umns were erected. The structure rests on seven piers, each consisting of four hollow iron columns, cross-braced in sections of uniform height, and spreading at the base like the letter A. The track rests on lattice girders, which in turn rest upon the apex of the A. There is, therefore, nothing intrinsically remarkable about the plan of construction. In the absence of trustworthy data it was necessary to take extraordinary precautions against wind force. The calculations were therefore made to resist pressure that would blow a train of empty trucks from the track, the estimated condition of least stability being when a bridge is loaded with an empty train. The calculations, it should be noted, took into account the weight of the atmosphere, which is only about two thirds that at the sea level. No temporary staging was used. A wire-rope tramway stretched from side to side of the canon was used to transport and place the different parts where they were needed-a device successfully employed in many works now in progress in this country. This tramway was also used to carry a locomotive piecemeal across the canon-a service which was successfully performed, but which, when the boiler was sent across, strained the ropes to an alarming degree. The girders were put together on the abutment and transported to their places complete with the aid of the tramway and a crane. The iron columns were tested before shipment from England, and endured a longitudinal pressure of 600 tons without measurable deflection. The labor was all done by men, mostly sailors, unskilled in this kind of work, superintended, of course, by trained engineers. The principal dimensions of the viaduct are: Length between abutments.. Length of principal spans.. 800 ft. 386 ft. 814 ft. 80 ft. 1,115 tons. 1 tons. 24 ft. The structure was designed by Edward Woods, C. E., and Joseph Harding, C. E., and the construction was superintended by Peter Fisher and Joseph Fisher, who came out from England for the purpose. The viaduct, exclusive of the masonry foundations, was put together in a few days more than nine months, and without loss of life or serious accident. Canalization of Rivers.-Outside of professional circles it is not generally known that a great deal of attention is now given in Europe to the improvement of internal navigation. În the "Annual Cyclopædia" for 1888, the hydraulic canal-lift at Les Fontinettes, France, was described and illustrated. Since then other similar structures have been completed or begun at several important points in Great Britain and on the Continent. Not only is interest largely centered on artificial water-ways, but the conversion of shallow rivers into navigable streams is attracting attention. In 1884 a meeting of Belgian, Dutch, and German engineers convened at Bremen, to consider possible improvements within their respective boundaries. From this resulted the first international congress at Brussels, in May, 1885. A second congress met at Vienna, in June, 1886, and the third took place in August, 1888, at Frankfort-on-the-Main. It The is authoritatively said that there is quite a general revival of canal construction in connection with the canalization of rivers. Early in the present century enterprises of this character were pushed forward with much energy, but the construction of railroads temporarily checked work, and the nations are now learning the lesson that after all speed is not everything in questions of transportation. In America, while the conditions are somewhat different, we are undoubtedly nearing a period when internal water transportation will resume at least a share of its former importance. In the international congress at Vienna it was decided that under some circumstances navigable ways could be profitably operated in competition with railways. boats carry raw material at rates that are not remunerative to railroads, and thus deliver material at the manufacturing centers which otherwise would not reach them at all. This largely increases the manufactured product, which in turn reacts favorably to the railroads by increasing their paying traffic. According to M. Boulé, probably the highest European authority on the subject, the Rhine, the Elbe, the Seine, and the network of canals extending from Belgium to Paris in the north of France are to-day successful competitors with parallel and prosperous lines of railroad. Experience," he says, "has shown that the most prosperous railways are those that run by the side of the most frequented water-ways. Wherever the latter have been improved not only has a boat-service subsisted, but its traffic has increased without hindering the development of the railway." In the United States the question of the improvement of water-ways has been discredited by the abuses connected with appropriations under successive river and harbor bills, but nevertheless much has been accomplished. Adjustable dams have been constructed on many Western rivers through combined private and public enterprise, but our engineers may gain many suggestions from the experience of their European brethren. Very many devices have been successfully employed to deepen channels temporarily by means of adjustable dams, rolling shutters, and the like. Some of the latest inventions in this direction are embraced in the large works on the Seine, below Paris, and some of them are illustrated in the article on "Irrigation." Country Roads.-In a comparatively newly settled country the making of good roads is necessarily slow, but there are encouraging indications that people are at last waking up to the enormous waste of material due to the careless methods heretofore followed by local road commissioners. In several States the authorities are taking steps to have repairs and construction carried out under competent supervision instead of leaving them wholly to unskilled labor. This movement is largely due to the action of the various bicycle clubs throughout the country. Actuated, at first, no doubt mainly by selfish motives, these associations, being composed largely of young men of means and good social standing, have been able, in a perfectly legitimate way, to bring political pressure to bear upon the authorities with highly commendable success. Probably the most extensive system of excellent roads in this country is in the vicinity of Boston, where, in a radius of twenty miles, more or less, almost all the roads are in good passable condition at all seasons of the year, save only when buried under deep snow. In New Jersey the movement in favor of road improvement has assumed sufficient magnitude to be ranked among the important engineering undertakings of the day. The specifications are carefully drawn and provide for road-beds sixteen feet wide graded to a depth of eight, ten, or twelve inches according to anticipated weight of traffic. All unfit material is removed and replaced with gravel, slag, provided for by a central opening in the top of the shoe, through which water is forced at a pressure of 150 pounds to the square inch. Each carriage rests upon several of these shoes. Let us suppose the train to be at a stand, all the shoes resting squarely upon the rails. A valve is opened and water is forced through supplypipes down through the opening of each shoe. It spreads under the shoe, and contact with the rail ceases-the train is literally afloat. The water speedily leaks out around the edges of the shoes, but the supply is kept up from a reservoir mounted on the train, and under the requisite pressure from compressed air. The motive power that drives the train is also hydraulic. Under each car is what may not inaptly be described as a rectilinear turbine- that is, a trough fitted with cross or cinders. It is then well rolled with a five-ton roller. Foundation stones of trap rock are laid breaking joints, with the interstices filled with chips and spalls, and over this macadam in two courses rolled and filled in the most approved manner. Such roads are expensive as compared with the average country road, which is nearly impassable after a heavy rain, but they will very soon save their cost in wear and tear of vehicles and horse-flesh. Hydraulic Railway.--Nothing at the Paris Exhibition attracted more universal attention than the "Chemin de Fer Glissant" of M. Barré. The little railway was five hundred feet long, supported by a light iron trestle about six feet high. The rails were of cast iron, nine inches wide, and rested on longitudinal timbers. The principle of the road is so simple that it can be easily understood. The invention originated with the late M. Gerard, inventor of a turbine wheel, but it has been brought to its present stage of development by M. Barré. It will be readily understood that if a large number of small spheres-fine shot, for instance-are placed between two flat metal plates, the plates will move easily one upon the other, even under considerable pressure. The principle is identical with that of anti-friction axle-bearings. If the plates are separated by a thin layer of water, the conditions for free movement are still more favorable, since water is composed of an infinite number of small globules with very little friction among themselves. The nine-inch rail, then, is one of the plates, and a flat patin or shoe, about eighteen inches long and nine inches wide is the other. With a thin layer of water between them it is evident that the one will move readily upon the other so long as the layer of water remains to separate the metal surfaces. This is SECTION OF TRAIN. blades. Along the track is a water main with stand-pipes at regular intervals, corresponding nearly with the total length of the train. When it is desired to set the train in motion, a valve is opened, through which a stream of water is projected into the buckets of the straightened-out turbine under the cars; so slight is the friction of the floating train that it at once moves off easily and smoothly. The stand-pipe continues to discharge water while the train is passing the first opening, upon which it closes automatically, and the work is taken up by the next stand-pipe. The working of the road excited the admiration of railroad experts from all over the world, and it appears to have done all, and more than all, that its inventor claimed for it. While it can only be introduced where there is an adequate watersupply, there are, it is believed, many places where its advantages are obvious. The absence of noise, dust, and cinders, for instance, would render it very desirable on such lines as the elevated railways in New York. The consumption of water is far less than would at first thought seem unavoidable. The outflow from the shoes, as well as from the propelling apparatus, falls at once into suitable water-ways, and is used over and over again. The amount of water used in operating the experimental section in Paris is given by M. Barré as follows: 13 gallons a minute for each patin or shoe, and 8 gallons per ton, for a mile, under a pressure of 150 pounds. There is scarcely any resistance at all on a level, save from the air, which accounts for the moderate expenditure of water for propelling. The experimental section of 500 feet was passed over in 30 seconds, including starting and stopping-a rate of about eleven miles an hour, which is certainly very creditable for so short a line. Eliminating non-essential details, the upper illustration shows A the car-body, B B the shoes or slides supposed to be separated from the track CC by a thin film of water. D is the water main discharging water through its nozzle E against the curved plates F F F F. The train moves as the arrow flies. The lower right hand illustration shows a portion of a car and attachments as they actually appeared in Paris. It is said that Sir Edward Watkin, of the Metropolitan Railway of London, was so impressed with the excellence of the hydraulic system that he has authorized the construction of an experimental section near the city. Electric Mountain Railway.-An interesting example of transmission of power by electricity is found in the railway up the Burgenstock near Lake Lucerne, Switzerland, which was opened to the public early in the summer. The power is generated by two dynamos driven by a water wheel, nominally of 125 horse-power, at the mouth of the river Aar, three miles distant. The power is transmitted through insulated copper wires with an estimated loss of about 25 per cent. The dynamos are each nominally 25 horse-power. A single pair of rails is used, the line being altogether 938 metres long, curving along the almost perpendicular side of the Burgenstock to a height of 1,330 feet above the lake. The gradient is 32 per cent. at the foot of the line, but is increased to 58 per cent. after the first 400 yards, and this is maintained to the summit. The action is said to be as steady and smooth as on an ordinary line. Cable Traction for Boats.-An interesting series of experiments has been instituted at the Junction of the St. Maur and St. Maurice canals, France, with a view to substitute traction cables supported on poles for the usual methods of propulsion, namely, tow boats, men, or animals. The matter was intrusted to M. Maurice Levy, an engi doubled, so that by casting off one end the connection with the moving cable is severed at any moment. The section of cable shown here represents it at an extraordinary height above the tow-path. At the regulation level it is within easy reach of the ground, and as the rate of speed is only about 2 miles an hour it is easy for a man to attach or detach the tow-line as required. Upon a straight stretch of canal a faster rate could no doubt be safely maintained. The notches shown in the periphery of the pulley are designed to facilitate the passage of the links. Wave-Motors. In the "Annual Cyclopædia" for 1886 was illustrated a rude pump actuated by wave motion, which was in actual use near Alexandria Bay. The idea has since been utilized on a larger scale along the sea-coast, where the regular and well-nigh ceaseless swell of the ocean furnishes an enormous amount of power that has heretofore gone to waste. The illustration represents one of a series of pumps established at Long Branch, where they were employed in pumping sea-water into tanks for use in various ways about the town and the hotels. A similar pump of far greater size and power was constructed near San Francisco, on the Pacific Coast, but was destroyed by a vessel that drove ashore during a gale. The device is so simple and the machinery so inexpensive that it would seem available for the translation of wave power in many places when no other natural source of energy is to be found. ERICSSON, JOHN, engineer, born in Langbanshyttan, province of Wermland, Sweden, July 31, 1803; died in New York city, March 8, 1889. His father, Olaf, was a mine owner, and his mother, Sophie, was the daughter of an ironmaster. Unfortunate investments in mining property had made the family poor at the time of John's birth. Of his childhood it has been said that he was impatient of routine, and of his peculiarities it has been written that "when scarcely out of leading-strings he made himself the victim of family discipline by stubbornly insisting upon going around on all fours, in a manner peculiar to himself and which nursery tradition could not tolerate." When he came to learn the alphabet he at once understood that the various letters shown him were but symbols, and was soon found at work with a sharp stick, drawing in the sand of the lake beach signs which he proposed to adopt as a substitute for the Swedish alphabet. He received his earliest instruction from a Swedish governess, and then was taught by a German engineering officer. He developed extraordinary mechanical and mathematical genius, and before he was eleven years old produced a saw mill of ingenious construction, the frame of which was of wood, the sawblade made from a watch-spring, and the crank cast from a broken tin spoon. He also planned a pumping engine to clear the mines of water. This work attracted the attention of Count Platen, then in charge of the Götha ship-canal, on which Ericsson's father was employed, and through his influence the boy, when he was twelve years old, was appointed a cadet in the Swedish corps of mechanical engineers. After six months' study, he was made a leveler on the ship-canal, and at the age of fourteen he was assigned to set out the work of a section, employing 600 soldier operatives. It was necessary for an attendant to follow him with a stool, on which he raised himself to the height of the leveling instruments. He occupied his leisure in preparing a set of drawings, showing the most important parts of the ship-canal as well as all of the machinery and implements used in its construction. He entered the Swedish army as ensign in 1820, and was soon promoted to a lieutenancy, when he was assigned to the Royal Field Chasseurs of Jämtland. Shortly afterward he passed with distinction a competitive examination for an appointment on the survey of northern Sweden. His work in this capacity exceeded that of his fellows, and, as the surveying was paid for by the piece, he did double work. In order to avoid criticism, he was carried on the pay-rolls as two men. Meanwhile he undertook the preparing and engraving of a series of plates illustrating the Götha Canal. For this purpose he designed a line-engraving machine, by means of which, within a single year, he completed eighteen copper plates, each of 300 superficial inches. The utilization of flame as a means of developing mechanical power next engaged him, and he built a condensing-flame engine of ten horse-power. His drawings were shown to the king, Charles John, who, recognizing his wonderful ability, advised him to go abroad, since his own country could not reward him as he deserved. In 1826 he obtained leave of absence, to visit England and introduce the engine there; but he never returned to Sweden, and in the following year resigned his commission in the army, having meanwhile attained the rank of captain. The engine was not successful, as the flame produced by mineral fuel was far less in volume than that derived from a pine-wood fire, and the intense heat from the coal soon destroyed the working parts of the machine. New experiments were instituted, which resulted in the completion of an engine that Ericsson patented and sold to John Braithwaite. He then produced in rapid succession an instrument for taking sea soundings, a hydrostatic weighing machine, an apparatus for making salt from brine, a file-cutting machine, and many other devices, including tubular steam boilers and artificial draught by centrifugal fan-blowers, dispensing with huge smoke-stacks, economizing fuel, and showing the fallacy of the assertion that the production of steam was dependent on the amount of fire-surface. In the steamship "Victory" he made, in 1828, the first application to navigation of the principle of condensing steam and returning the water to the boiler, and in the same year submitted to the Admiralty his self-acting gun-lock, the peculiarity of which was that, by its means, naval cannon could be automatically discharged at any elevation, notwithstanding the rolling of the ship. He was unable to agree as to the terms of its adoption in the British navy, and then kept the secret of this invention until 1843, when he applied it to the wrought-iron guns of the "Princeton." In 1829 the Liverpool and Manchester Railway offered a prize of £500 for the best locomotive capable of fulfilling certain stipulations. Five loco motives entered the contest, and the "Novelty," planned and completed in seven weeks by John Ericsson, was placed on the trial ground. It exceeded its competitors in lightness, elegance, and speed, attaining the then amazing rapidity of thirty miles an hour; but the "Rocket," designed by George Stephenson, proved superior in traction, and was awarded the prize. In the "Novelty," Ericsson demonstrated the fallacy of the theory that a certain extent of surface was necessary for the generation of a given quantity of steam. He also introduced into its construction several new features, the four most important of which are retained in the locomotive of the present day. Nearly half a century later John Bourne wrote: "In locomotive engineering, nothing more original or more elegant has been produced than the Novelty.'" During the same year, Ericsson invented a steam fire-engine, and on the burning of the Argyle Rooms in London in 1829, "for the first time fire was extinguished by the mechanical power of fire." A larger engine, built for the King of Prussia, soon afterward saved valuable buildings at a fire in Berlin, and a third was built for the Liverpool docks in 1830. The Mechanics' Institute of New York city gave him in 1840 its great gold medal for the best plan of a steam fireengine. In 1830 he introduced "link motion' for reversing locomotive engines, and a modification of this device is now in use on all loco motives. His famous caloric engine was given to the world in 1833. In this he endeavored to show that heat is an agent that undergoes no change, and that only a small portion of it disappears in exerting the mechanical force developed by steam engines. A working model of five horse-power was built, in which he placed the "regenerator." Lectures were delivered on it by Dr. Dionysius Lardner and Michael Faraday, and it was highly approved by Dr. Andrew Ure and Sir Richard Phillips. At first it proved unsuccessful, owing to the necessarily high temperature, which produced oxidation and destroyed the valves and other working parts. In 1853 the caloric ship “Ericsson," of 2,000 tons, was propelled by a motor on the same principle. A trial trip from New York to Washington and back showed great economy in fuel, but at a speed too slow to compete with steam. For several years thereafter Ericsson devoted himself to the improvement of the stationary caloric engine, and nearly 10,000 such engines have been built, hundreds being employed in New York city for pumping water in private dwellings. In 1862 the American Academy of Arts and Sciences awarded the gold and silver Rumford medals to Ericsson "for his improvements in the management of heat, particularly as shown in his caloric engine in 1858." This was the second bestowal of this award, the first having been made to Robert Hare, in 1839, for his oxyhydrogen blow-pipe. In 1836 Ericsson invented and patented the screw-propeller that revolutionized navigation, and in 1837 he built a steam tug, the "Francis B. Ogden," with twin screw propellers, which on trial towed the American packet ship "Toronto" at the rate of five miles an hour on the river Thames. Subsequently the Admiralty barge was towed ten miles an hour; but, despite the practical demonstration, these dignitaries decided that "even if the propeller had the power of propelling a vessel, it would be altogether useless in practice, because the power being applied to the stern, it would be absolutely impossible to make the vessel steer." Francis B. Ogden, a pioneer in steam navigation on American waters, at that time United States consul in Liverpool, appreciated the value of the invention, and in 1838 he was interested with Ericsson in the construction of the iron-screw steamer "Robert F. Stockton," which crossed the Atlantic under canvas in 1839 and was afterward employed as a tug-boat on Delaware river for a quarter of a century. Through Mr. Ogden, Ericsson was presented to Com. Robert F. Stockton, who urged his coming to this country, In 1839 he resigned his place in London as superintending engineer of the Eastern Counties Railway, and came to the United States in November. Com. Stockton exerted his influence with the authorities in Washington for permission to build a steamer from Ericsson's design, and under his own superintendence. A change of administration intervened, and it was not until 1841 that permission was given him to furnish designs for the screw war-ship “Princeton,” the first vessel ever built with the propelling machinery below the water line out of the reach of hostile shot. Besides its screw propeller, the "Princeton" was remarkable for numerous me |