Chapter VIII: MISCELLANEOUS.--Bayle's New Lamp Chimney.--With engraving (3)

From the Brighton to the South-Western Railway is but a step; but here a totally different practice obtains to that adopted on most lines, all the passenger engines having outside cylinders, where they are more exposed to damage in case of accident, and, from being less protected, there is more condensation of steam, while the width between the cylinders tends to make an unsteady running engine at high speeds, unless the balancing is perfect; but the costly crank axle, with its risk of fracture, is avoided, and the center of gravity of the boiler may be consequently lowered, while larger cylinders may be employed. On the other hand, inside cylinders are well secured, protected, and kept hot in the smoke-box, thus minimizing the condensation of steam. The steam ports are short, and the engine runs steadier at high speeds, while with Joy's valve gear much larger cylinders can be got in than with the link motion. Thus modern improvements have minimized the advantages of the outside class.

The passenger engines for the fast traffic are of two types, the six-wheel engines with 7 ft. coupled wheels, and the new bogie engines which are being built to replace them. The former have 17 in. cylinders with 22 in. stroke, and a pair of coupled wheels 7 ft. in diameter, the leading wheels being 4 ft. diameter, and the wheel base 14 ft. 3 in. The grate area is 16.1 square feet, and the heating surface 1,141 square feet. The total weight in working order is 33 tons. The chief peculiarity of this type of engine consists in the boiler, which is fitted with a combustion chamber stocked with perforated bricks, the tubes being only 5 ft. 4 in. long. These engines are very expensive to build and maintain, owing to the complicated character of the boiler and fire-box, but as a coal burning engine there is no doubt the class was very efficient, but no more are being built, and a new type has been substituted. This is an outside cylinder bogie engine, with cylinders 18½ in. diameter and 26 in. stroke; the driving and trailing coupled wheels are 6 ft. 6 in. diameter, and the bogie wheels 3 ft. 3 in. The wheel base to the center of the bogie pin is 18 ft. 6 in.; the heating surface is, in the tubes, 1,112; fire box, 104; total, 1,216 sq. ft. The weight of the engine in working order is 42 tons.

The Midland Railway route to the North is distinguished by the heavy nature of its gradients; between Settle and Carlisle, running through the Cumberland hills, attaining a height of 1,170 ft. above sea level, the highest point of any express route in the kingdom; and to work heavy fast traffic over such a line necessitates the employment of coupled engines. The standard express locomotive of this company has inside cylinders 18 in. in diameter and 26 in. stroke. The coupled wheels are 6 ft. 9 in. diameter, and the leading wheels 4 ft. 3 in., the total wheel base being 16 ft. 6 in., and the tractive force 104 lb. for each lb. of mean cylinder pressure. The boiler is of best Yorkshire iron, 10 ft. 4 in. long and 4 ft. 1 in. diameter. The grate area is 17.5 square feet, and the heating surface is, in the tubes, 1,096; fire-box, 110; total, 1,206. There are double frames to give outside bearings to the leading axle, as in the Great Western engine, and the engine is fitted with a steam brake. The weight in full working order is--leading wheels, 12 tons 2 cwt.; driving wheels, 15 tons; trailing wheels, 11 tons 6 cwt.; total, 38 tons 8 cwt. The tender weighs 26 tons 2 cwt., and holds 3,300 gallons of water and 5 tons of coal. Latterly a fine type of bogie express engine has been introduced, with inside cylinders 18 in. diameter and 26 in. stroke, and four coupled driving wheels 7 ft. diameter. The total wheel base to the center of the bogie pin is 18 ft. 6 in. The grate area is 17.5 square feet, and the heating surface is, in tubes, 1,203 square feet, and fire-box, 110; total, 1,313; and the engine weighs 42 tons in working order. These engines take fourteen coaches, or a gross load of 222 tons, at 50 miles an hour over gradients of 1 in 120 to 1 in 130, with a consumption of 28 lb. of coal per mile. The London, Chatham, and Dover Company has also some fine engines of a similar type. They have inside cylinders 17½ in. diameter and 26 in. stroke; the coupled wheels are 6 ft. 6 in. diameter, and the bogie wheels 3 ft. 6 in., the wheel base to the center of the bogie pin being 18 ft. 2 in. The boiler is 10 ft. 2 in. long and 4 ft. 2 in. diameter, the grate area is 16.3 square feet, and the heating surface is, in the tubes, 962 square feet; fire-box, 107 square feet; total, 1,069. The boiler pressure is 140 lb., and the tractive force per lb. of steam in the cylinder 102 lb. The weight in full working order is, on the bogie wheels, 15 tons 10 cwt.; driving wheels, 13 tons 10 cwt.; trailing wheels, 13 tons; total, 42 tons.

Mr. Worsdell has lately designed for the Great Eastern Railway a fine type of coupled express engine, which deserves mention. It has inside cylinders 18 in. diameter and 24 in. stroke, with coupled wheels 7 ft. diameter and leading wheels 4 ft. diameter, the latter being fitted with a radial axle on a somewhat similar plan to that previously described as adopted by Mr. Webb for the new North-Western engines; the frames are single, with inside bearings to all the wheels, and Joy's valve gear is used. The boiler pressure is 140 lb., and the tractive power per lb. of mean cylinder pressure 92 lb. The total wheel base is 17 ft. 6 in. The boiler, which is fed by two injectors, is of steel, 11 ft. 5 in. long and 4 ft. 2 in. diameter. The grate area is 17.3 square feet, and the heating surface is, in the tubes, 1,083; fire-box, 117; total, 1,200 sq. ft. The weight in working order is, on the leading wheels, 12 tons 19 cwt.; driving wheels, 15 tons; trailing wheels, 13 tons 4 cwt.; total, 41 tons 3 cwt. These engines burn 27 lb. of coal per train mile with trains averaging thirteen coaches. It has been seen that the Cheshire lines express between Liverpool and Manchester is one of the fastest in England, and the Manchester, Sheffield, and Lincolnshire Railway Company, who works the trains, has just introduced a new class of engine specially for this and other express trains on the line. The cylinders are outside, 17½ in. diameter and 26 in. stroke, with single driving wheels 7 ft. 5 in. diameter, the leading and trailing wheels being 3 ft. 8 in. diameter. The total wheel base is 15 ft. 9 in., and the frames are double, giving outside bearings to the leading and trailing axles, and inside bearings to the driving axle. The boiler is 11 ft. 6 in. long and 3 ft. 11 in. diameter, and the grate area is 17 square feet. The heating surface is in the tubes 1,057 square feet; fire-box, 87 square feet; total, 1,144 square feet. The tractive force per pound of mean cylinder pressure is 88.4 lb. The weight in full working order is, on the leading wheels, 11 tons 3 cwt.; driving wheels, 17 tons 11 cwt.; trailing wheels, 11 tons 18 cwt.; total, 40 tons 12 cwt. This engine is remarkable for the great weight thrown on the driving wheels, and its cylinder power is great in proportion to its adhesion, thus allowing the steam to be worked at a high rate of expansion, which is most favorable to the economical consumption of fuel. There are numerous fine engines running on other lines, such as the new bogie locomotives on the North-Eastern and Lancashire and Yorkshire railways, and the coupled express engines on the Caledonian; but those already described represent fairly the lending features of modern practice, and the author will now notice briefly the two other classes of engines--tank passenger engines for suburban and local traffic and goods engines. The Brighton tank passenger engine is a good example of the former class; it has inside cylinders 17 in. diameter and 24 in. stroke. The two coupled wheels under the barrel of the boiler are 5 ft. 6 in. diameter, and the trailing wheels 4 ft. 6 in.; there are single frames with inside bearings to all the axles. The boiler pressure is 140 lb., and the tractive force per pound of mean cylinder pressure 106 lb.; the total wheel base is 14 ft. 6 in. The boiler is 10 ft. 2 in. long and 4 ft. 4 in. diameter, and the heating surface is in the tubes, 858 square feet; fire-box, 90 square feet; total, 948 square feet. The engine is furnished with wing tanks holding 860 gallons of water, and carries 30 cwt. of coal. The weight in working order is 38 tons. These engines have taken a maximum load of twenty-five coaches between London and Brighton, but are mainly employed in working the suburban and branch line traffic; their average consumption of coal is 23.5 lb. per mile, with trains averaging about ten coaches.

Another example is Mr. Webb's tank engine on the North-Western Railway, which presents a contrast to the foregoing. It has inside cylinders 17 in. diameter and 20 in. stroke, coupled wheels 4 ft. 6 in. diameter, and a tractive power per lb. of mean cylinder pressure of 107 lb.; the wheel base is 14 ft. 6 in. with a radial box to the leading axle; the heating surface is in the tubes, 887; fire-box, 84; total, 971 square feet; the weight in working order is 35 tons 15 cwt. The engine is fitted with Webb's hydraulic brake, and steel, manufactured at Crewe, is largely used in its construction. The consumption of coal-working fast passenger trains has been 28½ lb. per mile. There are many other types, such as the ten wheel bogie tank engines of the London, Tilbury, and Southend and South-Western railways; the saddle tank bogie engines, working the broad gauge trains on the Great Western Railway, west of Newton; and the familiar class working the Metropolitan and North London traffic. But the same principle is adopted in nearly all--a flexible wheel base to enable them to traverse sharp curves, small driving wheels coupled for adhesion, and wing or saddle tanks to take the water. One notable exception is, however, the little six wheel all-coupled engines weighing only 24 tons, which work the South London traffic, burning 24¼ lb. of coal per mile, with an average load of eleven coaches.

Goods engines on all lines do not vary much. As a rule they are six wheel all-coupled engines, with generally 5 ft. wheels, and cylinders varying between 17 in. and 18 in. diameter and 24 in. to 26 in. stroke; the grate area is about 17 square feet, and the total heating surface from 1,000 to 1,200 sq. ft.; the average weight in full working order varies from 30 to 38 tons. One noteworthy exception occurs, however, on the Great Eastern Railway, where a type of goods engine with a pony truck in front has been introduced. The cylinders are outside 19 in. diameter and 26 in. stroke, there are six coupled wheels 4 ft. 10 in. diameter, and the pony truck wheels are 2 ft. 10 in. diameter; the total wheel wheel base is 23 ft. 2 in., but there are no flanges on the driving wheels. The boiler is 11 ft. 5 in. long and 4 ft. 5 in. diameter, the boiler pressure is 140 lb., and the tractive force per lb. of mean cylinder pressure 162 lb.; the grate area is 18.3 square feet, and the heating surface is in the tubes, 1,334 square feet; fire-box, 122 square feet; total, 1,456 square feet.

The weight in working order is on the pony truck, 8 tons 10 cwt.; leading coupled, 12 tons 8 cwt.; driving coupled, 13 tons 5 cwt.; trailing coupled, 12 tons 15 cwt.; total, 47 tons.

The tender weighs 28 tons in full working order. These engines take 40 loaded coal trucks or sixty empty ones, and burn 52 lb. of coal per train mile, the worst gradient being 1 in 176. A notice of goods engines would not be complete without alluding to a steep gradient locomotive, and a good example is the engine which works the Redheugh Bank on the North-Eastern Railway. This incline is 1,040 yards long, and rises for 570 yards 1 in 33, then for 260 yards 1 in 21.7, for 200 yards 1 in 25, and finally for 110 yards 1 in 27. The engine, which is an all-coupled six wheel tank engine, weighs 48½ tons in working order, it has cylinders 18 in. diameter and 24 in. stroke, and 4 ft. wheels, the boiler pressure is 160 lb., and the tractive force per lb. of mean steam pressure in the cylinders is 162 lb. This engine will take up the incline twenty-six coal wagons, or a gross load of 218 tons, which is a very good duty indeed.

Having now passed in review the general types of engines adopted in modern English practice, the author would briefly draw attention to some points of design and some improvements effected in late years. And first, as to the question of single or coupled engines, there is a great diversity of opinion. Mr. Stirling conducts his traffic at a higher rate of speed, and certainly with equal punctuality, with his magnificent single 8 ft. engines, as Mr. Webb on the North-Western with coupled engines, and the economy of fuel of the former class over the latter is very remarkable; this is, no doubt, owing, as has been previously pointed out, to their ample cylinder power, which permits of the steam being worked at a high rate of expansion. There is no doubt that if single engines can take the load they will do so more freely and at a less cost than coupled engines, burning on the average 2 lb. of coal per mile less with similar trains. With, regard to loads, it is a question whether any express train should be made up with more than twenty-five coaches. The Great Northern engine will take twenty-six and keep time, and the Brighton single engine has taken the five P.M. express from London Bridge to Brighton, consisting of twenty-two coaches, at a speed of forty-five miles per hour. Of course where heavy gradients have to be surmounted, such as those on the Midland route to Scotland, coupled engines are a necessity. Single engines are said to slip more than coupled; thus an 8 ft. single Great Northern engine running down the incline from Potter's Bar to Wood Green with twelve coaches at the rate of sixty miles an hour was found to be making 242 revolutions per mile instead of 210; and in an experiment tried on the Midland Railway it was found that a coupled engine with ten coaches at fifty miles an hour made seventeen extra revolutions a mile, but when the side rods were removed it made forty-three. The Great Western, Great Northern, and Brighton mainly employ single engines for their fast traffic; and the Manchester, Sheffield, and Lincolnshire have now adopted the single type in preference to the coupled for their express trains; while the North-Western, Midland, South-Western, and Chatham adopted the coupled type. One noticeable feature in modern practice is the increased height of the center line of boiler; formerly it was the great aim to keep this low, and numerous schemes to this effect were propounded, but now it has become generally recognized that a high pitched engine will travel as steadily and more safely round a curve--given a good road--than a low pitched one; and thus while in 1850 the average height of the center line of boilers varied between 5 ft. 3 in. and 6 ft. 3 in., now in the latest designs it lies between 7 ft. and 7 ft. 6 in. Single frames are very generally adopted, but double frames and outside bearings to the leading and trailing wheels, as in the Great Western engines, give great steadiness in running, and this class has also double bearings to the driving wheels, thus entailing greater security in case of the facture of a crank axle. The general adoption of cabs on the foot-plate for the men is another improvement of late introduction, although at first not universally appreciated by those for whose comfort it was designed--"I felt as if I was in my coffin," said an old driver when asked how he liked the new shelter. Mild steel fire-boxes, which have been employed in America, are not in favor here, copper being universally used; they have been tried on the Caledonian, Great Southern and Western, North London, and North-Western, and were found not to succeed. Brake blocks of cast iron have now generally superseded wood; steel is being more and more used, especially on the North Western. There is less use of brasswork for domes and fittings, although it is claimed for brass that it looks brighter and can easily be kept clean. There is greater simplicity of design generally, and the universal substitution of coal as coke for fuel, with its consequent economy; and last, but not least, the adoption of standard types of engines, are among the changes which have taken place in locomotive practice during the past quarter of a century.

Having now reviewed, as far as the limits of this paper will allow, the locomotive practice of the present day, the author would in conclusion draw attention to what may possibly be one course of locomotive development in the future. Time is money, and it may be in the coming years that a demand will arise for faster means of transit than that which we possess at present. How can we meet it? With our railways laid out with the curves and gradients existing, and with our national gauge, and our present type of locomotive, no great advance in speed is very probable; the mean speed of express trains is about fifty miles an hour, and to take an average train of 200 tons weight at this speed over a level line requires between 650 and 700 effective horse-power, within the compass of the best engines of the present day. But if instead of fifty miles an hour seventy is required, an entirely different state of things obtains. Taking a train of 100 tons, with engine and tender weighing 75 tons, or 175 tons gross, the first question to determine will be the train resistance, and with reference to this we much want careful experiments on the subject, like those which Sir Daniel Gooch made in 1848, on the Bristol and Exeter Railway, which are even now the standard authority; the general use of oil axle-boxes and long bogie coaches, irrespective of other improvements, would render this course desirable. With regard to the former, they appear to run with less friction, but are heavier to start, oil boxes in some experiments made on the South-Western Railway giving a resistance of 2.5 lb. per ton, while grease boxes ranged from 6 lb. to 9 lb. per ton. Again, the long and heavy bogie Pullman and other coaches have the reputation among drivers, rightly or wrongly, of being hard to pull. The resistance of an express train on the Great Western Railway at seventy-five miles an hour was 42 lb. per ton, and taking 40 lb. per ton for seventy miles an hour would give a total resistance on the level of 7,000 lb., corresponding to 1,400 horse-power--about double the average duty of an express engine of the present day. The weight on the driving wheels required would be 18¾ tons, allowing one-sixth for adhesion, about the same as that on the driving axle of the Bristol and Exeter old bogie engines. Allowing 2½ lb. of coal per horse-power per hour would give a total combustion of 3,500 lb. per hour and to burn this even at the maximum economic rate of 85 lb. per square foot of grate per hour would require a grate area of 41 square feet, and about 2,800 square feet of heating surface. Unless a most exceptional construction combined with small wheels is adopted, it appears almost impossible to get this amount on the ordinary gauge. It is true the Wootten locomotives on the Philadelphia and Reading Railway have fire-boxes with a grate area of as much as 76 square feet, but these boxes extend clean over the wheels, and the heating surface in the tubes is only 982 square feet; but although these engines run at a speed of forty-two miles an hour, they are hardly the type to be adopted for such a service as is being considered. On the broad gauge, however, such an engine could easily be designed on the lines now recognized as being essential for express engines without introducing any exceptional construction, and there appears but little doubt that were Brunei's magnificent gauge the national one, competition would have introduced a higher rate of speed between London and our great towns than that which obtains at present.

The whole question of the future introduction of trunk lines, exclusively for fast passenger traffic, is fraught with the highest interest, but it would be foreign to the subject matter of this paper to enter more fully on it, the author merely desiring to state his opinion that if the future trade and wealth of our country require their construction, and if a very high rate of speed much above our present is to be attained, their gauge will have to be seriously considered and settled, not by the reasons which caused the adoption of the present gauge, but by the power required to carry on the traffic--in fact, to adapt the rail to the engine, and not, as at present, the engine to the rail. High speed requires great power, and great power can only be obtained by ample fire-grate area, which for a steady running engine means a broad gauge. The Gauge Commissioners of 1846 in their report esteemed the importance of the highest speed on express trains for the accommodation of a comparatively small number of persons, however desirable that may be to them, as of far less moment than affording increased convenience to the general commercial traffic of the country. The commercial traffic of England has grown and prospered under our present system, and if its ever increasing importance demands high speed passenger lines, we may rest assured that the ingenuity of man, to which it is impossible to assign limits, will satisfactorily solve the problem.

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SCREW STEAM COLLIER FROSTBURG.

Our diagram shows the screw steam collier Frostburg, built by Henry H. Gorringe (the American Shipbuilding Co.), Philadelphia, Pa. Length, 210 ft. Beam, 33 ft. Depth, 17 ft, Register tonnage, 533. Carrying capacity on 14ft., 1,100 tons, and 100 tons coal in bunker. Cubical contents of cargo space, 55,168 cub. ft. Carrying capacity on 16 feet draught, 1,440 tons. Engines, compound surface condensing. High pressure 26 in. diameter, low pressure 48 in. diameter, stroke 36 in. Two boilers, each 13 ft. diameter. 10 ft. long, and one auxiliary 5 ft. diameter and 10 ft. high. 100 lb. working pressure. Sea speed with full cargo, 11 knots.

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A thirteen year old girl, who is perfect in other ways, but who has simply little blue spots that puff out slightly where her eyes should be, is said to be living at Amherst, Portage County, Wisconsin.

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DESTRUCTION OF THE TARDES VIADUCT.

The railroad from Montlucon to Eygurande, which is being constructed by the state engineers, crosses the valley of the Tardes in the environs of Evaux (Creuse).

At the spot selected for the establishment of the viaduct the gauge is deep and steep. The line passes at 300 feet above the river, and the total length of the metallic superstructure had to be 822 feet. To support this there was built upon the right bank a pier 158 feet in height, and, upon the left, another one of 196 feet. The superstructure had been completed, and a portion of it had already been swung into position, when a violent, gale occurred and blew it to the bottom of the gorge. At the time of the accident the superstructure projected 174 feet beyond the pier on the right bank, and had to advance but 121 feet to reach the 33 foot scaffolding that had been established upon the other pier.

It blows often and violently in this region. For example, a gale on the 20th of February, 1879, caused great damage, and, among other things, blew the rear cars of a hay train from the top of the Louvoux viaduct to the Bouble.

The superstructure of the Tardes viaduct had already withstood the tempest of the 23d and the 24th of January, 1884, and neither any alteration in its direction nor any change in the parts that held it upon the pile could be perceived. But on the night of January 26-27 the storm doubled in violence, and the work was precipitated into the ravine. No one was witness of the fall, and the noise was perceived only by the occupants of the mill located below the viaduct.

The workmen of the enterprise, who lived about 325 feet above this mill and about 650 feet from the south abutment, heard nothing of it, the wind having carried the noise in an opposite direction. It was not until morning that they learned of the destruction of their work and the extent of the disaster.

One hundred and sixty-nine feet of the superstructure, weighing 450 tons, had been precipitated from a height of nearly 200 feet and been broken up on the rock at 45 feet from the axis of the pier. The breakage had occurred upon the abutment, and the part 195 feet in length that remained in position in the cutting was strongly wedged between walls of rock, which had kept this portion in place and prevented its following the other into the ravine.

Upon the pier there remained a few broken pieces and a portion of the apparatus used in swinging the superstructure into place.

Below, in the debris of the superstructure, the up-stream girder lay upon the down-stream one. The annexed engraving shows the state of things after the disaster.

Several opinions have been expressed in regard to the cause of the fall. According to one of these, the superstructure was suddenly wrenched from its bearings upon the pier, and was horizontally displaced by an impulse such that, when it touched the masonry, its up-stream girder struck the center of the pier, upon which it divided, while the down-stream one was already in space. The fall would have afterward continued without the superstructure meeting the face of the pier.

Upon taking as a basis the horizontal displacement of the superstructure, which was 45 meters to the right of the pier, and upon combining the horizontal stress that produced it with that of the loads, the stress exerted upon the body may he deduced. But this hypothesis seems to us scarcely tenable, especially by reason of the great stress that it would have taken to lift the superstructure. On another hand, it was possible for the latter to slide over one edge of the pier, and this explains the horizontal distance of 45 feet by which its center of gravity was displaced. It is probable, moreover, that the superstructure, before going over, moved laterally upon its temporary supports.

The girders were, in fact, resting upon rollers, and the roller apparatus themselves were renting upon wedges, and there was no anchorage to prevent a transverse sliding.

Under the prolonged thrust of a very high wind, the superstructure, by reason of its considerable projection, must have begun to swing like a pendulum. These oscillations acquired sufficient amplitude to cause the superstructure to gradually move upon its rollers until the latter no longer bore beneath the webs. The flanges therefore finally bent upward where they rested upon the rollers, through the action of the weight which they had to support, and the entire superstructure slid off into space.

An examination of the bent pieces seems to give great value to this hypothesis.--_Le Genie Civil_.

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JOY'S REVERSING AND EXPANSION VALVE GEAR.

[Footnote: A paper read before the Mechanical Section of the British Association, at Montreal, August, 1884.]

Four years ago, in August, 1880, a paper was read on this subject before the Annual Summer Meeting of the Mechanical Engineers' Society of Great Britain, then held in Barrow-in-Furness, describing this valve motion and its functions, which was then comparatively new. It was, however, illustrated by its application to a large express goods (freight) engine, built by the London and North-Western Railway Company (England) specially to test the advantages and the endurance of the gear. This engine had cylinders of 18 inches in diameter and 24 inch stroke, and six wheels coupled 5 feet 1 inch diameter, and was designed by Mr. Webb, the Company's chief engineer, for their heavy fast goods traffic on the main line. The engine has been running this class of traffic ever since. In January, 1884, it was passed through the repair shops for a general overhauling, when it was found that the valve motion was in such good condition as to be put back on the engine without any repairs.

The main object of this present paper is to deal with the advantages of the valve gear and its application to various classes of engines both on land and at sea, and with the results of such applications, rather than treating it as a novelty, to give an exhaustive description of its construction and functions, which was done in the paper above referred to. A very short description of its action and main features will, however, be necessary to the completeness of the paper, and as a basis from which the improved results to be recorded should necessarily be shown to spring.

The essential feature of this valve gear is that movement for the valve is produced by a combination of two motions at right angles to each other; and by the various proportions in which these are combined, and by the positions in which the moving parts are set with regard to each other, it gives both the reversal of motion and the various degrees of expansion required. Eccentrics are entirely dispensed with and the time-honored link gear abandoned, the motion is taken direct from the connecting rod, and by utilizing independently the backward and forward action of the rod, due to the reciprocation of the piston, and combining this with the vibrating action of the rod, a movement results which is suitable to work the valves of engines, allowing the use of any proportions of lap and lead desired, and giving an almost mathematically correct "cut-off" for both sides of the piston and for all points of expansion intermediately, as well as a much quicker action at the points of "cut-off" and "release" than is given by a link gear.

The machinery for accomplishing this is both less costly and less complicated than the ordinary link motion, and is shown in elevation on cut, which is a view of the complete motion as on the first London and North-Western locomotive. Here E is the main valve lever, pinned at D to a link, B, one end of which is fastened to the connecting rod at A, and the other end maintained in about the vertical by the radius rod, C, which is fixed at the point, C¹. The center or fulcrum, F, of the lever, E, partaking of the vibrating movement of the connecting rod at the point, A, is carried in a curved slide, J, the radius of which is equal to the length of the link, G, and the center of which is fixed to be concentric with the fulcrum, F, of the lever when the piston is at either extreme end of its stroke. From the upper end of the lever, E, the motion is carried direct to the valve by the rod, G. It will be evident thus that by one revolution of the crank the lower end of the lever, E, will have imparted to it two different movements, one along the longer axis of the ellipse, traveled by the point, A, and one through its minor axis up and down, these movements differing as to time, and corresponding with the part of the movement of the valve required for lap and lead, and that part constituting the port opening for admission of steam.

The former of these is constant and unalterable, the latter is controllable by the angle at which the curved slide, J, may be set with the vertical.

It will further be evident that if the lever, E, were pinned direct to the connecting rod at the point, A, which passes through a practically true ellipse, it would vibrate its fulcrum, F, unequally on either side of the center of the curved slide, J, by the amount of the versed sine of the arc of the lever, E, from F D; it is to correct this error that the lever, E, is pinned at the point, D, to a parallel motion formed by the parts, B and C. The point, D, performing a figure which is equal to an ellipse, with the error to be eliminated added, so neutralizing its effect on the motion of the fulcrum, F.

The "lap" and "lead" are opened by the action of the valve lever acting as a lever, and the port opening is given by the incline of the curved slide in which the center of that lever slides, and the amount of this opening depends upon the angle given to that incline. When these two actions are in unison, the motion of the valve is very rapid, and this occurs when the steam is being admitted. Then follows a period of opposition of these motions, during which time the valve pauses momentarily, this corresponding to the time when the port is fully open. Further periods of unison follow, at which time the sharp "cut-off" is obtained.

The "compression" resulting with this gear is also reduced to a minimum, owing to the peculiar movement given to the valves (_i. e._, the series of accelerations and retardations referred to), as, while the "lead" is obtained later and quicker, the port is also shut for "compression" later and quicker, doing away with the necessity for a special expansion valve, with its complicated and expensive machinery, and allowing the main valve to be used for expansion, as the "compression" is not of an injurious amount, even with a "cut-off" reduced to 15 per cent., or about 1/6 of the stroke.

Thus, so far as the distribution of the steam and its treatment in the cylinder is concerned, a marked advantage is shown in favor of this valve gear. But next in its favor, as before said, is that the above advantages are not gained at the cost of added complication of parts or increased cost of machinery, but the reverse, as this gear can be built at a less cost than link gear, varying according to the circumstances, but reaching as high as a saving of 25 per cent., or, if it be compared with a link gear supplemented by the usual special expansion valve and gear as employed on marine engines, then the total saving is fully 50 per cent., and an equally good result is obtained as to the distribution and subsequent treatment of the steam.

After accuracy of result and reduction in cost may rank saving room and the advantages arising therefrom (though for steamships perhaps this should have come first). Taking locomotives of the inside cylinder type, which is the general form in use in England and the continent of Europe, by clearing away the eccentrics and valves from the middle of the engine, much larger cylinders may be introduced and a higher rate of expansion employed, and this is being done. Also room is left for increasing the length and wearing surfaces of all the main bearings with even less crowding than is now the case with engines with the smaller cylinders.

But this advantage of saving room comes much more prominently forward in marine engines, especially in war ships, where every inch of room saved is valuable; and in the new type of triple-cylinder engines now coming so much into vogue in the mercantile marine, whether those engines be only the ordinary three-cylinder engines with double expansion, or the newer, triple expansion engine, expanding the steam consecutively through three cylinders--the form of marine engine which promises to come into use wherever high-class work and economy are required. On this system, by placing all the valve chests in front of the cylinders instead of between them, or in a line with them, sufficient room is saved to get the new-type three-cylinder engine into the space occupied by the old form of two-cylinder engine.

Besides these prominent advantages there are others which, though of minor importance, are still necessary to the practical and permanent success of any new mechanical arrangement, such as the accessibility of all the working parts while in motion, for examination and oiling; the ease with which any part or the whole can be stripped and cleaned, or pinned up out of the way in case of break down or accident, or got at and dismantled for ordinary repair; the ease with which the whole may be handled, started, reversed, or set at any point of expansion--all these being recommendations to enlist the care and attention of the engineers in charge by lightening their duties and rendering the engines easy to work.

With those advantages it is perhaps not surprising that this valve gear has been very considerably adopted for many classes of steam engines, especially where a high result has been required, with economy of space, and a minimum of complication.

Having crucially tested the original engine on the London and North-Western Railway, Mr. Webb proceeded to build others similar, and on his bringing out his Compound Express Engine--notably the most advanced step in locomotive design of the present day--he adopted this valve gear throughout. There are now a number of these engines running some of the fastest trains on the London and North-Western Railway, with the most satisfactory results.

Following these, others of the leading railways took up the system, and prominently among these Mr. Worsdell, of the Great Eastern Railway, built a number of large express engines for his fast and heavy traffic, and is now building a number of others similar as to the valve gear for his suburban traffic, which is specially heavy. Also the Lancashire and Yorkshire and the Midland and others of the chief railways are employing the system specially for large express engines; the Midland engines having cylinders of 19 inches diameter by 26 inches stroke, and four coupled wheels of 7 feet diameter. A number of the above-named engines have run large mileages, in many cases already exceeding 100,000 miles per engine. For other countries also a number of locomotive engines have been built or contracted for--both of inside and outside cylinder types--making a total of nearly 800 locomotives built and building, many of them being of special design and large size, up to 20 inches and 21 inches diameter of cylinder.

In all these the absence of wire-drawing may be specially noted by the full line at the top of the diagram, showing the admission of steam--this fullness arising from the rapid and full opening of the port for admission.

Passing now to the other great type of engines, those covered under the general designation of marine engines, this gear has been applied to nearly 40,000 H.P. indicated, built and building, and to all classes and sizes, from the launch engine with cylinders 8 inches by 9 inches, running at 600 to 700 revolutions per minute, up to engines for the largest class of war ships, such as her Britannic Majesty's steel cruiser Amphion, of 5,000 H.P., with cylinders in duplicate of 46 inches and 86 inches diameter, and 3 feet 3 inches stroke, running 100 revolutions per minute. An examination of the indicator diagrams taken from these engines shows that no wire-drawing takes place, and that, though the expansion is carried to a point beyond the ordinary requirements, the compression is but slightly increased. In all the diagrams taken from this valve motion there is seen the clear, full upper line showing an abundant admission of steam without any wire-drawing, and also the distinctly marked points where "cut-off" or "suppression" and where "release" takes place, showing the rapid action of the valves at those points.

It is well known to engineers that to obtain the maximum advantage out of compounding, it is necessary to cut off in the low pressure cylinder at a point corresponding to the relation between the low and the high, and that point should be unaltered, whereas the point of cut-off in the high may at the same time be varied to suit the work to be done.

In an ordinary link motion engine (where both links are connected to the same weigh shaft), when linking up the high pressure cylinder to cut-off short, the same change is necessarily made in the low. By the use of the Joy gear, cut-off valves may be fitted to both cylinders, that for the low pressure being fixed at the constant position required by the proportion of the cylinders, while that on the high is adjustable; of course, in this case, the position of the quadrants must be only changed for reversing. In arranging the independent cut-off on the Joy gear, it is only necessary to increase the length of the vibrating link beyond the point of attachment for the main valve spindle connection to obtain a point from which motion may be taken to actuate the cut-off valve; even then the cost of the Joy gear for both cylinders is but little more than for a single set of link gear.

This arrangement gives an absolutely perfect distribution of steam for compounding, also equalizes the power developed by both cylinders, and is far more simple and inexpensive than any other gear in existence.

* * * * *

THE STEAM BELL.

The secondary railways in rural districts in Austria having no gates or bars at the level crossings, or guards at such points, but being open like tramways, special precautions are required to avoid accidents, and the public has to be warned of the approach of the train from a sufficient distance. This is done by ringing bells preferably to sounding whistles, as these are more likely to startle horses. The steam bell shown by our illustrations has been adopted for this purpose on the Austrian lines, and is a simple contrivance. It consists of a cylindrical chamber, a, ending in a narrower tube, c, which forms the seating for a flap valve, d, to which the hammer or clapper, e, is fixed. Steam is admitted through a small pipe, b, at the bottom, and after a certain interval attains sufficient pressure to lift the valve. The opening being large compared with the pipe, b, steam escapes more rapidly than it arrives through the small orifice; the pressure falls, and the valve drops down and causes the hammer to strike a bell surrounding the cylinder. The valve is provided with an internal collar as shown, so that it has to rise for the width of this before the steam is let out, and thus determines the swing of the clapper and the force of the blow. To intensify the latter and multiply the number of blows, the clapper spring is prolonged over the fulcrum and bent back so as to form a spring, which is tightened by the lifting of the flap, and sends the clapper down on the bell with increased force. The hinge of the flap does not require any lubrication besides what it gets through the steam. The bell is fixed upon the roof of the driver's cab, so that the steam does not interfere with his lookout, and fastened by three bolts or screws. The diameter of the steam-pipe is from ¼ to ½ inch according to the size of the bell, and the distance of the clapper from the bell is a little less than the diameter of the corresponding cock. The steam cock is perforated as shown by the illustration to drain the pipe when shut, and a small hole, b¹, in the bell cylinder drains the latter. The steam-pipe is made with a bend as usual, to allow for contraction and expansion. The number of blows given varies according to the steam pressure, and the opening of the steam cock; it is

With 90 lb. pressure, and cock 1/2 open, 170 blows per min.
" " " " 1/3 " 136 "
105 " " " 1/2 " 240 "
" " " " 1/3 " 156 "
" " " " 1/5 " 136 "
120 " " " 1/3 " 228 "
135 " " " 1/5 " 200 "

To start the bell, the cock is opened full, and afterward partly closed. The blows follow in such rapid succession that a kind of uniform sound with louder intervals is produced, but not of the same shrill character as by a steam whistle. The same kind of bell is used on the shunting engines in goods yards, where roadways have to be crossed on which lurries and handtrucks circulate, and the results as far as prevention of accidents is concerned are stated to be very satisfactory.

* * * * *

LIEUT. GREELY BEFORE THE BRITISH ASSOCIATION.

Lieuts. Greely and Ray were received with distinguished honors at the meeting of the British Association in Montreal. A complimentary luncheon was tendered him by the members of the British Association for the Advancement of Science, at the Windsor Hotel. General Sir Henry Lefroy presided. In response to the toast "Our Distinguished Guests," coupling the names of Lieuts. Greely and Ray and Mrs. Greely, Lieut. Greely said:

"_Mr. President, Ladies and Gentlemen_: I need scarcely say that this flattering reception from representative men of one of England's most distinguished societies touches deeply my feelings as a soldier and as a man. It is not alone that you represent the science and learning of England and the world, but that you are all countrymen of those daring seamen and explorers whose names and whose deeds have become household words throughout the world. Hudson, Baffin, Cook, Nelson, Parry, Franklin, and a score of others among the dead; McClintock, Nares, and Markham, and last, but not least, the man whose name was oftenest on our lips when praying for relief during the past terrible winter--Bedford Pim. What those men have done the whole world knows. That you should deem aught that I have done worthy to placed with the deeds of those illustrious men must always be a source of pride to me. For three centuries England maintained against the world the honors of the farthest north. Step by step every advance was made by Englishmen. Now England's grandest colony presses to the front; but none the less is the honor England's, for at the price of her sons' lives and by their toil the path was cleared. But for Beaumont's dauntless pluck and indomitable energy in 1876, Lockwood would never had made his great northing in 1882. I have during a quarter of a century's service, as becomes a soldier, been jealous of my honor. I have striven to maintain it in the field, fighting and bleeding for my country, and at my desk studying and discussing scientific data; in the Arctic Circle, when pursuing scientific and geographical work, or later, when stranded by adverse fate, and starving and freezing upon the barren coast. This marked and public testimonial of your approval cannot fail to make me doubly jealous of it in days to come."

Lieut. Ray followed, returning thanks in his own behalf.

After other speeches Sir Henry Lefroy presented Lieutenant Greely with the following informal address:

"Montreal, Sept. 2, 1884.

"The undersigned, on behalf of many warm friends and admirers, and
as representing various professional and scientific pursuits,
desire to express to you their appreciation of the courage and
devotion which has characterized your conduct during the trying
circumstances of your late Arctic service. We trust that your
health may soon be restored, and that you may long be spared to
tender, as during your past distinguished career, those valuable
and distinguished services to your great country which have already
placed you among the foremost of scientific explorers of the age.

"Yours faithfully, Rayleigh, President."

In introducing Lieut. Greely, Sir Henry Lefroy, referring to the persistence of purpose shown by his party in bringing back the pendulum apparatus, remarked that there was nothing nobler in the annals of scientific heroism than the determination of these hungry men to drag the cumbersome box along their weary way.

It was fully two minutes after rising before Lieut. Greely could speak, so great was the outburst of enthusiasm which greeted him. He remarked that he was surprised to learn that the ground did not thaw lower at Lieut. Ray's station, which was ten degrees farther south than his own, where the ground thawed to a much greater depth--namely, twenty to thirty feet. In regard to an open polar sea, he differed from Lieut. Ray. He did not believe there was a navigable sea at the pole, but he was of the opinion that there was open water somewhere about.

The geographical work of the Lady Franklin Bay expedition covers nearly three degrees of latitude and over forty degrees of longitude. Starting from latitude 81 deg. 44 min. and longitude 84 deg. 45 min., Lieut. Lockwood reached, May 18, 1882, on the north coast of Greenland, latitude 83 deg. 24 min. and longitude 40 deg. 46 min. From the same starting point he reached to the southwest, in May, 1883, Greely Fiord, an inlet of the Western Polar Ocean, latitude 80 deg. 48 min. and longitude 78 deg. 26 min. This journey to the northward resulted in the addition to our charts of a new coast line of nearly 100 miles beyond the farthest point seen by Lieut. Beaumont, R.N. It also carried Greenland over 400 miles northward, giving that continent a much greater extension in that direction than it had generally been credited with.

In a subsequent speech he took occasion to say that a fact had surprised him. It was the discovery that when the tide was flowing from the North Pole it was found by his observations that the water was warmer than when flowing in the opposite direction. He took the trouble to have prepared an elaborate set of observations showing this wonderful phenomenon, which would eventually be published. To him these pecularities were unexplainable, and be hoped that the observations would be studied by his hearers, and some explanation found in regard to the thermometric observations of the expedition. He remarked that the mean temperature for the year of the hourly observations was 5 degrees below zero, which justified him in saying his station was the coldest point of earth ever reached.

* * * * *

DIAMOND MINING IN BRAZIL.