts from which it would seem the proper conclusions should be inferred. I think the whole difficulty arises from a confusion of terms, and by this I mean a want of care to explain the unknown strictly in terms of the known; and I think underlying this error is a misconception as to what an animal is, and what animal strength is, only of course with reference to this particular discussion, i.e., in so far only as they may be considered physical organisms having no reference to the intellectual or moral development, all of which lies beyond the sphere of our discussion.
Purely with reference to the development of physical strength, which alone is under consideration, any animal organism whatsoever must be considered simply in the light of a machine.
A compound machine having two parts, first an arrangement of levers and points of application of power, all of which is purely mechanical, together with an arrangement of parts, designed, first, to convert fuel or food into heat, and, secondly, to transform heat into force, which is purely a chemical change in the first instance, and a transformation of energy in the second. So much for the animal—man or beast—as a machine physically considered.
What then is animal strength considered in the same light? The animal is not creative. It can make nothing—it can only transform. Does it create any strength or force? No. The strength it puts forth or exerts is merely the outcome of this transformation, which it is the office of the machine to perform.
What do we find transformed? Simply the energy, or potential, contained in the fuel or food we put into the machine. Its exact equivalent we find transformed to another form of energy, known as animal strength, which is simply heat within the system available for the working of its mechanical parts. How, then, is this energy which exists in the shape of animal strength used and distributed? This is the question the answer of which underlies this whole discussion as a principle. It is distributed to the different parts of the machine in proportion to the relative amount of physical work that nature has made it the office of any particular part to perform.
Let us see how it is with the bird machine. In course of flight he is called upon to remain in the air, which means that should he cease to make an effort to do this, i.e., should he cease to expend energy in doing it, he would fall during the first second of time after ceasing to make the effort some sixteen feet toward the center of the earth. But he remains in the air for hours and days at a time. What is he, then, doing every second of that time? He is overcoming the force of gravitation, which is incessantly pulling him down. That is, every second he is doing an amount of work equal to his weight—say 10 lb. multiplied by 16—say 160 lb. approximately; all this by beating the air with his wings. Now let us institute a slight comparison—and the work shall be performed by a man, who climbs a mountain 10,000 feet high in 10 hours. The man weighs 150 lb.; he climbs 10,000 feet; 1,500,000 foot pounds is, then, the work done. He does it in 10 hours, or 36,000 seconds, which gives an amount of work of only 42 foot pounds per second performed by his muscles of locomotion.
At the end of the ten hours the man is exhausted, while the bird delights in further flight. To what is this difference of condition due? It is due simply to the difference in the machine; but this, you say, is not explaining the unknown in terms of the known. Let us see, then, if we cannot do this. In the two accounts of work done as above cited in the case of the man and the bird, an amount of energy, i.e., heat of the system, has been expended just proportional to the work done.
Now while the bird has expended more energy in this particular work of locomotion than has the man, we find the bird machine has done little else; he has consumed but little of his available heat force in exercising his brain or the other functions of his system, or in preserving the temperature of the body, and but little of his animal heat, which is his strength, has been radiated into space. In short, we find the bird machine so devised by nature that a very large proportion of the available energy of the system can be used in working those parts contrived for locomotion, and resist the force of gravity, or, what is the same thing, nature has placed a greater relative portion of the whole furnace at the disposal of these parts than she has in man. The breast muscles of the bird are so constructed as to burn a far greater proportional amount of the fuel from which all energy is derived than do the muscles of the rest of the body combined.
Let us see how it is with the man who has climbed the mountain. In this machine we find affairs in a very different state. During his climbing he has been doing a vast amount of other work, both internal and external. His arms, his whole muscular system, in fact, has been vigorously at work, all drawing upon his total available energy. His brain has been in constant and unremitted action, as well as the other internal organs, which require a greater proportional amount of energy than they did in the bird. Besides this, he has been radiating his animal heat into space in a far greater amount. All these parts must be supplied; they cannot be neglected while the accumulated surplus is given to the machinery for locomotion or lifting. This then is what constitutes what I call the difference in the machine, which is purely one of organic development depending upon the functions nature has determined that the different organs shall perform. As for the pterodactyl quoted in the last article, I have only to remark that this discussion arose purely from a consideration of what was the best type of flying apparatus nature had given man to study, and I claim that this prehistoric bird of geology does not come within this class. For if it is not fully established that this species had become extinct long before the appearance of man on the globe, it is at least certain that the man of that early day had not dreamt of flying and was presumably content if he could find other means to evade the pterodactyl's claw.
F.J.P., U.S. Army.
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THE PORTRUSH ELECTRIC RAILWAY, IRELAND.
[Footnote 1: A paper recently read before the Society of Arts, London.]
By DR. EDWARD HOPKINSON.
In the summer of 1881, Mr. W.A. Traill, late of H.M. Geological Survey, suggested to Dr. Siemens that the line between Portrush and Bushmills, for which Parliamentary powers had been obtained, would be suitable in many respects for electrical working, especially as there was abundant water power available in the neighborhood. Dr. Siemens at once joined in the undertaking, which has been carried out under his direction. The line extends from Portrush, the terminus of the Belfast and Northern Counties Railway, to Bushmills in the Bush valley, a distance of six miles. For about half a mile the line passes down the principal street of Portrush, and has an extension along the Northern Counties Railway to the harbor. For the rest of the distance, the rails are laid on the sea side of the county road, and the head of the rails being level with the ground, a footpath is formed the whole distance, separated from the road by a curbstone. The line is single, and has a gauge of three feet, the standard of the existing narrow gauge lines in Ulster. The gradients are exceedingly heavy, as will be seen from the diagram, being in parts as steep as 1 in 35. The curves are also in many cases very sharp, having necessarily to follow the existing road. There are five passing places, in addition to the sidings at the termini and at the carriage depot. At the Bushmills end, the line is laid for about 200 yards along the street, and ends in the marketplace of the town. It is intended to connect it with an electrical railway from Dervock, for which Parliamentary powers have already been obtained, thus completing the connection with the narrow gauge system from Ballymena to Larne and Cushendall. About 1,500 yards from the end of the line, there is a waterfall on the river Bush, with an available head of 24 feet, and an abundant supply of water at all seasons of the year. Turbines are now being erected, and the necessary works executed for employing the fall for working the generating dynamo machines, and the current will be conveyed by means of an underground cable to the end of the line. Of the application of the water power it is unnecessary to speak further, as the works are not yet completed. For the present, the line is worked by a small steam-engine placed at the carriage depot at the Portrush end. The whole of the constructive works have been designed and carried out by Mr. Traill, assisted by Mr. E.B. Price.
The system employed may be described as that of the separate conductor. A rail of T-iron, weighing 19 pounds to the yard, is carried on wooden posts, boiled in pitch, and placed ten feet apart, at a distance of 22 inches from the inside rail and 17 inches above the ground. This rail comes close up against the fence on the side of the road, thus forming an additional protection. The conductor is connected by an underground cable to a single shunt-wound dynamo machine, placed in the engine shed, and worked by a small agricultural steam engine of about 25 indicated horse power. The current is conveyed from the conductor by means of two springs, made of steel, rigidly held by two steel bars placed one at each end of the car, and projecting about six inches from the side. Since the conducting rail is iron, while the brushes are steel, the wear of the latter is exceedingly small. In dry weather they require the rail to be slightly lubricated; in wet weather the water on the surface of the iron provides all the lubrication required. The double brushes, placed at the extremities of the car, enable it to bridge over the numerous gaps, which necessarily interrupt the conductor to allow cart ways into the fields and commons adjoining the shore. On the diagram the car is shown passing one of these gaps: the front brush has broken contact, but since the back brush is still touching the rail, the current has not been broken. Before the back brush leaves the conductor, the front brush will have again risen upon it, so that the current is never interrupted. There are two or three gaps too broad to be bridged in this way. In these cases the driver will break the current before reaching the gap, the momentum of the car carrying it the 10 or 12 yards it must travel without power.
The current is conveyed under the gaps by means of an insulated copper cable carried in wrought-iron pipes, placed at a depth of 18 inches. At the passing places, which are situated on inclines, the conductor takes the inside, and the car ascending the hill also runs on the inside, while the car descending the hill proceeds by gravity on the outside lines.
From the brushes the current is taken to a commutator worked by a lever, which switches resistance frames placed under the car, in or out, as may be desired. The same lever alters the position of the brushes on the commutator of the dynamo machine, reversing the direction of rotation, in the manner shown by the electrical hoist. The current is not, as it were, turned full on suddenly, but passes through the resistances, which are afterward cut out in part or altogether, according as the driver desires to run at part speed or full speed.
From the dynamo the current is conveyed through the axle boxes to the axles, thence to the tires of the wheels, and finally back by the rails, which are uninsulated, to the generating machine. The conductor is laid in lengths of about 21 feet, the lengths being connected by fish plates and also by a double copper loop securely soldered to the iron. It is also necessary that the rails of the permanent way should be connected in a similar manner, as the ordinary fish plates give a very uncertain electrical contact, and the earth for large currents is altogether untrustworthy as a conductor, though no doubt materially reducing the total resistance of the circuit.
The dynamo is placed in the center of the car, beneath the floor, and through intermediate spur gear drives by a steel chain on to one axle only. The reversing levers, and also the levers working the mechanical brakes, are connected to both ends of the car, so that the driver can always stand at the front and have uninterrupted view of the rails, which is of course essential in the case of a line laid by the side of the public road.
The cars are first and third class, some open and some covered, and are constructed to hold twenty people, exclusive of the driver. At present, only one is fitted with a dynamo, but four more machines are now being constructed by Messrs. Siemens Bros., so that before the beginning of the heavy summer traffic five cars will be ready; and since two of these will be fitted with machines capable of drawing a second car, there will be an available rolling stock of seven cars. It is not intended at present to work electrically the portion of the line in the town at Portrush, though this will probably be done hereafter; and a portion, at least, of the mineral traffic will be left for the two steam-tramway engines which were obtained for the temporary working of the line pending the completion of the electrical arrangements.
Let us now put in a form suitable for calculation the principles with which Mr. Siemens has illustrated in a graphic form more convenient for the purposes of explanation, and then show how these principles have been applied in the present case.
Let L be the couple, measured in foot-pounds, which the dynamo must exert in order to drive the car, and w the necessary angular velocity. Taking the tare of the car as 50 cwt., including the weight of the machinery it carries, and a load of twenty people as 30 cwt., we have a gross weight of 4 tons. Assume that the maximum required is that the car should carry this load at a speed of seven miles an hour, on an incline of 1 in 40. The resistance due to gravity may be taken as 56 lb. per ton, and the frictional resistance and that due to other causes, say, 14 lb. per ton, giving a total resistance of 280 lb., at a radius of 14 inches. The angular velocity of the axle corresponding to a speed of seven miles an hour, is 84 revolutions per minute. Hence L = 327 foot pounds, and w = (2[pi] x 84) / 60.
If the dynamo be wound directly on the axle, it must be designed to exert the couple, L, corresponding to the maximum load, when revolving at an angular velocity, w, the difference of potential between the terminals being the available E.M.F. of the conductor, and the current the maximum the armature will safely stand. This will be the case in the Charing-cross Electrical Railway. But when the dynamo is connected by intermediate gear to the driving wheels only, the product of L and w remains constant, and the two factors may be varied. In the present case L is diminished in the ratio of 7 to 1, and w consequently increased in the same ratio. Hence the dynamo, with its maximum load, must revolve at 588 revolutions per minute, and exert a couple of forty-seven foot-pounds. Let E be the potential of the conductor from which the current is drawn, measured in volts, C the current in amperes, and E1 the E.M.F. of the dynamo. Then E1 is proportional to the product of the angular velocity, and a certain function of the current. For a velocity [omega], let this function be denoted by f(C). If the characteristic of the dynamo can be drawn, then f(C) is known.
We have then
w E1 = ———— f [Omega] (1.)
If R be the resistance in circuit by Ohm's law,
E - E1 C = ———— R
w = E ———- f(C) [Omega] ———————— R
[Omega](E - CR) (2.) w = ————————- f(C)
Let a be the efficiency with which the motor transforms electrical into mechanical energy, then—
Power required = L w = a E1 C
w = a C ———- f(C) [Omega]
Dividing by w,
a C f(C) L = ———— . (3.) [Omega]
It must be noted that L is here measured in electrical measure, or, adopting the unit given by Dr. Siemens in the British Association Address, in joules. One joule equals approximately 0.74 foot pound. Equation 3 gives at once an analytical proof of the second principle stated above, that for a given motor the current depends upon the couple, and upon it alone. Equation 2 shows that with a given load the speed depends upon E, the electromotive force of the main, and R the resistance in circuit. It shows also the effect of putting into the circuit the resistance frames placed beneath the car. If R be increased, until CR is equal to E, then w vanishes, and the car remains at rest. If R be still further increased, Ohm's law applies, and the current diminishes. Hence suitable resistances are, first, a high resistance for diminishing the current, and consequently, the sparking at making and breaking of of the circuit; and, secondly, one or more low resistances for varying the speed of the car. If the form of f(C) be known, as is the case with a Siemens machine, equations 2 and 3 can be completely solved for w and C, giving the current and speed in terms of L, E, and R. The expressions so obtained are not without interest, and agree with the results of experiment.
It may be observed that an arc light presents the converse case to a motor. The E.M.F. of the arc is approximately constant, whatever the intensity of the current passing between the carbons; and the current depends entirely on the resistance in circuit. Hence the instability of an arc produced by machines of low internal resistance, unless compensated by considerable resistance in the leads.
The following experiment shows in a striking form the principles just considered: An Edison lamp is placed in parallel circuit with a small dynamo machine, used as a motor. The Prony brake on the pulley of the dynamo is quite slack, allowing it to revolve freely. Now let the lamp and dynamo be coupled to the generator running at full speed. First, the lamp glows, in a moment it again becomes dark, then, as the dynamo gets up speed, glows again. If the brake be screwed up tight, the lamp once more becomes dark. The explanation is simple. Owing to the coefficient of self-induction of the dynamo machine being considerable, it takes a finite time for the current to obtain an appreciable intensity, but the lamp having no self-induction, the current at once passes through it, and causes it to glow. Secondly, the electrical inertia of the dynamo being overcome, it must draw a large current to produce the kinetic energy of rotation, i.e., to overcome its mechanical inertia; the lamp is therefore practically short-circuited, and ceases to glow. When once the rotation has been established, the current through the dynamo becomes very small, having no work to do except to overcome the friction of the bearings, hence the lamp again glows. Finally, by screwing up the brake, the current through the dynamo is increased, and the lamp again short-circuited.
It has often been pointed out that reversal of the motor on the car would be a most effective brake. This is certainly true; but, at the same time, it is a brake that should not be used except in cases of emergency. For this reason, the dynamo revolving at a high speed, the momentum of the current is very considerable; hence, owing to the self-induction of the machine, a sudden reversal will tend to break down the insulation at any weak point of the machine. The action is analogous to the spark produced by a Ruhmkorff coil. This was illustrated at Portrush; when the car was running perhaps fifteen miles an hour, the current was suddenly reversed. The car came to a standstill in little more than its own length, but at the expense of breaking down the insulation of one of the wires of the magnet coils. The way out of the difficulty is evidently at the moment of reversal to insert a high resistance to diminish the momentum of the current.
In determining the proper dimensions of a conductor for railway purposes, Sir William Thomson's law should properly apply. But on a line where the gradients and traffic are very irregular, it is difficult to estimate the average current, and the desirability of having the rail mechanically strong, and of such low resistance that the potential shall not vary very materially throughout its length, becomes more important than the economic considerations involved in Sir William Thomson's law. At Portrush the resistance of a mile, including the return by earth and the ground rails, is actually about 0.23 ohm. If calculated from the section of the iron, it would be 0.15 ohm, the difference being accounted for by the resistance of the copper loops, and occasional imperfect contacts. The E.M.F. at which the conductor is maintained is about 225 volts, which is well within the limit of perfect safety assigned by Sir William Thomson and Dr. Siemens. At the same time the shock received by touching the iron is sufficient to be unpleasant, and hence is some protection against the conductor being tampered with.
Consider a car requiring a given constant current; evidently the maximum loss due to resistance will occur when the car is at the middle point of the line, and will then be one-fourth of the total resistance of the line, provided the two extremities are maintained by the generators at the same potential. Again, by integration, the mean resistance can be shown to be one-sixth of the resistance of the line. Applying these figures, and assuming four cars are running, requiring 4 horse power each, the loss due to resistance does not exceed 4 per cent. of the power developed on the cars; or if one car only be running, the loss is less than 1 per cent. But in actual practice at Portrush even these estimates are too high, as the generators are placed at the bottom of the hills, and the middle portion of the line is more or less level, hence the minimum current is required when the resistance is at its maximum value.
The insulation of the conductor has been a matter of considerable difficulty, chiefly on account of the moistness of the climate. An insulation has now, however, been obtained of from 500 to 1,000 ohms per mile, according to the state of the weather, by placing a cap of insulite between the wooden posts and T-iron. Hence the total leakage cannot exceed 2.5 amperes, representing a loss of three-fourths of a horse power, or under 5 per cent, when four cars are running. But apart from these figures, we have materials for an actual comparison of the cost of working the line by electricity and steam. The steam tramway engines, temporarily employed at Portrush, are made by Messrs. Wilkinson, of Wigan, and are generally considered as satisfactory as any of the various tramway engines. They have a pair of vertical cylinders, 8 inches diameter and one foot stroke, and work at a boiler pressure of 120 lb., the total weight of the engine being 7 tons. The electrical car with which the comparison is made has a dynamo weighing 13 cwt., and the tare of the car is 52 cwt. The steam-engines are capable of drawing a total load of about 12 tons up the hill, excluding the weight of the engine; the dynamo over six tons, including its own weight; hence, weight for weight, the dynamo will draw five times as much as the steam-engine. Finally, compare the following estimates of cost. From actual experience, the steam-engine, taking an average over a week, costs—
L s. d. Driver's wages. 1 10 0 Cleaner's " 0 12 0 Coke, 581/2 cwt. at 25s. per ton. 3 13 11/2 Oil, 1 gallon at 3s. 1d. 0 3 1 Tallow, 4 lb. at 6d. 0 2 0 Waste, 8 lb. at 2d. 0 1 4 Depreciation, 15 per cent. on L750. 2 3 3 ————— Total. L8 4 91/2
The distance run was 312 miles. Also, from actual experience, the electrical car, drawing a second behind it, and hence providing for the same number of passengers, consumed 18 lb. of coke per mile run. Hence, calculating the cost in the same way, for a distance run of 312 miles in a week—
L s. d. Wages of stoker of stationary engine. 1 0 0 Coke, 52 cwt. at 25s. per ton. 2 15 0 Oil, 1 gallon at 3s. 1d. 0 3 1 Waste, 4 lb. at 2d. 0 0 8 Depreciation on stationary engine, 10 per cent. } on L300 11s. 6d. } Depreciation of electrical apparatus, 15 per cent. } 2 0 4 on L500, L1 8s. 10d. } ————- Total. L5 19 1
A saving of over 25 per cent.
The total mileage run is very small, on account of the light traffic early in the year. Heavier traffic will tell very much in favor of the electric car, as the loss due to leakage will be a much smaller proportion of the total power developed.
It will be observed that the cost of the tramway engines is very much in excess of what is usual on other lines, but this is entirely accounted for by the high price of coke, and the exceedingly difficult nature of the line to work, on account of the curves and gradients. These causes send up the cost of electrical working in the same ratio, hence the comparison is valid as between the steam and electricity, but it would be unsafe to compare the cost of either with horse-traction or wire-rope traction on other lines. The same fuel was burnt in the stationary steam-engine and in the tramway engines, and the same rolling stock used in both cases; but, otherwise, the comparison was made under circumstances in favor of the tramway engine, as the stationary steam-engine is by no means economical, consuming at least 5 lb. of coke per horse-power hour, and the experiments were made, in the case of the electrical car, over a length of line three miles long, which included the worst hills and curves, and one-half of the conductor was not provided with the insulite caps, the leakage consequently being considerably larger than it will be eventually.
Finally, as regards the speed of the electrical car, it is capable of running on the level at the rate of 12 miles per hour, but as the line is technically a tramway, the Board of Trade Regulations do not allow the speed to exceed 10 miles an hour.
Taking these data as to cost, and remembering how this will be reduced when the water power is made available, and remembering such considerations as the freedom from smoke and steam, the diminished wear and tear of the permanent way, and the advantage of having each car independent, it may be said that there is a future for electrical railways.
We must not conclude without expressing our best thanks to Messrs. Siemens Bros. for having kindly placed all this apparatus at our disposal to-night, and allowing us to publish the results of experiments made at their works.
* * * * *
THE THOMSON-HOUSTON ELECTRIC LIGHTING SYSTEM.
The generator is known as the "Thomson spherical," on account of the nearly spherical form of its armature, and differs radically from all others in all essential portions, viz., its field magnets, armature, and winding thereof, and in its commutator; both in principle and construction, and, besides, it is provided with an automatic regulator, an attachment not applied to other generators. The annexed view of the complete machine will convey an idea of the general appearance and disposition of its parts.
The revolving armature which generates the electrical current is made internally of a hollow shell of soft iron secured to the central portion of the shaft between the bearings, and is wound externally with a copper conducting wire, constituting three coils or helices surrounding the armature, which coils are, however, permanently joined, and in reality act as a single three-branched wire.
This wire, being wound on the exterior of the armature, is fully exposed to the powerful magnetic influence of the field poles, which inclose the armature almost completely. The armature will thus be seen to be thoroughly incased and protected, at the same time that all the wire upon it is subject to a powerful action of the surrounding magnets, resulting in an economy in the generation of current in its coils. The form of the armature being spherical, very little power is lost by air friction, and no injury can occur from increased speed developing centrifugal force. The field magnets, which surround the armature, are cast iron shells, wound outside with many convolutions of insulated copper wire, and are joined externally by iron bars to convey the magnetism. These outer bars serve also as a most efficient protection to the wire and armature of the machine during transportation or otherwise. Objects cannot fall upon or rest upon the wire coils and injure them. The coils of wire upon the field magnets surround not only the iron poles or shells, but are situated also so as to surround likewise the revolving armature, and increase the effect produced in it by direct induction and magnetism. This feature is not used in any other generator, nor does any other make use of a spherical armature. The shaft is mounted in babbitted bearings of ample size, sustained by a handsome frame therefor, and is of steel, finely turned and perfectly true. The shaft and armature together are balanced with the utmost care, and run without buzz or rumble. The armature wire is kept cool by an active circulation of air over its whole surface during revolution. The commutator, or portion from which the currents developed in the armature are carried out for use, is a beautiful piece of mechanism. It is mounted upon the end of the shaft, and has attached to it the wires, three only, coming from the armature wire through the tubular shaft.
The commutator is peculiar, consisting of only three segments of a copper ring, while in the simplest of other continuous current generators several times that number exist, and frequently 120! segments are to be found. These three segments are made so as to be removable in a moment for cleaning or replacement. They are mounted upon a metal support, and are surrounded on all sides by a free air space, and cannot, therefore, lose their insulated condition. This feature of air insulation is peculiar to this system, and is very important as a factor in the durability of the commutator. Besides this, the commutator is sustained by supports carried in flanges upon the shaft, which flanges, as an additional safeguard, are coated all over with hard rubber, one of the finest known insulators. It may be stated, without fear of contradiction, that no other commutator made is so thoroughly insulated and protected. The three commutator segments virtually constitute a single copper ring, mounted in free air, and cut into three equal pieces by slots across its face. Four slit copper springs, called commutator brushes or collectors, are allowed to bear lightly upon the commutator when it revolves, and serve to take up the current and convey it to the circuit. These commutator brushes are carried by movable supports, and their position is automatically regulated so as to control the strength of the developed current—a feature not found in other systems. This feature, as well as the fact that the commutator can be oiled to prevent wear, saves attendance and greatly increases the durability of the wearing surfaces, while the commutator brushes are maintained in the position of best adjustment. The commutator and brushes, in consequence, after weeks of running, show scarcely any wear.
THE AUTOMATIC CURRENT REGULATOR.
This consists of a peculiar magnet attached to the frame of the generator, and the movable armature of which has connections to the supports of the commutator brushes for controlling their position. The regulator magnet is so formed as to give a uniform attraction upon its armature in different positions. In Thomson's improved form this is accomplished in a novel manner by making the pole of the magnet paraboloidal in form, and making an opening in the movable armature to encircle said pole.
The armature is hung on pivots so as to be free to move only toward and from the regulating magnet on changes in the current traversing the latter, and being connected to the commutator brushes, automatically adjusts their position. By this means the power of the generator is adapted to run any number of lights within its limit of capacity, or may be short circuited purposely or by accident without difficulty arising therefrom; and a number of instances have occurred where the injurious effects of a short circuit accidentally formed have been entirely obviated by the presence of the regulator. In one instance four generators, in series representing over forty lights' capacity, were accidentally short circuited, and no injury or even noticeable action took place except a quick movement of the regulators in adapting themselves to the new conditions. Had this accident occurred to generators unprovided with regulators, great injury or possible destruction of the apparatus would have resulted. It is important to a full understanding of the regulation, to state that its action is independent of resistances introduced, that it saves power and carbons in proportion to lights extinguished, and that it compensates for speed variations above the minimum speed. The manner of its action is to control the generation of current at the source in the armature, and it does so by combining certain electrical actions so as to obtain a differential effect, such that when small force of current only is required it alone is furnished, and when the maximum force is needed the same shall be forthcoming.
On the larger generators we combine with the regulator magnet above described an exceedingly sensitive controller magnet governing the regulation, and by whose accuracy the smallest variations of current are counteracted, and the operation of the generator rendered perfect. The controller magnet is contained in a box placed on the wall or other support near the generator, and consists of a delicate double axial magnet controlling the admission of current to the regulator, upon the generator, and its action is exceedingly simple and effective. So perfect is the action that in a circuit of twenty-five to thirty lights, lights may be removed or put out in rapid succession without apparently affecting those that remain. Besides, we have been enabled to put out even eight or ten lights together instantly, while the remainder burn as before. The features above set forth are peculiar to the Thomson-Houston system, and have been thoroughly covered by patents, and cannot therefore be adopted into other systems.