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heavy motor-car of fifty or seventy-five horsepower and weighing about 4,000 pounds, or a little more than 1,000 pounds in excess of a medium - sized touring car, and little heavier than some of the biggest pleasure machines. Either steam or gasoline serves as a motive power. With gasoline, a fourcylinder motor suffices,
DOUBLE-ACTING STEAM LOCOMOTOR. and with steam a couple of cylinders is deemed sufficient. Beside the motor is carried pulls as does a railroad locomotive its a friction clutch in the engine fly- train of cars. In starting, the wheels of wheel, and in rear of it is a transmis- the traction engine generally slip, tearing sion gear for giving the different speeds up the road surface; and in order that the of travel. From this transmission engine shall be able to pull a reasonable or change-speed gear, extends a pro- load, it has to be excessively heavy to sepeller-shaft over the back axle and cure traction for its wheels. Besides out in rear of the locomotor, where it car- these disadvantages with the tractor sysries a universal joint for coupling with tem, is the trouble experienced in turning the continuous drive-shaft which extends corners, the tractor making a curve of throughout the length of the train. very large radius, while the cars “cut the
The field of usefulness of the Renard corners," turning on curves of lesser train is unlimited, and its advantages radius. over single cars far outweigh its disad- In France the Renard train has been vantages. The locomotor weighs a cou- used in military service with marked reple of tons; the vans when empty weigh sults. A convoy so transported occupies practically the same, and each is capable one-eighth the space of one drawn by of carrying a three-ton load. In a train mules or horses, and it travels at a speed of four cars, the combined weight with of ten miles per hour. Not requiring loads is twenty-two tons, twelve tons of metal tracks, the train can travel over any which are load. This great weight is roads over which horse-wagons can pass, carried on twenty-eight road wheels, a and can mount hills with facility. In load of less than a ton on each wheel. Persia its field is in localities where railShould this weight, twenty-two tons, be roads are not known, and where the excarried on a four-wheel truck of enor- pense of making a road and laying tracks mous size, it would mean five and one would prove poor investment. Holland half tons on each wheel. This great has had several trains in operation for a weight would destroy the road surface couple of years, in combined passenger and would be too heavy for most of the and express service. Other countries in bridges; moreover, it would be impossible which they are in constant use, are to make wheels strong enough or tires France, Germany, South Africa, Australia, heavy enough to withstand the load. The Egypt, India, Russia, Turkey, and Austria. road laws of all countries forbid the car In France recently a train did service in rying of more than a certain load on each transporting newspaper men to the Grand vehicle wheel, a fact which restricts the Prix motor-car race, covering the road sizes of loads carried.
from Paris to the course, seventy miles, In many European countries, recourse at forty miles an hour. For freight uses, has of late been had to the “tractor" the speeds run from a maximum of ten method of transporting heavy loads. In miles per hour to intermediate speeds of this system a traction engine has yoked six and sever miles and a minimum of behind it three or four wagons, which it two miles per lour. When traveling with
full load, the consumption of gasoline approaches three and one-half gallons per hour. Perhaps the most applicable field for the train is in thickly populated countries and manufacturing districts, like the north of France and the central portions of England, where the trains form an inter-city transport system. They call at
the shipping room of the maker, and deliver his goods to the receiving room of the jobber, one handling being sufficient; whereas, with the railroad train, a horse team is needed to take the goods to the depot, while another team is required in order to deliver them to the jobber at their destination.
Friends Old and New
TAKE new friends, but keep the old;
New-made friendships, like new wine,
Age will mellow and refine;
HERE has recently been patented in the chief military, naval, and commercial countries of the world
an invention which is likely us to modify in many different ways the construction of breakwaters, wharves, jetties, etc. It will also introduce an entirely new system of providing stable floating foundations in wave-disturbed waters, for defensive forts, coaling stations, lighthouses, and similar marine structures.
The scientific principle that forms the basis of the patents is an extremely simple one; but the practical working-out of the engineering details has required several years of patient investigation and experiment on the part of the inventor, William E. Murray, a resident of Los Angeles, California.
It will come as a new thought to many people—although a moment's reflection
will make its truth obvious—that when the ocean surface is broken with waves, and even when it is lashed by the wind into heaving and tumultuous billows, the disturbance is only a surface one. In point of fact, the wave-disturbance extends to a depth seldom exceeding fifteen feet. Below this level there is absolute stability; and where there are no currents, the ponderous mass of water, growing denser and denser with increasing depth, rests on the ocean bed firm and immovable.
It was by taking advantage of these static conditions at a depth beneath the surface of the sea, that the Murray system of stable flotation was devised. Ships float almost entirely in the wavedisturbed stratum of the waters, only the lower part of the hull of those of considerable draught being in the steady waters deeper down. Consequently their equilibrium is not maintained; there is
no effective resistance to the thrusts and deep-sea floating lighthouse—then it blows of the billows, and vessels accord- makes possible what hitherto has been ingly pitch and roll under the influence deemed impossible. The fortress may of the heaving waves. A ship built ac- have its gun platform, rising out of the cording to the rules of scientific ship- tossing waters, so steady that a tumbler building cannot turn turtle ; however far full of water will not spill; and the lightshe may heel to one side or the other, house, with its guiding beacon two hunshe will always right herself. But no dred feet above the wave-disturbed surmethod of ship-construction has yet been face of the ocean, will stand straight and devised that makes the vessel steady in firm, just as steady as if it were built on tumbling waters. The biggest, heaviest, solid rock foundations.
How are these apparently abnormal results obtained ? Simply by immersing the floating structures in the fardown stable waters to such a depth, in such a way that the action of the heaving surface waters cannot cause oscilla
tion. On a floating body built STEADY-FLOATING BREAKWATER.
according to this plan, the
thump of a big billow such as and deepest-draught liner afloat has most would make a great ocean liner careen, of her immersed bulk in the disturbed has no unsteadying effect. surface water, and is therefore, although To begin with the simplest form of in somewhat less degree than smaller these steady-floating structures, let us craft, still sensitive to wave action. The take a hollow upright cylinder of iron, same with men-of-war. The steady flo- having attached to its lower end a broad tation of battleships, although long rec- projecting flange, weighted with pigognized as a desideratum of first im- iron, stones, or other heavy material. portance, has been found impossible of Such a body will float vertically in the attainment, so that the aim of their guns, water with the projecting flange for a except when the sea is quite calm, can base. The latter, if the length of the cylnever be from a stable platform, and in inder be sufficient, will be immersed at really tempestuous weather must always such a depth in the dense, stable waters be more or less unreliable.
as to be virtually embedded in a resistThe Murray invention has nothing to ing medium. Anyone having a knowldo with ordinary sea-going craft, which edge of the scientific principle of the are built primarily for speed and for lever, will at once understand that the cargo-carrying; but where these factors action of the waves on the superstructure do not count—where, for example, a is negatived by the resistance of the steady-floating fortress is required, or a deeply submerged portion of the floating
body—that any blow above is counteracted by the strong leverage below, checking any tendency to oscillation.
The greater the depth of submersion, the greater the resistance; for, with increased depth, there is increased density of the water, so that the substructure suspended in this medium becomes more and more immobile. But the broad and sufficiently deep projecting flange plays the all-important part of rendering submersion to any inconvenient depth unnecessary, thus making the device of practical utility in comparatively shallow waters. The flange and the lower portion of the cylinder together displace a sufficient volume of the steady water beneath the region of wave disturbance to main
STEADY-FLOATING FORt. tain the whole body in stable equilibrium, unaffected by the motion of the waves and immobile foundation- a "floating playing around the upper part of the foundation," it may be termed, for the cylinder. It is this combination of the words, under these conditions, cease to be wide-projecting flange with the compar- contradictory. With water ballast used atively short cylindrical tube, which af- as part of the weighting material, the fords the key to the solution of the en- platform may be sunk close to the surtire problem of steady flotation for ma- face of the sea; or, by pumping out some rine structures of a great variety of forms of the water, it may be raised to any and for a wide diversity of uses.
required elevation. This, then, forn Let us illustrate the application of the patented Murray steady-floating fortress principle to a floating fortress. Deep with annular revolving deck; and an exdown below the wave-disturbed waters amination of its special features will show is the hollow, projecting flange properly that a remarkable new machine for both weighted, which affords for the gun plat- defensive and offensive purposes has form above the surface of the sea a wide been evolved.
It is conceded that shore batteries are now inefficient for the defense of cities and harbors against attack by modern battleships; but the Murray floating fortresses can be placed far enough off shore-say, three or four miles—to form a perfect screen of defense that no fleet can approach with impunity. These forts will expose only a small target surface above water; and this will not only be proof against the most modern guns, but the sloping face will cause any striking shells to glance off with comparative harmlessness. Within will be mounted the biggest guns, and the annular revolving platform will give these every direction and great rapidity of fire.
For naval and military purposes, the principle of steady-floating structures can be developed in many other ways. For example, torpedo stations can be
placed still further out to sea than the STEADY-FLOATING LIGHTHOUSE.
floating fortresses, forming an additional