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Scientific American Supplement, No. 586, March 26, 1887试读：
NEW YORK, MARCH 26, 1887
Scientific American Supplement．Vol．XXIII, No.586.
Scientific American established 1845
Scientific American Supplement, $5 a year.
Scientific American and Supplement, $7 a year.
THE RETIRO VIADUCT.
We give engravings of the viaduct over the river Retiro, Brazil, our illustrations being reproduced by permission from the Proceedings of the Institution of Civil Engineers．In a "selected paper" contributed to the volume of these proceedings just published, Mr．Jorge Rademaker Grunewald, Memb．Inst．C.E., describes the work as follows:
VIADUCT OVER THE RETIRO, BRAZIL.
This viaduct was constructed in the year 1875, according to designs furnished by the author, for the purpose of passing the Dom Pedro Segundo State Railway over the valley which forms the bed of the river Retiro, a small confluent on the left bank of the river Parahybuna．It is 265 kilometers (165 miles) from Rio de Janeiro, and about 10 kilometers (6.4 miles) from the city of Juiz de Fora, in the province of Minas Geraes, Brazil．It has a curve of 382 meters (1,253 ft.) radius, and a gradient of 1 in 83.3．Its total length is 109 meters (357 ft.7 in.); width between handrails, 4 meters (13 ft.); and greatest height above the bed of the river, 20 meters (65 ft.7 in.).
The viaduct is composed of seven semicircular arches, each end arch being built of ashlar masonry, and of 6 meters (19 ft.8 in.) diameter; five intermediate arches, 15 meters (49 ft.2 in.) in diameter, are of iron．The four central piers are of iron erected on pillars of ashlar masonry．The metallic part of this viaduct is 80 meters (262 ft.6 in.) long, and is constructed in the following manner: The arches, and the longitudinal girders which they support, are made of two Barlow rails riveted together, with an iron plate ½ inch thick placed between them．The spandrels are formed of uprights and diagonals, the former being made of four angle-irons, and the latter of one angle-iron．Each pair of arches, longitudinal girders and uprights, is transversely 3 meters (9 ft.10 in.) from center to center, and is connected by cross and diagonal bracing．On the top of the longitudinal girders are fixed cross pieces of single Barlow rails, upon which again are fastened two longitudinals of wood 12 in．square in section, and which in their turn carry the rails of the permanent way.
The gauge of the Dom Pedro Segundo Railway is 1.60 meters, or 5 ft.3 in．nearly, between the rails．At each end of the transverse Barlow rails is fixed the customary simple iron handrail, carried by light cast-iron standards．The iron piers are each formed of four columns, and the columns consist of two Barlow rails, with a slotted iron plate ½ inch thick let in between the rails, and the whole being riveted together connects each pair of side columns.
The details show the system of cross and diagonal bracing．The columns are each supported by four buttresses formed of plates and angle-irons．These buttresses, fastened with bolts 8 ft.3 in．long, let into the masonry pillars, secure the stability of the viaduct against lateral strains, due mostly to the centrifugal force caused by the passage of the trains.
The Barlow rails, which constitute the peculiarity of the structure, are from those taken up from the permanent way when the Vignoles pattern of rail was adopted on this railway．The whole of the foundations were built without difficulty．The principal parts of the iron work were calculated to resist the strains resulting from a weight of 4 tons 8 cwt．per lineal meter traveling over the viaduct at a velocity of 60 kilometers, or about 37 miles, per hour.
In spite of its fragile appearance this viaduct has, up to the present time, served in a most satisfactory manner the purpose for which it was built.—Engineering.
SEA-GOING TORPEDO BOATS.
All investigations of the sea-going qualities of torpedo boats show that while the basin experiments are highly satisfactory, those made at sea prove with equal force the unreliability of these craft when they leave the coast．At the beginning of the Milford Haven operations, the boisterous weather necessitated the postponing of operations, on account of the unfitness of the torpedo boat crews to continue work after the twelve hours of serious fatigue they had already undergone．In the French evolutions, the difficulties of the passage from Bastia to Ajaccio, although not remarkably severe, so unfitted fifteen of the twenty boats that they could take no part in the final attack．In two nights we find recorded collisions which disable boats Nos.52, 61, 63, and 72, and required their return to port for repairs.
Of the twenty-two torpedo boats leaving Toulon a few days before, but six arrived near the enemy, although their commanders displayed admirable energy．One had run aground, and was full of water; another had been sunk by collision; another's engine was seriously injured; and as for the rest, they could not follow.
Of the boats under the command of Admiral Brown de Colstoun, but five remained for service, for the sixth received an accident to her machinery which prevented her taking part in the attack.
During the operations off the Balearic Isles, only one of six boats attacked, and none was able to follow the armorclads, all meeting with circumstances quite unexpected and embarrassing.
With the weather as it existed May 13, the armorclads had the torpedo fleet completely at their mercy, for even if they had not been destroyed by the excellent practice of the Hotchkiss gunners, they would have been of no use, as they could not with safety discharge their torpedoes．In fact, the search lights discovered distinctly that one of the boats, which burned her Coston's signal to announce victory, did not have her torpedo tube open, on account of the heavy sea.
Furthermore, their positions were frequently easily discovered by the immense volume of smoke and flame ejected while going at great speed．This applies as well by night as by day．It was also reported that after the four days' running the speed of the boats was reduced to twelve knots.
With such evidence before us, the seaworthiness of boats of the Nos.63 and 64 type may be seriously questioned．Weyl emphasizes the facts that "practice has shown that boats of No.61 type cannot make headway in a heavy sea, and that it is then often impossible to open their torpedo tubes．On this account they are greatly inferior to ships of moderate tonnage, which can certainly make some progress, fire their torpedoes, and use their artillery in weather when a torpedo boat will be utterly helpless．The torpedo boat abandoned to itself has a very limited field of action."
Du Pin de Saint Andre admits the success of the torpedo boat for harbor and coast work, but wisely concludes that this can prove nothing as to what they may or may not be able to do at sea.
In an article which appeared in theRevue des Deux Mondesin June last, he presented able reasons why the torpedo boats of to-day's type, being destitute of most, if not all, of the requisites of sea-going craft, cannot go to sea, take care of themselves, and remain there prepared to attack an enemy wherever he may be found．Invisibility to an enemy may facilitate attack, but it has to be dearly paid for in diminished safety．Further, the life that must be led in such vessels in time of war would very quickly unfit men for their hazardous duties.
He points out that the effect of such a life upon the bodies and minds of the officers and crew would be most disastrous．The want of exercise alone would be sufficient to unfit them for the demands that service would make upon them．He has intelligently depicted the consequences of such a life, and his reasoning has been indorsed by the reports of French officers who have had experience in the boats in question.
No weapon, no matter how ingenious, is of utility in warfare unless it can be relied upon, and no vessel that is not tenantable can be expected to render any service at sea.
From the evidence before us, we must conclude that the type of torpedo boat under discussion is capable of making sea passages, provided it can communicate frequently with its supply stations and secure the bodily rest so necessary to its crew．But even in a moderate sea it is useless for attack, and in the majority of cases will not be able even to open its impulse tubes．Should it succeed in doing this, the rolling and yawing will render its aim very uncertain.
An experiment conducted against the Richelieu in October last, at Toulon, before Admiral O'Neil, the director-general of the torpedo service, has added its testimony to the uncertainty of the Whitehead torpedo．The Richelieu had been fitted with Bullivant nets, and the trial was made to learn what protection they would afford.
The weather was fair, the sea moderate, and the conditions generally favorable to the torpedo; but the Whitehead missed its mark, although the Richelieu's speed was only three knots．Running at full speed, the torpedo boat, even in this moderate sea, deemed it prudent to keep the launching tube closed, and selected a range of 250 yards for opening it and firing．Just at the moment of discharge a little sea came on board, the boat yawed, the torpedo aim was changed more than 30 deg., and it passed astern without touching its object.
While the Milford Haven operations have taught some valuable lessons, they were conducted under but few of the conditions that are most likely to occur in actual warfare; and had the defense been carried on with an organization and command equal to that of the attack, the Navy's triumph would, perhaps, not have been so easily secured, and the results might have been very different.
May not the apparent deficiencies of the defense have been due to the fact that soldiers instead of sailors are given the control of the harbor and coast defense? Is this right? Ought they not to be organized on a naval basis? This is no new suggestion, but its importance needs emphasis.
These operations, however, convinced at least one deeply interested spectator, Lord Brassey, to the extent of calling attention "to the urgent necessity for the construction of a class of torpedo vessels capable of keeping the sea in company with an armored fleet."
There is no one in Great Britain who takes a greater interest in the progress of the British Navy than Lord Brassey, and we take pleasure in quoting from his letter of August 23 last to theTimes, in which he expressed the following opinion: "The torpedo boats ordered last year from Messrs．Thornycroft and Yarrow are excellent in their class．But their dimensions are not sufficient for sea-going vessels．We must accept a tonnage of not less than 300 tons in order to secure thorough seaworthiness and sufficient coal endurance.
"A beginning has been made in the construction of vessels of the type required．To multiply them with no stinting hand is the paramount question of the day in the department of construction．The boats attached to the Channel fleet at Milford Haven will be most valuable for harbor defense, and for that purpose they are greatly needed．Torpedo boat catchers are not less essential to the efficiency of a fleet．The gunboats attached to the Channel fleet were built for service in the rivers of China．They should be reserved for the work for which they were designed.
"We require for the fleet more fast gunboats of the Curlew and Landrail type．I trust that the next estimates for the Navy will contain an ample provision for building gun vessels of high speed."
As torpedoes must be carried, the next point to which we would call the attention of our readers is the very rapid progress that has been made in the boats designed to carry automatic torpedoes.
A very few years ago the names of Thornycroft and Yarrow were almost alone as builders of a special type of vessel to carry them．To-day, in addition, we have Schichau, White, Herreshoff, Creusot, Thomson, and others, forming a competitive body of high speed torpedo-boat builders who are daily making new and rapid development—almost too rapid, in fact, for the military student to follow.
As new types are designed, additional speed gained, or increased seaworthiness attained, public descriptions quickly follow, and we have ourselves recorded the various advances made so fully that it will be unnecessary to enter into details here.
As late as October, 1885, an able writer said: "The two most celebrated builders of torpedo boats in the world are Thornycroft and Yarrow, in England．Each is capable of producing a first class torpedo boat, from 100 ft．to 130 ft．long, and with 10 ft．to 14 ft．beam, that will steam at the rate of from 18 knots to 22 knots per hour for 370 knots, or at the rate of 10 knots per hour for 3000 miles．A second class torpedo boat is from 40 ft．to 60 ft．long, and with 6 ft．or 8 ft．beam.
The use of these boats is gradually being abandoned in Europe except for use from sea-going ships; but in Europe the harbors are very small, and it has been found that practically every torpedo boat for coast defense must be able to go to sea．The tendency is, therefore, to confinement to the first class boats."
In a paper on "Naval Torpedo Warfare," prepared in January, 1886, for a special committee of the American Senate, by Lieutenant Jaques of the American Navy, we find the following reference to the progress in torpedo boat construction: "The development in torpedo boats has been phenomenal, the last year alone showing an advance from a length of 120 ft．and a speed of 19 knots, which were considered remarkable qualities in a first class boat, to a length of 140 ft．and a speed of 23 knots loaded (carrying 15 tons), and 25 knots light, together with the introduction of novel features of importance.
"Although Messrs．Yarrow and Thornycroft have brought the second class boats to a very high standard in Europe, I believe they will soon be abandoned there even for sea-going ships (very few are now laid down), and that the great development will be in overcoming the disadvantages of delicacy and weakness by increasing their size, giving them greater maneuvering power and safety by the introduction of two engines and twin screws, and steel plate and coal protection against rapid firing ammunition．Yarrow and Co．have already laid down some boats of this character that give promise of developing a speed of from 23 to 25 knots."
In the Russian boat recently built at Glasgow, progress in this direction is also seen in the 148 ft．length, 17 ft．beam, the maneuvering powers and safety element of the twin screws．But while the boat is fitted for the 19 ft．torpedo, a weapon of increased range and heavier explosive charge, it suffers from the impossibility of broadside fire and the disadvantages that Gallwey has named: "The great length of this torpedo, however, makes it a very unhandy weapon for a boat, besides which its extra weight limits the number which can be carried."
While perhaps Messrs．Thomson have been the first to show the performance of a twin screw torpedo boat in England, the one completed in June last by Yarrow for the Japanese government recalls the intelligence that Japan has exercised in the selection of types.
Commencing as far back as nine years ago, the Japanese were probably the first to introduce sea-going boats, and they have been the first power to initiate the armor type, one of which was shipped last summer to be put together in Japan．As before stated, it was built by Messrs．Yarrow and Co., was 166 ft．long, 19 ft．beam, with twin screws, 1 in．steel armor, double engines, with bow and broadside torpedo guns, the latter so arranged as to greatly increase their efficiency.
While the advances are not restricted to the English builders, a glance at the points to which Thornycroft and Yarrow have brought their improvements up to the present time will indicate that their achievements are not only equal to but greater than those of any other builders.
The former has boats under construction 148 ft．long, 15 ft．beam, to make 420 revolutions with 130 lb．of steam, the guaranteed speed being 23 knots on a continuous run of two hours' duration, with a load of 15 tons．They will have triple-expansion or compound direct-acting surface-condensing engines and twin screws, Thornycroft's patent tubular boilers, double rudders, electric search lights, three masts and sails.
While the armaments of the various boats differ, Thornycroft is prepared to fit the launching tubes with either air or powder impulse, to mount the tubes forward or on deck, and also the fittings for machine and rapid firing guns.
Yarrow and Co．have contracted for boats varying in length from 117 ft．to 166 ft., with fittings and armament as may be required．They have obtained excellent results in their last English boat of the Admiralty type．They are, in fact, prepared to guarantee a speed of 23 knots in a length of 125 ft．and 25 knots in a length of 140 ft., carrying in both causes a mean load corresponding to fuel and armament of 10 tons.
And so the progress goes on, but it will not stop here; it has already incited a marked development in ship construction, and the endeavors to withstand torpedo attack have improved the defense against gun fire also.
In quoting a German opinion on the development of the Russian torpedo fleet, Charmes refers to the type which will, no doubt, be most successful upon the sea, namely, the torpedo cruisers, and it is to this type, more than for any other, that we may expect torpedo boats to be adapted．Already, writers have dropped the phrase "torpedo boats" for "torpedo vessels."—Engineering.
FIRING TRIAL OF THE 110½ TON B.L．ELSWICK GUN.
The firing trial of the first new 110½ ton breech loading gun approved for H.M.'s ships Benbow, Renown, and Sanspareil was commenced recently at the Woolwich proof butts, under the direction of Colonel Maitland, the superintendent of the Royal Gun Factories．We give herewith a section showing the construction of this gun (videFig.8)．It very nearly corresponds to the section given of it when designed in 1884, in a paper read by Colonel Maitland at the United Service Institution, of which we gave a long account in theEngineerof June 27, 1884.
The following figures are authoritative: Length over all, 524 in.; length of bore, 487.5 in．(30 calibers)．The breech engages in the breech piece, leaving the A tube with its full strength for tangential strain (videFig.)．The A tube is in a single piece instead of two lengths, as in the case of the Italia guns．It is supplied to Elswick from Whitworth's works, one of the few in England where such a tube could be made．There are four layers of metal hoops over the breech．Copper and bronze are used to give longitudinal strength．The obturation is a modification of the De Bange system, proposed by Vavasseur.
THE NEW 110½ TON ELSWICK GUNS FOR H.M.S．BENBOW.
The maximum firing charge is 900 lb．of cocoa powder．The projectile weighs 1,800 lb．The estimated muzzle velocity is 2,216 ft．per second．The capacity of the chamber is 28,610 cubic inches, and that of the bore 112,595 cubic inches．The estimated total energy is 61,200 ft．tons．It will be a few days probably before the full powers of the gun are tested, but the above are confidently expected to be attained, judging from the results with the 100 ton guns supplied to Italy．On January 7 last we gave those of the new Krupp 119 ton gun．It had fired a projectile with a velocity of almost 1,900 ft．with a charge of less than 864.67 lb., with moderate pressure．The estimated maximum for this gun was a velocity of 2,017 ft．with a projectile weighing 1,632 lb., giving a total energy of 46,061 ft．tons, or 13,000 ft．tons less than the Elswick gun, comparing the estimated results.
The proof of the Elswick gun is mounted on a carriage turned out by the Royal Carriage Department, under Colonel Close．This carriage is made on bogies so as to run on rails passing easily round curves of 50 ft．radius．The gun is fired on an inclined length of rails, the recoil presses of the carriage first receiving the shock and reducing the recoil．The carriage is made to lift into the government barge, so as to go easily to Shoeburyness or elsewhere．It can be altered so as to provide for turning, and it allows the piece to be fired at angles of elevation up to 24 deg．The cheeks of the carriage are made to open and close, so as to take the 12 in．gun and larger pieces．The steel castings for it are supplied from the Stanners Close Steel Works.
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