JULY I 2, 1901.] DIE FORGING. No. V.

By JosEPH Ho:n.NER. HAVING a power hammer at command, the smith

often adopts different methods of formation from those which he would choose if working on the an,il. This is seen strikingly in the forked and the flan~ed types ?f ends, in which a large amount of draw1ng down IS done by the power hammer in preference to welding small to large sections. A study of these will afford a proper sequel to our study of bossed ends, which have some features 1n common.

The case of forked t:'nds, which are so numerous in engineers' work, often calls for settlement between the smithy and the machine shop. The sm~th wou~d generally wish to forge these ends sohd, leavmg the forks to be slotted or milled.

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E N G I N E E R I N G. disposition of fibre, the liability of the fork to open and to crack at a would be much increased, and th1s would certainly happen with inferior spilly iron. Clearly, too, the wider the fork, the more is such a risk increased, because a wide root presents a. larger section of short fibre to the risk of cracking. And this is another reason why, apart from questions of facilities for machining from the solid, it is better to form iron forks by bending, than by forging them solid. With the best qualities of iron the difference is of less importance, though it always exists, and in steel it may be quite neglected. With this material the question is almost wholly that of convenience of manufacture in smithy and in machine shop, between which an economical balance must be struck.

In this class of work we have three broad

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37 The difference in these dies is in the line of jointure which in this particular instance may be made in either direction ; since the formative action and the delivery of the forging are facilitated in about equal degrees in each instance, perpendicular faces and curved outlines being about equally averaged. In each case a preliminary pair of dies can be used of similar form, but ! in. or t in. larger in one or both directions for roughing the fullered ends into a form more nearly like that to be imparted in these finishing dies.

The forked end shown in Figs. 97 and 98 is finished in the single die in Figs. 105 and 106. The piercing of the block with a hole at A is done sometimes, in order that if the forging becomes fast in the block, the latter can be turned over, and the forging knocked out by a blow delivered through the hole. The risk of the

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The machine shop manager will often prefer to clean them up only, by milling, filing, or grinding, according to the class of work demanded in any given case, and the machines available. Formerly these alternatives were of greater importance than they are now, in those shops at least which are equipped with modern tools- as a result of the greater stiffness and power of these tools by corn-parison with their predecessors. Generally the question is settled in this way: Small rods have their ends left solid, large ones with wide ends have their forgings made forked. In some respects the latter are better, because t he fibre follows the fork, but this applies more especially to iron rather than to steel, and is therefore a question of less importance than it was 10 or 15 years ago, before steel came into such common use in the smithy.

Figs. 97 and 98 illustrate points that must be borne in mind when forging forked ends in iron. In Fig. 97 the fibre must run in the plane of the paper- appearing edgewise in Fig. 98. I t is clear t hat if the bar were selected with the opposite

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the fibre, a round hole is first punched at the bottom of the intended division, and the sett worked down into that, cubting alternately from both sides of the bar. Fig. 107 illustrates the first stage, following any drawing down which may have been done for the web. The punch is being driven into the bar A, which is supported on a ring B on the anvil of the hammer. It is driven in from both sides alter-nately, the hole, slightly tapered, meeting in the middle of the bar. The action is only slightly punching or detrusive, but consists chiefly in a squeezing of the metal out sideways. Though fibres are divided, yet they are also squeezed and consolidated. And there is the resulting dif-ference between leaving a radius, and the keen angle, which the sett, if used at first, and alone, would produce. This is a little detail of much importance, and one that has many appli-cations in forged work, as in the convexity im-parted to the edges of fullering tools, and in a slight degree on the edges of .flatters, by which when working against a shoulder a slight radius or hollow is left ; and which is nearly as important in forgings as in castings.

The sett is seen beginning its work in Figs. 108 and 109, in front and in side elevations. This cuts half way through from each side, the division meet-ing in the middle of the bar, the appearance of which, when divided, is illustrated in Fig. 110. Afterwards the end is laid across the anvil, and the forks hammered out with a hand hammer until they are opened out about as far as is shown in Fig. 111 ; and then the precise shape of the fork is imparted over a former, A, Fig. 112, which is an inch or so wider than the fork. The setting down on this is done with hand hammers, the work being commonly transferred to the anvil into the hole in which the square shank of the former drops. But if the forked end is made as a short piece, to be welded subsequently to the web, the former can be used under the power hammer, the pressure of the tup being utilised to hold the work down on the anvil block, while setting over is done with hand hammers. Afterwards the fork, enclosing the former, can be laid flatwise on the anvil, and its faces corrected in two or three blows of the tup.

Figs. 113 and 114 illustrate another way in which broad iorked ends are roughed out, though it is not so suitable for deep as for shallow forks. A gouge sett, handled with an iron rod, is driven into the bar from each side, cutting very closely to the finished sizes. The waste piece is severed by turn-ing the gouge round to the sides, or by cutting down these with the chisel sett, the result being that the interior of the fork is brought nearly to size without any stress being put upon the metal. This should be done before the outer portions are roughed out, so retaining the mass of metal behind to resist the pressure of the sett.

If a forked end is of moderate thickness only, the space can . be punc~ed out by. arrangeme~ts illustrated prevwusly, without stressmg or opening out the fibre. If a forked end is opened out by punching, it is better if done gradually, in two or three operations. Dies may be used for these, and the process carried through gradually. At the same time the metal at the bottom of the fork will be consolidated by pressure in the dies. As in the previous example, there is the advantage that the shape of the roug~ed-out end is . nearly correct; while when a fork IS opened out with the hot sett, it has to be shaped over the anvil or on a block, and finished on a former of the exact shape of the inside of the fork. But the results are more satisfactory in iron, bee~ use there are no short fibres at the root, their direction corresponding exactly with the curves of the forks.

E N G I N E E R I N G . The finish of plain ends, the forgings of which

are forked but not bossed, is not always imparted in dies unless a large quantity is required. For instance, in Fig. 112 the former A imparts the only important shape, and is in strictness a die, only it does not embrace the whole of the end. But the webs et a of the fork correspond in this case with the width of the original bar, and the only portion for which dies would be helpful are the shoulders b and the ends c. Now b is practically formed by the bending round and setting 1ound the former. This is not a case like those in Figs. 101 to 106, in which the curves ~re roughed out with fullers, assisted sometimes with the hot gouge sett, and for the cheap finishing of the curves of which dies are essential. With regard to the ends c c in Fig. 112, as these are simply half round they can be out with a gouge sett on the former- laid fiatwise, and finished with a hollow tool. Small ends forged with forks are properly finished in dies like Figs. 115 and 116. Large ends having bosses like Figs. 117 and 118, must be finished in similar dies if the bosses are to be shaped decently and cheaply, the dies having the same general construction as those shown in Figs. 115 and 116.

Take, last1y, the levers and arms in Figs. 119 and 120 ; it would be poor practice to attempt to slot out these from solid ends. At first sight it might appear as though these ends might have their spaces punched out; but that is not a suitable method either, because the disproportion between the area punched and the metal left is so great that the latter would be distressed. Also it would, if done in iron, leave a quantity of short fibre in the necks. The proper way to form these is by opening out and setting round. Thus, without giving a separate figure for every minute detail, this lever, if, say, of 12 in. to 18 in. in length, would be made without welding, by taking a bar having a cross-section a trifle over double that of the cross-section of metal conta.ined in the larger forked end of the two. Two holes are then punched with a punch at the roots of the forks, as seen in Fig. 121, and the metal is divided with a hot sett from these holes to the ends. Afterwards the fork can be opened out, without risk of cracks occurring in the root of the curve. The stem or web is next drawn down about the central portions as indicated by the dotted lines, the short length of metal at a , et being swaged down, and extended into the long web, in Figs. 119 and 120. The bosses have still to be dealt with. These may be finished singly in separate dies before the forks are bent right round, being set at an angle of 45 deg. with the stem. Or it is prac-ticable to form both bosses of one end in a single pair of dies of similar construction to Figs. 115 and 116 ; but the forging must be brought nearly to dimensions, either by swaging down by band or else in a pair of roughing dies of larger dimen-sions, across the web sect.ion, and smaller across the bosses, to effect a gradual formation. If the lever is over about 10 in. or 12 in. in length, it is better to make each end separately, and weld the stem in the centre, otherwise the dies would be heavy to handle, and the forks would bind in them also. In welding up, measurement between centres has to be carefully made, and a probable twist in the ends to be taken out subsequently, remarks on which kind of work will follow in due course.

If, when opening out a fork, the ~etal becomes cracked it is necessary to take a weldmg heat over the part and consolidate it either by hand or in dies.

The s~bsequent treatment of forked ends v~ries much with their particular shapes and proport10ns. There are three specific cases : one that in which the ends are not swelled out into bosses larger than the portions to the rear, an ex~mple of which is seen in Fig. 112. These are stmple, because t~e width of the bar is left the same after as before It was forked and all that remains is to bend it into the forked for:n. But in most instances the ends are bossed larger than the web lying immediately in. the rear. Then the bosses may be of the same thick-ness through as the webs, which simplifies the work or they may haYe boss facing& on one or on both faces. Then there is more than one alterna-tive of manufacture .

The governor arm in Figs. 122 and 123 can be made either by welding or in the solid. If in the solid, the work will be started from the ball end, and all the rest swaged down therefrom, the details of w hi eh will be apparent from the previous descriptions. The forging should be fully finished entirely in one die. Figs. 124 and 125 furnish an example of a similar kind, also finished entirely in one die, drawings of which would be mainly a repe-tition of examples previously given.

The question of finishing ends is largely one of the degree of accuracy demanded and of the number wanted off, and to some extent also of the propor-tion of parts. When forks are set o.ver a. former, the smith may or may not have a gu1de for exact adjustment of the lengths of the forks. When a narrow fork is bent, its webs are generally set over and round by the assistance only of the eye of the workman, any slight inaccuracy is corrected by subsequent trimming, or by machining. Some large forks are set by the aid of a bending b~ock, ~n which they are cottered. When forks terminate In bossed ends, like the last examples given, a slight want of symmetry in bending is sufficient to throw the centres out of uniformity, so that they will not

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[ J ULY I 2, 1901.

hold up for tooling or grinding. Then there is an advantage in finishing both the ends at once in dies. It is less easy to finish forked ends in dies when the ends are wide in the gap and deep also, than when they are narrow and shallow, because the inside faces, as they cool, bind against the faces of the dies, and become tight. It is therefore necessary in deep ends to impart a considerable taper to the inner faces, and also to get through the stamping and get the forging out as quickly as possible. The governor levers in Figs. 122 to 125 are favourably shaped in this respect, being, though broad, very shallow, so that they can be released readily.

THE INSTITUTION OF ELEOTRICAL ENGINEERS IN GERMANY.

(Continued from page 12.) WEDNESDAY, June 26, was the second day of the

Allgemeine Elektricitats Gesellschaft, and Thurs-day morning falling again to Siemens and Halske, the two firms each entertained their visitors for the same period of one day and a half. Of the three large electrical firms of Berlin, those of Messrs. Siemens and Halske, the Union, and the Allgemeine Elektrioitats -Gesellschaft (the last-named, the A. E. G.), had at its start neither the lustre of a great name like Siemens, nor the power-ful aid of a parent company like the Thomson-Houston. The A. E. G. has had to fight for a posi-tion with rivals already well entrenched in the field. We are not wrong, we believe, in stating that many electricians think the director - general of the A. E. G., Mr. Emil Ra.thenau, is the soul of the company. His eo-directors are Messrs. Felix Deutsch, R. Kolle, P. Jordan, P. Mamroth, Dr. W. Rathenau-esssntially as a man of great orga-pising and financial capacity. He is, as a matter oi fact, also an engineer of distinction, of whose ability and indefatigable activity all the members of the staff speak in the highest terms. Many men have, of course, contributed to the success of the firm. We need only mention the name Dolivo-Dobrowolsky, who certainly worked out the tri-phase motor, though Ferraris and Tesla and others may have prior claims in the theoretical field. It is curious to note that the late Professor Ferraris thought chiefly of triphase instruments. Practice took up the triphase motor with enthusiasm, and recently only triphase meters havecome to the front . Returned from the Electrical Exhibition at Paris of 1881, Mr. Rathenau acquired the German patent rights of the Compagnie Continenta.le Edison, and soon induced several bankers to establish a so-called "study " company, which was t urned into the German Edison Company, but which broke the connection with the parent company in 1887, and then assumed the present name. The first object of the study company had been the foundation of an electric central station. A small installat.ion in a printing business having proved a success, the Union Club was lighted by electricity, and this plant became the nucleus of the first A. E. G. power station. At present the firm employs in its various works about 17,300 men (not '73,000, a printer's error, overlooked in last week's issue) has estab-lished electricity works in many countries, and has branches and agencies all over the world. The chief offices are at the Schiflbauerdamm, which is close to the Friedrichstrasse station of the Stadt-bahn, the elevated steam railway. In the elegant waiting-room there, the visitor notices among medals, diplomas, and other documents a con-gratulatory testimonial, presented by the staff to the directors in 1893, on the tenth anniversary of the company.

The chief factories of the A. E. G. are in the Ackerstrasse (arc lamps and apparatus); in the Brunnenstrasse (machines); in the Schlegelstrasse (incandescence lamps)- all within Berlin proper; and in Ober-Schoeneweide (cables), adjoinil1g the Ober-spree central power station. We had better follow the programme in our remarks; members found it difficult enough, anyhow, to put the notes they had taken, mentally or in writing, into their respective pigeon-holes.

THE A. E. G. CABLE WoRKs AT 0BERSPREE. The cable factory of the A. E. G., which the

party reached by rail and by special steamer on Wednesday morning, is situated on the Oberspree -that is, the Spree above Berlin, about 10 miles from the central offices of the firm. The works were opened in 1897, and enjoy the distinction of being

JULY I 2, I 90 I.]

the only German cable works which start from copper bars and draw their own wires. The party was re-ceived by Mr. E. Ra.thenau, director of the factory, and Mr. Wittmann, the manager, and the fire brigade of the firm did honorary duty. Like the adjoin-ing power central station of the Berlin Electricity Works and the German Niles Tool Works, a few minutes distant, the works lie very conveniently between the river and the railway at Ober-schoeneweide, which is best approached from Nieder Schoeneweide, on the opposite bank of the river, the station being about 20 minutes' walk from the factories. Both pls.ces are simply manufacturing centres, entirely modern; brass works, chemical works, &c., are also to be found. The curious feature is that while some of the married members of the staff dwell on the spot, the workmen live in Berlin. The absurdly high rents of Schoeneweide have partly to answer for this, and indirectly, we masr conclude, the uncertainty of the occupation must be thought of as one of the prime causes. The excellent care which most of these works take of the comfort of their staff, men, and women, is remarkable. In the dining-rooms 1nea.ls can be obtained at remarkably cheap rates, and coffee and water are kept in the shops of the A. E. G. We shall have more to say about these important social features. The start has generally been made by the firm, which appoints a contractor. The men, however, prefer to have a. co-operative association, more or less controlled by themselves. The large hall of the A. E. G. cable works, where the mem-bers were entertained at luncheon, might receive any fashionable assembly; it is used as a lecture hall. We may mention also the surgery and the ambulance car. .

The A. E. G. has replaced the old wooden bridge and ferry, by which the river was crossed, by a handsome wrought-iron foot- bridge, about 600 ft. in length, of three arches, which is lighted by arc lamps.

The cable works cover an area of 120,000 square yards, about three-quarters of which is under roof. Besides the cable factory proper, the works com-prise a factory for the manufacture of copper, brass, bronze, aluminium in bars, rods, and wires ; shops for the manufacture of insulating materials, notably the company's speciality, stabilit and micanit, rubber hose, washers, &c.; departments for covering, braiding, and stranding all kinds of wires with insulating materials; a department for making R ontgen apparatus and spark telegraphy apparatus ; lastly, machine and repairing shops ; a joinery, in which circular saws are fixed in lever frames, which can be turned about their horizontal axis, &c. The works need no special power central. The adjoin-ing Oberspree station sends currents of 6000 volts to the transformer station for the benefit of the many electric motors and lamps. Sixteen trans-formers reduce the tension down to 1000, 500, or 200 volts; their aggregate capacity is 2600 kilo-watts. Three motor-generators of a total capacity of 110 kilowatts supply continuous currents of 200 volts for the cranes, the accumulator shunting loco-motives, and for the indirect arc lamps, whose light is first thrown against the ceiling and then reflected back. There are two switchboards re-spectively for the 200-volt and the 500 or 1000-volt circuits.

The boiler-house supplies steam exclusively for drying, heating, and vulcanising. The ashes from the four multitubular Babcock and Wilcox, and the two Steinmilller, boilers, fall into trucks, which are removed and raised with the aid of an electric motor. The fuel is lignite, compressed to small briquettes, only a few inches square. This boiler-house adjoins an exceedingly neat pumping station, where one Riedler pump has been put down with three others. This pump deli vera 50 cu hie feet of Spree water per minute, running at 180 revolu-tions, and is driven by spur gearing from a 15 horse-power triphase motor ; it can supply water at 85 lb., the pressure of the hydrants.

The characteristic features of the works, which were finished in 1897, are the large spacious halls in which all crowding is easily a voided, and the absence of shafting. That is most striking in the metal and in the cable shops, and cannot fail to impress the visitor. The foundry contains fifteen furnaces, ten stationary ones, provided with a special side-blast, and five which are raised with the aid of a winding gear. Castings are produced of copper bronzes and aluminium ; and of bi-metals, steel cores round which a jacket of copper is cast, &nd double bronzes with an aluminium

E N G I N E E R I N G. core. In the mill three double sets of rolls, ar-ranged in two rows, reduce within a few minutes the copper bars, mostly electrolytic American copper, to 300 yards of wire of ! in. Each set comprises 21 rolls, through which the bar passes successively, and is driven by a triphase synchro-nous motor of 200 or of 600 horse-power by belt-ing or direct gearing. The same mills deal with the bronzes and bimetals. The aluminium is ob-tained from Pittsburgh and Neuhausen. A good deal of aluminium was to be seen, but most elec-tricians possibly remain a little cautious as to its applications. The further reduction of the copper and bimetal rods to fine wires of the smallest gauges is effected by means of diamond dies which yield wires 0.05 millimetre (0.002 in.) in diameter. The diamonds are mounted in copper, which is oast round them, pierced, and applied in multiple sets, consisting of a series of trays diminishing in size from the lowest to the top tray. There are ten multiple machines of this kind which draw the wire through seven holes at a time. In another hall bar copper is drawn out to be cut and sawn into commutator bars. Much attention is paid in all the works visited to protection against acci-dents. The German laws are very stringent in t his respect; but the sawing of yellow metal and soldering, do not appear to be subject to special restrictions.

The drawn wire is cleaned of oxide in baths of sulphuric acid and annealed in special furnaces, unless it is to be employed hard drawn. Copper plates of oval shape are rolled in Krupp machines and then converted into a long narrow ribbon by a machine which makes its cut near the circumfer-ence. The hot lead presses for the cable sheaths are of the Huber system, like those mentioned in the description of the Siemens and Halske cable works; the molten lead tanks at the Oberspree factory are, however, not covered on the top. For the insulation tests the pressure can be raised to 50,000 volts alternating. The places where such work is going on, are marked by red lamps, in addi-tion to the obligatory red-forked arrow, warning against high tension. Cables for tensions up to 1000 volts are insulated with paper, rubber, and impregnated jute. For still higher tensions the jute is wholly or partly replaced by rubber or by flexible stabilit. Stabilit, as is well known, is an insulating material of the A. E. G.-brought out by Mr. Wittmann; if we are not mistaken; it is made in a black and a brown variety and of different degrees of hardness. The flexible stabilit, though not elastic, can be bent to very short curves, and absorbs very little. These advantages were demonstrated by two comparative experiments, in which two cables with flexible stabilit insu-lation were tested against two cabl~s with paper insulation. Currents of 50 periods and of 9000 or of 30,000 volts were employed, and in both cases the energy absorption by the dielectric was about 30 per cent. less in the stabilit. This flexible stabilit can, owing to its high insulating strength, be applied in very thin layers. The manufa.cture of stabilit, which can be pressed into any shape, and also of micanit, which is built up of little plates of mica, stuck together with the aid of shellac, occupies many hands.

In the halls for the preparation, the masticating, kneading, and pressing of rubber and gutta-percha, the electric motors are placed along the walls, and drive the respective rolls by means of long belts. This rubber kneading is probably the hardest work that triphase synchronous motors can be put to; that they are efficient, members had already learned in the Siemens and Halske cable works. There was some discussion as to the fitness of synchronous motors in preference to asynchronous motors for such work ; synchronous motors, designed for large slips, are applied, however. Sulphur chlo-ride is used for vulcanising, and the vapours are drawn off from below. A real insight into these departments was not permitted. The rubber is applied to wires both by the tape method and the die method, which yields a seamless covering. The machines for insulating dynamo wires, flexible cables, and telephone wires, are placed en various floors, the finest silk covering frames, which run at 4000 revolutions per minute, being on the top floor. Large sand-boxes for quenching any fire could be noticed all over the cable hall and the rubber departments. The fire brigade consists of forty men, under the command of an inspector from the Berlin Fire Brigade.

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Befor.e luncheon the visitors examined various exhibits, particularly of stabilit a~d rubb~r, a~d witnessed some demonstration of high-tensiOn d~s charges one exper~ment ending, after a fine dis-play of' sparks, with the piercing of a large and stout glass-plate.

THE 0BERSPREE PowER 0ENTR.AL S'l'ATION. The luncheon and t he taking of a photograph on

the steps of the Oberspree power central of the Berlin Electricity Works, built by the A. ~ G., left members literally not more than a few minutes for the inspection of this fine station, which sends triphase currents of 600~ volts by undergr.ound cables to Berlin and neighbourhood, and IS to be enlarged to a capacity of 54,000 horse-power. Professor Slaby and Count Arco had, moreover, exhibited some novel improvements in their spark telegraphy and demonstrated the action of their instruments, as n9w installed on board the German Emperor's yacht Hohenzollern. Under the cir-cumstances, and as the A. E . G. possibly desires not to be anticipated in a description of their largest central station, we are not tempted to say much. The splendid large hall contains at present two . horizontal engines of 1000 horse-power; two ver-tical engines of 2000 horse-power (2400 maximum), each driving one generator on either side; two horizontal engines, driving each a 3000-kilowatt generator of the type exhibited at Paris last year. The old dynamos do not appear to have given com-plete satisfaction. The new dynamos and their four-cylinder engines of the Gorlitz Engine Works, fitted with Collmann trip gear, answer perfectly; and the shutting down of one of the units, running in parallel with the others, did not produce, in the secondary circuit, a variation of more than one volt. The large generators have an external diameter of 8. 6 metres (28 ft. ), anti the inductors a diameter of 7.4 metres (24.3 ft.); the inductor carries 72 poles and makes 83 revolutions. With a phase tension of 3640 volts, and a current intensity of 290 amperes per phase, for which the generators are designed, the engine should be capable of developing 4000 horse-power, and is hence not quite powerful enough. The windings consist of copper bars, insulated by mica tubes, and con-nected at their ends by forks ; good ventilation is provided.

In an adjoining room stand a few motor-gene-rators for converting triphase currents into con-tinuous currents; converters do not seem to be popular. The cables and the obliquely- fixed high-tension fuses are in the basement, where some horizontally-arranged triphase transformers can also be seen. From the barges, which land at the back of the works, the coal is taken by chain conveyors to an elevated rail-track, whose trucks deliver the coal into t he bunkers. Automatic stokers used to be employed. The boilers, partly Heine water-tube boilers, made by Borsig, work with superheaters by R aring, of Nuremburg, and economisers. The feed and con-densing water are directly taken from the Spree, and returned to the river after passing through the oil separators and a clearing tank.

A few supplementary words on the Berlin Elec-tricity Works. In December, 1900, there were joined to these six works 400,000 incandes-cence lamps, 16,000 arc lamps, 8000 eleotro-motors, and the Berlin electric street railways which are now deservedly popular. Accumu~ lator cars, which are still running in some streets of the inner city (in others, trolley lines have been conceded), got rather into discredit last winte~. The accumulators are charged with the aid of contact lyres from the trolley wires, where those are stretched, and no doubt the current regulation was not all that could be desired, so that occasionally cars got stuck. There is a certain suspicion, however, that the respective contractors were not over anxious to improve the . acc~m ulator service, since they had made up their mmds that the trolley wire should

everyw~ere be tolerated. That policy would, to a certa1n extent, be excusable. JEsthetic con-siderations should not be disregarded. But one cannot conscientiously object much to the trolley wires and their iron poles and brackets, even in the Thi~rgarten, through which the cars dash at an exhilarating speed, which horse trams could never maintain. It must be reme1nbered that all over the Continent tramcars stop only at their proper halts, which are indicated by iron posts. Some day we may see that practice universally adopted in

E N G I N E E R I N G. [JULY I 2, 1901.

TAL-Y-CAFN ROAD BRIDGE OVER THE RIVER CO WAY, ORTH W LES. ~IE~ R . DAY\7 ON AND }i'Y~ ON, ~LM. IN1 T. C.E., ENGINEER , \VE TniiN TER; niR. ALFRED THOR E, \VE TMIN TER, CONTRACTOR.

(For N otice, see Page 46.)

England. Before returning from this transgression we should mention that most of the Berlin electric street lines have been built by the Union Company and by Siemens and Halske ; the A. E . G. has done more in other towns.

THE SPREE TUNNEL. The Spree Tunnel between Stralau and Treptow,

a little above Berlin, through which the members were marched on their return to town, in order not to waste time by making a couple of hundred people change cars, is notable as the only subaque-ous tunnel of which Germany can boast. It was commenced in 1895, but owing to various difficul-ties, cutting through quicksand and wranglingwith the authorities included, it was not finished in time for the Berlin Exhibition of 1897, for which it had been planned. The tunnel has a length of 464 metres (about 500 yards), 374 metres being con-structed as t unnel proper with the aid of compressed air and a shield which was advanced by sixteen hydraulic jacks, resting against t he tunnel shell. The tunnel tube, which has a diameter of 4 metres (13 ft. ), descends to a depth of 12 metres (39.4 ft.) below the mean water level. The quick-sand gave a good deal of trouble, but care, electric light, and an efficient telephone service, prevented all serious accidents. The tu be rings consist of nine segments of mild iron connected by flanges and bolts, and the rings are held by hoops with stiffening ribs. The tube is lined with cement inside and outside. Over a length of 100 ft. of the cut-and-cover approach, the sheet piling could not keep the water out the portion was divided into t hree sections, and' compressed air was resorted to. A single-track electric tram way leads through the tunnel. THE A. E. G. WORKS ON THE AOKERSTRASSE AND

BRUNNENSTRASSE. By special t rain the party, now considerably

behind time, proceeded to the factories in the

FIO. 1.

Brunnenstrasse, where their arrival and the pre-parations made for them by the A. E. G., created some commotion. The Ackerstrasse factory dates from 1887, when the four-storey buildings in the Schlegelstrasse, which at present forms the oldest part of the works of the company, would no longer suffice. The Schlegelstraese factory was not visited. Incandescence lamps are made there, cellulose being pressed through nozzles, and the endless threads wound on bobbins, dried, cut, shaped, and carbonised. The factory can. turn out ten million fi laments annually. The Ackerstrasse factory has in its turn been reduced to the rank of a section, which can briefly be described as apparatus, and arc lamp, works ; t he chief machine works are now in the Brunnenstrasse, further to the north and approached by a private tunnel, 1000 ft . in length, through which a small continuous-current locomo-tive with overhead line passes to and fro. The locomotive was not used on the occasion of the visit, because tho transport of so many guests would have caused delay; members had to walk. The locomotive and the tunnel, which contains many cables, are a great convenience to the works.

The four-storey building of the Ackerstrasse covers with its four wings an area of 16,000 square yards, the available floor space being five times as large. Power is derived throughout from electric motors, and in those electrically ancient days t he installation of a common power central station with an electric motor in each room and counter-shaft and belt driving, constituted already a great advance. This central station of 1000 horse-power at present forms rather a reserve, as cables are led over from the Brunnenstrasse. The factory makes switches and switchboards, generally entirely of marble and iron, or of very neatly black polished slate with imitation wood frames of iron, provided with very convenient inclined desk ledges for the shuntresistances. Conspicuous was the switchboard for the Solvay electro-chemical works at Lubinow,

in Russia, for currents of 8000 amperes. The maxi-mum cut-outs are provided with spark extinguishers and signal lights. Maximum and minimum volt-meters give t wo kinds of warnings ; acoustic, by means of two bells of different size; and optical, by means of two lamps of different colours. The ordi-nary switchboard bronze forks diverge slight ly so that a very rapid interruption is obtained. The levers of the high-tension switches for phase cur-rents are as before attached to bent copper strips, which make the levers fly apart; the copper strips look stronger than those installed at Rheinfelden, but that may simply be a question of the now higher tension - 12,000 volts. Of the automatic cell switches for currents of 200 amperes and above, the wind direction indicators, and the ship tele-graphs, we shall have more to say in another issue. The ship telegraphs and steering apparatus now made for the German, Russian, Swedish, and other navies, are remarkably simple, and should therefore be reliable. Very compact and handy, also, are the triphase motor reversing switches, which resemble a vertically-arranged commutator and are operated by means of a horizontal handwheel. As a resist-ance material, nickeline seems almost exclusively to be employed, in wires, flat strips, and flat spirals, which are partly made by hand over a rod.

The benches for testing the various meters were all fully occupied; Dr. Benischke is the head of this department. 'Ve speak of a private visit, not of the visit of the Institution, which could not but disarrange the works a little. The A. E. G. makes shunt and differential arc lamps for continuous and alternating currents, the latter with aluminium discs. The small boring machines drill half-a-dozen and more holes at the time. Incandescence lamp sockets are also made at the Ackerstrasse.

Of the large works in the Brunnenstrasse the com-pany is justly proud. The works, which are bounded on one side by some of the original wires and

JULY I 2, I 90 I.] E N G I N E E R I N G. 4I

HORIZONTAL BORIN G MACHINE AT THE G LASGOW EXHIBITION. CON. TRUCTED BY 1\IE I R. . I HARP, I TEWART, AND CO., LIMITED, ENGINEER ' GLA GO'\V.

(Fo1 DescYription, see Pctge 46.) -

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insulators of the famous Lauffen-Frankfort power transmission (a fact which somewhat alarmed the daily press), cover an area of 120,000 square yards. The magnificent large hall, which is of one storey only, though g~lleries run round the two sides, occupies alone a. :floor space of 27,700 square yards. The general plan is such that the raw materials- there are spacious iron and brass foun-dries-pass in at the one side and the finished machines leave at the other, without having been moved backward and forward. An additional ad van-tage of this arrangement is that the dynamo wind-ing shop is on the opposite side to the aisles for mechanical and metal working, so that no injury from metallic dust need be feared. A normal gauge railway track, with numerous branches, divides the t wo departments. The whole hall is divided into fourteen parallel aisles, each 50 ft . in width, over which cranes of 20 tons travel. The heaviest masses are simultaneously transported by two such cranes, and it is thus possible to carry either a piece to the respective stationary machine, or to lift up heavy machines and put them down in proper position for the largest dynamo. The general rule is, however, single driving of each machine by electric motors, which are so well stored away and protected that they may be overlooked at a rapid glance. The foremen's offices, approached by stair-ways, overlook the different aisles. These huts are quite spacious enough to accommodate half a dozen draugh tamen .

The power t ransmission within the hall has been the work of Chief Engineer Lasche, an authority on toothed gearing. The motors are all on triphase circuits, and of different types. The small sizes up to 5 horse-power are constructed with short-circuit armatures, and switched in by push buttons; these motors can be directly used in connection with light and power circuits. Larger motors would unfavourably react on the ma.il1s, and are hence run with a. starting resistance placed in the stator; the torque is not altered thereby. Slip-ring rotors, with reRistance in the rotor circuit, are employed where speed regulation is desirable. A speciality of the firm is the step armature ; the resistance is in the rotor, but not variable, the armature having two separate windings. The low-resistance winding is left on open circuit in starting, so that the motor starts slowly ; the high-resistance winding is thrown in when the motor has attained about half speed. The resistance being contained

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in the armature, and hence of limited cooling sur-face, the motor cannot long be overloaded, and the speed admits only of the two-step variation ; but the motors are cheap and simply .managed, as they require neither slip-rings nor special starting re-sistanaes.

Many interesting and large-size machines can be seen : large planing machines, with a stroke of 20ft.; automatic wheel-shaping machines ; mul-t iple boring and slotting machines, already men-tioned ; horizontal lathes for armature frames up to 36 ft. in diameter, &c., and over fifty portable tools. The kind of dynamos made in these shops are known to our readers from our Paris Exhibition reports. Six of the large triphase generators, for 83 revolutions and 3000 kilowatts at 6000 volts and 50 periods, have now been installed in the Berlin Electricity Works, and fifteen more are under construction. They are driven by t riple-expansion four-cylinder engines of Messrs. Sulzer Brothers, of Winterthur, or of the Gorlitz Engine Works. We may remark that the engineers in charge of the engines did not express any decided preference for the engines of either company. The new Collmann trip gear of thd Gorlitz engines operates remark-ably well, and what the attendant appreciates still more perhaps- the engines are easily accessible. As regards coal consumption, r ecent Berlin trials favour the Gorlitz engin~s. But that hardly affects the high reputation of the Sulzer engines ; for the comparison did not concern t he most recent types of either maker. The big generators have a weight of 160 tons, the revolving field weighing alone 70 tons. The power central at the Brunnenstrasse contains t wo horizontal Gorlitz engines for 107 revolutions, driving t riphase 1200-kilowatt generators at 3000 volts, in addit ion to two smaller engines of400 horse-power and dynamos. The second large generator, which had only just been finished, is not con-structed with t he old cast ring frame of trough shape. The stationary armature is held by two lateral rings, built up of arcs and cross-connected by yokes, which are in their turn joined and braced by thi'eaded rods. Looking at the dynamo from the side, we see the polygon formed by these rods. The outer rim of the armature sheets is left quite bare and remains freely exposed to the air. Similar machines, of other makers, constructively different , however, were first shown at Paris last year, and some other open rim dynamos with stiffening on the front were also visible in the factory,

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and the type will be further developed. It is claimed that the construct ion, which is not a monopoly, is advantageous, even from the point of economy, although superior materials are required, because it adapts itself better to variations in size. The big generators are excited by means of motor-generator sets consisting, in the Brunnenst rasse, of a Pelton water-wheel, a triphase motor, and a. con-t inuous-current dynamo, all on one shaft. The Pelton wheel is added for the sake of starting with-out the aid of a battery. The P elton wheel is fed by an injector, and it turns the continuous-current dynamo. When the steam engines are in motion the triphase generators will give current to the motor, which can now drive the exciter dynamo; the Pelton wheel may then be uncoupled .

But we return to the large hall. Members noti\!ed the cupboards for tools, cupboards for waste cotton; the small cranes swinging about the columns ; tri-phase motors with combined short-circuiting and brush-lifting device ; armature cores with the one flanged end dovetailed and held by a ring ; a. model of a machine for exchanging tramcar motors ; the inductor for a 2400-kilowatt generator at 83 revo-lutions, the pole shoes of which are dovetailed into the rim into which they are sunk vertically, to be secured by a long wedge, and many other features. The iron and brass foundries and the brass-shaping machines would have claimed atten-tion if there had not been so much to be seen other-wise. In the large yards the castings ~n -be stacked in the same orderly manner that prevails every-where in the new shops.

THE HIGH-SPEED ELECTRIC LOCOMOTIVE. Mr. Lasche had put his truck for t he high-

speed electric locomotive in the yard, and it was t he first thing the members examined on their visit . The motor itself could better be seen in the large hall. The truck consists of two bogies with four axles, and the weight is 14 tons per axle. E ach truck bears two motors, which are not fixed on the axles, however, but are on a hollow sleeve, while band springs connect with the wheels. The wheel diameter is about 4 ft., and, running a.t 1000 revolutions with the full 1000 horse-power, the car is to travel at the rate of 125 miles an hour ; as a r ule, 700 r evo-lutions will do. The car will be fitted with 'V estinghouse and mechanical brakes ; electric braking is not intended. The t riphase motot

is not encased. The stator sheets are exposed on the rim, which is now the general practice of the A. E. G. for traction motors. No information was given about the further electrical outfit of the high-speed locomotive. It must broadly be of the type which Messrs. Siemens and Halske have adopted; for transformers will, of course, be wanted on the locomotive. We should think that there is no immediate hurry; for t hough one of the pamphlets, p ut into the visitors' hands, spoke of an opening of the Berlin-%ossen Inilitary railway within the course of this summer, matters are hardly so far advanced yet. We should also add that the experi-mental track of Messrs . Siemens and Halske near Lichterfelde is not to be confounded with their experimental track on the military railway, which is not accessible to the public.

THE DINNER IN THE ZooLOGI CAL GARDENS. Tired out, the members returned to their hotels,

juat in time to dress for the dinner given in the beautiful hall of the Zoological Gardens by t he Allgemeine Elektricitats-Gesellschaft and Messrs. Siemens and Halske. More than four hundred ladies and gentlemen sat down to this meal. The new Minister of Commerce, Mr. Moller, himself a manufacturer, proposed the toast of the Emperor William and of King Ed ward, to which, somewhat to the astonishment of the assembly and of t he leaders, who had taken care to limit the number of speeches, a member of the British Embassy felt called upon to reply. Director Rathenau, having welcomed the guests at the supper on Monday evening, Mr. Wilhelm von Siemens now renewed this welcome, and Mr. Alexander Siemens replied with warm thanks. The members, and not less their ladies, who had found most amiable guides in the German ladies' committee, had indeed reason for thanking their hosts. The toast of " The Ladies " --vas proposed by Dr. Raps.

The dinner did not terminate the Berlin viSit ; for the inspection of the Berlin Electric Elevated Railroad of Messrs. Siemens and Halske, one of t he most interesting pieces of the programme, was reserved for the following morning.

(To be conti-nued.)

ENGINEERING V ALU ATIONS. (Continued frorn page 2.)

I t will be patent to our readers that t here are serious defects in this ordinary method of arriving at new valuations of fixed assets by writing off an arbitrary percentage depreciation fr01n a previous valuation. Whether the use of a percentage is advisable or not, it is certain that it can only be fixed, if it is to make the slightest approach to accuracy, after careful consideration of all the cir-cumstances affecting any particular case, and after allowance for many factors which are usually ignored by accountants. Whether this disregard arises from ignorance of technical matters on the part of the financial authorities, or t he subordina-tion thereof to the preparation of a balance-sheet easily understood by shareholders, it ~s unnecessary to inquire ; but the engineer who desires to be pre pared to make, or to consider, proposals for pur-chase of his works, either by an actual cash pay-ment or amalgamation with other con1panies, must provide himself with some more correct method of continuous valuation, and more accurate way of calculating the depreciation on which that valuation

.. will be based. It is absolutely necessary that the charges for

maintenance should be debited against the revenue of the year, and not added to the value of the buildings or plant: In some few firms. the oost of maintenance, repa1rs, ancl of r enewals 1s added to the previous valuation standing in the books, .and from the amount thus arrived at depreciation is written off; and this courae is j ustified on the plea t hat depreciation and maintenance cannot be sepa-rated from each other, and that the one should balance the other. The fallacy of this will be per-ceived when we consider the tendency of machinery to become obsolete through the introduction of improved types, and of buildings to become un-suitable through extensions of t rade ; and t~at the most extensive repairs done to any mach1ne or building cannot by any poss.ibility do m?re th~n plaoe it in as good and workhke form as 1t was 1n the first instance. .

The repairs are a necessity incident to, an~ 1nl-posed by user ; depreciation may include thts, ~s a form of accoun t, but it includes much more m

E N G I N E E R 1 N G. decay inevitable through lapse of time, and im-provements developed by the ever-active human intellect. Even renewals will not in all cases fully compensate for the decline in value, and restore the assets to the amount at which they were taken in the original balance-sheet. If the renewed machine or building is an exact replica of the former one, it will be of leas intrinsic value because of the year~ by which it will be nearer supersession ; if it is of later or improved type, the money cost of it may be more or less than that of the original, being affected by the market prices at the time of purchase, which prices are in t ime affected, not merely by supply and demand, but in these present days by apprecia-tion of gold. It must always be remembered that it is the market, t hat is, t he selling value of the factory and its equipment, which is being sought, and not any estimation based on utility to the present ownel'S. If, therefore, the amount written off for :lepreciation has to bear t he burden of ordi-nary repairs necessary for the '' up-keep " of the buildings and plant, without which they would speedily fall into decay, as well as renewals, and replacements, and loss through lapse of time, for which it was primarily intended, it is probable that it will be feund inadequate. The scale will usually be adapted to the latter charge, but will be insufficient for the former, which will be looked upon fondly, but falsely, as increasing the value of the factory .

It is true that Parliament has recognised the combination of maintenance and renewal charges in railway accounts. In abstract A of the annual return directed by ' ' The Regulation of Ra il ways Act, 1871, " the cost has to be stated of '' main-tenance and renewal of permanent way ;" whilst abstract U has to contain the same information with respect to ' ' repairs and renewals of carriages and wagons." But railways differ from most engi-neering undertakings, both in the permanence of their character, and more particularly in the factors which govern their sale and purchase. The primary considerations in acquiring a railway are the amount of traffic which it carries, the character of the country it passes through, and the assistance it will render to the purchasing company in the capacity of a feeder ; these, much more than the exact past division of expenditure into capital and revenue, are the points looked at by a traffic manager. Former blunders may affect or prejudice the original shareholders, but they are probably remediable under the changed conditions of future management. Although, t herefore, 1ail ways are required only to render statements of their expen-diture under forms in which the cost of maintain-

iog the road and ro11ing stock, and the payments for new rails or new wagons and carriages for renewal thereof, are mingled, yet the special condi-tions of this kind of enterprise are so different to those governing manufacturing establishments, that even the wisdom of Parliament will not justify the adoption of such a procedure generally.

When, however, provision is made, by the execu-tion of ordinary repairs, for keeping the buildings and plant in good and sufficient working order out of revenue, it is necessary to ascertain some rate of depreciation which, by an accumulative fund, will prevent loss of capital to the sha1eholders. But here we are met with the difficulty of fixing a rate or scale which will apply to all classes of assets and under all conditions of time and user. Even Mr. Dicksee, writing only with the experience of an auditor, and without special reference to the varia-tions of conditions in different t rades and localities, was compelled to adopt different rates of deprecia-tion, ranging from nothing in the case of freehold lands to 15 per cent. per annum for machinery, and 25 per cent . per annum for horses. Both for correctness and convenience his method was a wise one. I t is desirable to divide the assets into classes for valuation and scale of depreciation, and to consider each class independently and on it." own merits, and with reference to the special circum-stances which may affect it. Even in the case of the purchase or sale of a factory as a going concern, this division is still necessary for the purpose of computation ; the price agreed upon may be the aggregate sum, but th~ items must be separately estimated if the result 1s to approach correctness.

F1eehold and Leasehold Lwnd.-I t is a generally accepted opinion with auditors ~ha:t fr~ehold land does not vary in value, and that It 1s q ut to unneces-sary to write anything off the origina~ cost price of it. This, however, is, under some cucumstances, a delusion, although it may be true of the average

[ ] UL Y 11, I 90 I. district where trade continues prosperous. Mr. H erbert Spencer, in his "Principles of Sociology," says: '' In England t he first building containing many machines thus simultaneously driven was the well-known silk-throwing mill at Derby, erected early in the last century by Sir Thomas Lom be. The example he set was followod in cotton-spinning by Arkwright, Crompton, and Hargreaves . 1'heir mills were of necessity erected on the banks of rivers yielding the requisite fall of water, a 1equirement which dispersed the manufactul'ers to scattered places, often to remote valleys. And here we are introduced to another of those great changes in industrial organisation which have been initiated by scientific discovery and resulting mechanical appliances. For the revo-lution which gave to the factory system its modern character arose from the substitution of steam power for water power ... Another result was that wide distribution of factories was no longer necessitated by wide distribution of water power. " Mr. Spencer uses the illustration to explain one portion of his general theory of evolution ; and in admiration of his majestic generalisations we are apt to lose sight of some of the side-lights he throws on details which, rightly considered, have a practical value, and teach a practical workaday lesson. The great change which he indicates from water power to steam power deprived land in the neighbourhood of streams of the additional value conferred upon it by its adaptability for factory purposes ; a value which was in the nat ure of a monopoly so long as water power was the only, or principal, motor available. When, however, this monopoly value was removed, and other compet-ing conditions had free play, the trade gradually left t he stream-served valleys and became fixed in large centres of population, where increased advantages arising from means of transport, and concentration of workpeople, could be obtained. But the buildings so abandoned would probably prove unsuitable for other trades ; we can, in the Rossendale V alley and other remote corners of Lancashire, see ruined buildings, now unoccupied, which once were prosperous factories. They cannot be used as manufactories ; it will hardly pay the cost of labour to remove the stones ; and the cost of ret urning the land to agricultural purposes, even after the buildings have been pulled down, will be considerable. Here is a clear instance of deprecia-tion in the value of land, not arising from lapse of time, but from change of conditions. It was pro-bably purchased- in the majority of cases cer-tainly would be purchased- at a price representing its value as the location of a manufactory ; but at best it can only be sold for agricultural land, and that. at an inferior price, since its dirty and uncul-tivated condition will render it unproductive, or less productive, than neighbouring land, for some considerable period. It will, in fact, be reduced to ''prairie value," and in the absence of some special demand or for tuitous conditions in the district, will only bring such a price when sold. Again, a fall in the value of land, apart from the buildings thereon, may occur in one part of a large town, in consequence of the opening up of additional facilit ies in a distant portion of the same town, and the migration thereto of other offices and manufactories. Such a process will probably be a gradual one, but each additional removal of a workshop from the decaying district to the growing one will accelerate it, unless the land can be utilised for other purposes, such as workmen's dwellings, or further increase of re-tailers' shops and stores. Or there may be through-out the whole town a depreciation in the value of real estate, owing to depression in the piincipal employments of the inhabitants, even though the particular factory under consideration may have been prosperous, or, at all events, paying its way, during the recent period of its working. An in-stance of this character is r1uoted by lVIr. Mellors, a chartered accountant and estate agent in exten-sive practice, when giving evidence on July 17, 1896, before the Lords' Select Committee on the Bill for the amendment of the Companies Acts. The Earl of Leven and Melville had been enquiring what would be the effect of stating in a published balance-sheet the temporary market value of bills held by a company, instead of their face value, in the event of a panic like Overend and Gurney's Black Friday. Mr. Mellors replied : '' There is no need to limit it to bills ; it will apply to real estate. In Nottingham we have had a depression for 10 years, from 1884: to 1894. During t hat 10 years, if

J ULV I 2, I 90 I.] .

real estate had had to be re-valued, it would have had to be valued at 30 per cent. lower than either now or previously to the time I have named. Then with regard to machinery ; during seasons of de-pression of trade machinery goes for what is com-monly called ' an old song ; , so that there is no question that it would be Tery difficult to publish a balance-sheet in such times in which the exact market value of the assets was given fairly ; and it would be a hardship upon a company to compel it to write down its assets in that way.,, 'l,he ques-tion of machinery does not at present concern us ; we are for the moment considering the land, and it is evident that Mr. Mellors, from his own experi-ence as an estate agent, knows that depreciation of real estate may take place, even to the extent of 30 per cent. It is true a recovery in value has now taken place, but during the 10 years of depression the minds of owners must have been severely exer-cised by the reduced value in their assets ; and they might possibly have been compelled to sell during the period of these lower prices, when the pro-spective loss would have become an actual one. It is not given to every prophet to foretell the succes-sion of seven years of fat kine after the seven years of lean ones.

The variation in the value of land may be in the manner of an increase instead of decrease. Such change will almost invariably follow on the transfer of industrial enterprise, either from the watersides of the valleys to larger towns, or from one portion of the town to another ; the land in the district which is in course of becoming congested will un-doubtedly rise in price, and probably with more certainty and greater rapidity than that of the deserted portions will fall. The available quantity of land is limited, and cannot be increased to meet the demand, whereas the abandoned land may possibly be used for other purposes. The opening of a new railway, or the building of a new and improved station, with increased siding accommo-dation , and facilities for junctions with private lines, or the complet ion of a large and well-equipped canal, like the Manchester Ship Canal, will cause a demand for land for building purposes in the neighbour-hood, which undoubtedly will produce a rapid rise In priCes.

Such variations in land values are undoubtedly difficult to deal with, and the more so as such changes, sometimes extending over a far larger area than manufacturing districts, are very varied iu character, and, being subjected to other con-tingencies, do not always afford sufficient guidance on which to formulate any absolute rule. Thus the agricultural land in some of the southern and eastern counties of England will not only fail to sell at the prices ruling twenty or thirty years ago, but is often unsaleable at any price; whilst urban land, suitable for villa r esidences or workmen1S cottages, in the same counties has actually appre-ciated during that time. Again, whilst land is of increased value and almost unobtainable in a prosperous town like Bury, it has shrunk in price and become practically unsaleable in many of the valleys near thereto, where successful mills were once working. And yet correct estimation of the financial position of the firm demands that in some manner or other the depreciation or appreciation of land shall be given effect to, unless it is undoubtedly temporary in character . The first consideration, therefore, for the engineer to determine is whether it is permaner1t or temporary. And here it is necessary to state that although many of the determining causes, such as suitability of site, are incident to his own particular t rade, and may be given effect to in his own individual calculat ions, others are such as can only be estimated by an estate agent as valuer , skilled in t he prospects of the property in that part icular district. The migration of one par ticular t rade does not necessarily involve lower prices for the land on which the abandoned works are built. It may possibly be u~ilised for other p urposes outside the engineer's ken, but the anticipation of which will present itself instantly to the pract ising estate agent.

Where the deser tion of the district, or prospec-tive desertion, arises from its becoming unsuited for trade purposes, through changes in methods of "or king such as that arising from transition from

w~ter to steam power ; or through insufficiency of railway and canal accommodation, thus involving

increased transit charges over competing districts ; or through difficulties in providing housing for suffi-cient, and increasing,f numbers of workpeople,

E N G I N E E R I N G. without burdening them with toiling ~ver long dis-tances to their work ; then t here 1B re~sonable probability that the fall in value will be perma-nent, that not only will the buildings bec~me valueless save for such price as the old ma.tel'la.ls may bri~g, but the land itself will return to agricultural value, subject., however, ~o ~he e~penditure thereon of a suffic1entsum to bnng It again into agricultural use. For it must be remembe.red that the correlation of trades at the present t ime is such that a dist rict or town unsuited for one class of business will also be frequently found un-suited for allied but dissociated t rades, and that the dist~dvantages under which it labours will be greater than the advantages which can be offered in reduced rents or cheaper land. No new trades have taken the place of t he decaying indust ries of the Stroud or Rossendale valleys ; and their in-habitants have to subsist on the fragments left them of those employments which find their fullest development elsewhere. That a revival may take place, and a return of prosperous trade be effected, even after such adverse straits, is undoubtedly possible, but the probabilit ies. against suc~1 reviy~l are so strong that no wise business man will ant ici-pate it in preparing an estimate of his assets and liabilities.

It is, however, seldom that permanent fall in value of land is sudden in its operation. The instance of Nottingham, referred to by Mr. Mellors, is, indeed, an example to the contrary : the depre-ciation in the land values arose from temporary depression in the staple t rades of the place, and from their transfer to other places; when trade revived, the selling price of land went up to its normal rate. There is thus an interval between the fat kine and the lean kine, of which ad yantage can, and ought to be, taken to write off from the revenue of the company a sufficient sum to compen-sate for the diminishing value of the land asset. The annual charge may be dealt with in any form most convenient to the circumstances of the com-pany ; the particular method does not concern us at the moment; but it must be adjusted so as to extinguish the loss in value by the time it comes into operation. To preintimate this date requires considerat ion of many factors, some of which are purely connected with the prospects of the trade, whilst others are dependent on the more varying moods of human emotion. It is a question of average, but withal one so complex that it will be found difficult to avoid errors in deciding it. I'robably commercial experience, and knowledge of mankind, will be more serviceable than efforts after actuarial accuracy.

Although, on the one hand, there is a possibility of shrinkage in the value of land, there is, on the other, a strong probability that in other districts it will be increased ; indeed, the very process of removal of works from less desirable localities to more desirable, will cause some increase, though not necessarily an exactly corresponding one, in the price of land in the latter places. The opening of the M~nchester Ship Canal, and the increased transport facilities and reduced transit rates offered, or expected, in consequence, have caused an exten-sion of new works into its neighbourhood; and this tendency will be accelerated, both by the proclivity to follow a leader, which is as pro-nounced among men as among sheep, and also by the aggregation of workpeople and workmen1s dwellings, which speedily follow. The advantages which are expected are thus of a twofold characte.r; reduced expenditure for carriage, and ready supply of labour within reasonable distance of the works. But as the transition from a prosperous manufac-turing valley t o an inferior sheep walk is a gradual process, r equ iring many years to accomplish, and affording time to provide against loss of capital by reducing the available distribution of net revenue, so the growth in value of a new district will be a gradual one, and afford to the earlier settlers opportunities of making profits which do not, strictly speaking, arise from their manufacturing ht!siness. The land when first purchased may have been agricul-tural land of more or less fertility, or waste moor-land of little value, and the purchase price which appears in the first balance-sheet may have been a very low one. The cost of clearing and preparing the site, and of constructing roads and approaches, should appear under the head of land value, although by some accountants and auditors it is classified with buildings where land and buildings are placed in separate items ; but whichever method is adopted, execution of this work in

43 >

general increases the value of the pr~mises to a greater extent than its actu~l co~t. In hke manner with the opening of a pubhc rallroa~, tramway, or canal, though in a emal~er degree ; It has rende~ed land available for a vanety of purposes for which it was previously unsuited, and i~creased the profit which may consequent1y be obtained fr?m the sale of it in a ratio greater than the expend1t~re neces-sary for makin~ the. approaches. This would readily be perce1 ved 1f the land were rented on year]y or short term tenancy : the rent de-manded, and paid, for lan~ properly levelled, and with good roads to It, would be more than for rouo-h ground with no approaches, and the extra re~t thus paid would, in most cases, be greater than the interest on th~ extra. e~penditure involved. It is .perfect~y ~1ght, and 1n accordance with sound busmess prmciples, to take account of this increased value of the land, at all events in the private records of t~e company, eye!l if it should not be deemed advisable to exhibit such variations in the published balance-sheets whilst they remain merely approximations.; when the profit or loss is fixed by actual sales, It must appear in the accounts submitted to the share-holders.

(To be contmued.)

THE AMERICAN SOCIETY OF MECHA~ NICAL ENGINEERS.

(FROM OuR NEw YoRK CoRRESPONDENT.) (Continued j1om page 23.)

TITANIUM IN CAST IRON AN]) STEEL. The first paper of the next morning session was

'' Influence of Titanium on the Properties of Cast Iron and Steel,' , by A. J. Rossi. Now, titanic acid has been supposed by many wise men to exert as evil an influence on these metals as t.he :New York Committee of Fifteen does on the Tammany officials, leading them to do everything undesirable, and to fail to do everything desirable, and causing them to become refractory, and to absolutely refuse purification or betterment of any kind. So Mr. Rossi was hailed as a benefactor if he had a good word to say about titanic acid.

After detailing various experiments at length, and showing by diagrams their results, Mr. Rossi gave the following as his deductions :

In conclusion, we believe ourselves justified in saying thab, as far as cast iron is concerned, the improvements observed by additions of small percentages of titanium alloys cannot be contested, corroborated as our results have been by experiments made by obhers, and indepen-dently from us. They bear both on the transverse and tensile strength, which are increased, the former some 20 to 25 per cent., the latter 30 per cent. or more, accord-ing to quality of the original pig iron. As to steels, limited as our experiments have been, and limited to crucible steel as they were, the influence of titanium seems to have been very much in the same direction as as for ca.st iron- an increa~e in the ductility of the metal, as shown by the increased contraction of area and elongation and of the elastic limit in high-carbon steels.

In respect to other metals than iron, Mr. Rossi's conclusions were :

Any titaniferous iron ore, sufficiently free from injurious elements and high enough in titanium, will prove suitable for a firsb material. The powdered ore is intimately mixed with powdered charcoal, and the mixture charged in the graphite cavity of a block forming the electric surface, or crucible. Its construction is very much like that described by Siemens some 20 years ago. This graphite block and its contents form the cathode. A set of carbons, bunched together and forming the anode, penetrates in the central cavity of the furnace, leaving between the carbons and the sides of the crucible a space sufficient for the introduction of the charge. The lower-ing or raising of the carbon anode, by means of any a.ppropt.ia.te mechanical device, allows the arc to sba.rt through the mass, the heat generated being sufficient (proba~ly so~e 2~00de~. C., more or less) to ~ause the reduct1on of titamc oxtde of carbon, a. reductton which reguires this intense heat, the iron oxides of the ore bemg, of course, readily reduced in these condition~. The two metals melb, and alloy and the earthy materials of the ore float as ala g on the surface of the metallic bath. With the ores which we have used, the amount of this slag was very limited. The proporbion of titanium to the iron in the ores treated necessarily fixes and limits the percentage of the first metal in the product. If this is higher than is desired, a certain amount of scrap iron can be added to the mixture of ore and carbon and charged in the furnace firsb, in order to obtain any other J?,er-centage desired; but there is a maximum posstble deJ?ending upon the composition of the ores themselves.

We have thus obtained alloys containing from 5 to 7 per cent. of carbon (more or less), mostly, as we have said in the gra.phitic state, and titanium in variable propor: tions froll} about 10 per cent. to 25 per cent., or more. For certa1n purposes the presence of carbon may prove

44 objectionable, and we have made alloys containing b ub 0.18 t_o 0. 'JO of carl?on, operating in the same furnace, by substit_utmg: alummum for carbon as a reducer of the met&lhc ox tdes. This property of aluminum to reduce nearly all metallic oxides has been known for the last 60 y~rs

JULY I 2, 190 I.] E N G I N E E R I N G. 45 UNIVERSAL AND CUTTER GRINDER. '

c 0 NI rr R u c '1' E D By MR. A. F A L KEN A. U, EN I IN E ER, pH I LAD EL pH I A.

(For Descr'iption, see Page 46.)

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A hole for the wedge is then drilled and rea.med at an inclination with the axis of the ora.nk-pin of about 1 in 10. In this hole a. oy lindrioa.l plug is inserted. It is ma.de an easy-sliding fit, but is temporarily held fast during the following manipulations by a wedge-key or other means, while the hole for the crank-pin bushing is bored at ris-ht angles to the axis of the rod. Both holes are oylindr1oa.l, but their angle to each other makes the plug a wedge, convex on the right side and conoave on ~he bearing aide. The holding key is now removed, and the plug is free to move any 4ista.nce in the direction of

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its axis ; but if it is moved endwise, it will throw the concave side towards or from the crank-pin. To adjust and hold the plug in position, a screw is fitted with two collars to em brace the ends of the wedge. This screw may be fitted wrench-bight to hold it securely in any posi-tion, or it may be held by other means in large bearings.

To illustrate the delicacy of adjustment1 we may assume that the axis of the plug is at an inolina.t10n to the crank-pin of 1 in 10, the screw out with 20 threads to the inob, and the head slotted with 5 notches 72 deg. apart; then the revolution of the sorew notch will move the plug one hundredth of an inch axially, and adjust the bearing towards or from the crank-pin one thousandth of an inch.

The ri~dity, acouraCf, and delicacy of adjustment of this bea.rmg are shown 1n the marine form of rod. The bolts of the cap are drawn up tight and looked, thus holding the oa.p and the rod metal to metal, making it in effect as rigid as a solid end rod. The adjustment of the

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bearing is then made as frequently and M delicately as desired. For large marine engines, mechanism for working the adjustment could be carried to a. point near the crosahead, ad that the bearings of both the crank-pin and the crosshea.d pin could be adjusted with the greatest facility, even while the engine is in motion. The more massive the rod the greater are the advantages of a rigidity that does not affect t he ease and delicacy of ad-justment.

The end pressure on the plug from the load is the re-sultant of the angle of inclination used, less the sum of the frictions on the two opposite surfaces of the wedg~. Pro~rtions can be used that will result in a practical equilibrium so far as the end motion of the plug is con-cerned.

A diagram showed the application of the adjustment to an ordinary valve rod, in which the adjustable parts are placed in the rod in such a manner as to have the wear of the bearing!! affect the centre-to-centre length the least possible. The variation is here the difference in the wear of the two bearings instead of the sum of their variation~, as is the ca.se in the usual arrangement of the adjust-

men~. The very rigid form of this bearing, together with its delica.te and accurate adjustment, makes it suitable for minute adjustments required in stamping presses.

It will be noticed that the adjustment of the bearing is a. parallel motion with large bearing area.tl, accurate sur. faces, and little or no tendency to get out of adjustment, either from long use or faulty manipulation. The deli cacy of the adjustment, the mecha.mcal accuracy of the bearing, and the decrease in the cost of manufacture over the ordinary designs, will be evident to ehop men. 'l'h~

bushi~g is o~ the best f?rm for securing accurac.v of form combmed w1th econom1c manufacture. The bushings can be. r~newed ab a comparatively small expense, when the

or1gmR~llength of the rod will be exactly restored. ExcunsroNs.

That afternoon the entire party took the ever-present and most useful t rolley-cars, a,nd went to Waukesha to sample the famous springs there. The ride was a beautiful one, and Waukesha is a lovely place. We started our work of sampling in good faith. After trying the waters of four springs, some wise or over-full individual asked how many springs there were; and on being told some thirty-six in all, the entire party became thoroughly dis-

c~uraged, doubted their capacity, and promptly de-cltned to proceed. Some even went so far as to seek for antidote for what they already had t.ried ; and your correspondent has no hesitancy in saying that Waukesha water, properly diluted with " spiritus frumenti, " is not only absolutely not deleterious, but even exhilarating. We returned to our hotel in excellent spirits, or rather with excel-lent spirits; and later had another of those delight-ful "smokers" which were such a distinctive feature of this meeting.

(To be continued.)

TAL-Y-CAFN BRIDGE. WE give this week, on page 41, a general view of

the TalyCafn Road Bridge, constructed over the River Conway, in North V\Tales, while on our two-page engraving we illustrate some of the details, particu-larly of the masonry piers and abutments. In a future issue we shall giYe further engravings illustrating the detaib of the superstructure, and we P!fopose to post-pone any complete account of the bridge until t hese illustrations appear. Meanwhile we may say that the river portion of t he bridge includes a central span of 150ft. and two aide spans of 90 ft. each, while there is also a shore span of 20ft. over a roadwa.y. The engineera of the b ridge were :Messrs. Dawson and Fyson, ~IM. Inst. C.E., Westminster.

BORING MACHINE AT THE GLASGOW EXHIBITION.

IN many machine shops the question as to what is the best form of boring machine has been much debated. Can holes be bored more truly with a vertical spindle than with a horizontal one ? Some of the newer school of engineers have taken a violent fancy to the ver tical spindle, advocating its use for any ~tnd every purpose, riding their fancy to such an ex tent that one would imagine that they will not stop until they have turned up on end all the lathes in the machine shop. At the same time they will declare that with a horizontal spindle it is an impossibility to bore a hole truly cylindrical. The average engineer has not yet, however, lost his faith in the horizontal spindle; whether it be found in a lathe or in a boring machine. Both in America and this country some excellent boring machines are being built ; for instance, quite a special Jine of boring machines with several horizontal spindles is now being produced in the former country for boring the cylinders and valve chambers of Corliss engines at one setting.

That there has been room for improvement in the design of the class of machines about which we are speaking, with a view to the more speedy setting of work, is without doubt, and it is with considerable pleasure that we draw attention to a machine, made by Messrs. Sharp, Stewart, and Co., which shows a successful effort to modernise a horizontal boring machine. We present a half tone of this on page 41, and those of our readers who m~y be at Glasgow before the close of the Exhibit ion may have an opportunity of seeing the machine itself, in the Machinery Hall. It fulfils three several functione, for it is intended to act as a boring, drilling, and screw cutting machine. The general framework somewhat resembles that of an ordinary high-cent re lathe; but that the machine may fulfill its various functions, the other parts correspond-ing to similar parts of a lathe are modified to suit the machine's special use.

How often has a machinist in a jobbing shop used his lathe for boring a hole in a piece of work ? Some lathes, in fact, a.re made with .l. grooves to facilitate the bolting down of such jobs on the saddle. The n.achinist, though, has to pack his job with strips of metal or pieces of wood to bring it into line with his lathe centres. '\Yhen looking at the machine one can imagine that t~e ~esigner ~a~ in his mind a mental picture of the JObbmg machm1st, and that at the same time he had formed a r esolution to produce a machine which has the same general idea as the lath~, but with modifications introduced that should render the method of machining most simple.

There is a saddle of ample proportions, but the upper portion, corresponding to the cro.es-slide, carries a grooved table ; and with the aid of el~vat.iug scr~we

E N G I N E E R I N G.

both back and front, connected through the medium of a cross-shaft with bevelled wheels, this upper slide, wit~ the ta?le, may be raised or lowered to get t he vertical settmg of the work. To fur t her facilit~te the setting of a casting to be machined, the table can be adjusted on the transverse slide, and its upper part is

al~~ !Dad~ to swivel ; tl~us ~he bringing of a job to pos1t10n IS very much sunphfied, and packing pieces are only required to steady the work or prevent it from springing. In the stead of a loose headstock there is a pedestal to receive bushes, and these in turn form the tail bearing for the boring bar. But one bor-ing bar is, ~sa r ule, ~upplied with each machine, t hough others of d1fferent dtameters can, of course, be added.

The main spindle is hollow, and r uns in parallel capped bearings of gun-metal, with adjustments for taking up wear.

The steel-boring bar is attached to the boring head, and that, in turn, is connected to the feed screw in su.ch. a ma.nner that all thrust is received upon anti-fnctlOn rmgs, and there are fine-thread nut adj ust-ments to prevent backlash. The boring head and bar Plide within t he main spindle, which makes it possible for the machine to be reasonably short. W ithin the interior of the machine-bed there is a steel guide screw, and this is driven by change gearing from the main spindle, so that the saddle carrying the table may be given a self-acting sliding motion. A release nut attached to the saddle ma.kes it possible to uti lise this motion for internal threading. Automatic transverse motion can also be given to the table. For use when facing castings, a balanced facing-slide and tool-holder for attaching to the boring bar is provided. This may be seen in the illustration upon the ground to the left of the machine.

The following are a few dimensions : Size of boring bar admitted in the main spindle is 3! in. in diameter; the length of machine-bed, 11 ft.; traverse of boring bar, 3 ft. 6 in .; longitudinal traverse of table, 2ft. 6 in.; transverse traverse of table, 3 ft . ; vertical traverse of table, 1 ft. 10 in.; size of table, 3 ft. by 4 fb. It is possible that when an advocate of the verLical spindle has inspected this machine, he may come to the conclusion that there is still virtue in one upon a horizontal axi~.

UNIVERSAL AND CUTTER GRINDER. WE illustrate on pages 44 and 45 a. grinding machine

intended both for cutter grindiug and general use, made by :J.\Ilr. A. Fa.lkenau, of Philadelphia, and now being introduced in this country by Nir. Thos. A. Renshaw, of 8, Bathstreet, City-road, E.C. As shown in the general view, the machine is arranged for cutter grinding. The emery-wheel runs in adjust-able bronze boxes provided with dust caps to protect the baarings from grit. The cutter carrier is shown in detail in Figs. 2 to 4, and with a cutter in position in Fig. 5. The carrier is provided, it will be seen, with a horizontal and vertical traverse, and also with rotary movements round both a vertical and a horizontal axis, and hence cutters of the most awkward shape can be easily brought into position for sharpening. Gear cutters are, however, not ground here, but on a separate attachment shown in Figs. 10 to 12. This runs on the upper guide of the machine, on which t he poppet heads are shown in the general view. The cutter in this case revolves on a vertical axis, and is held steady whilst being ground by the stop shown in Fig. 10. The /oppet heads are clearly shown in Figs. 7 to 9, an in Fig. 17 is shown the arrange-ment for revolving the work when it is being ground on de,ad centres. It will be seen that a loose pulley runs' on the spindle surrounding the centre