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length of the cylinder in a spiral course. As the steam expands the size of the wheels is increased to correspond with the high pressure, intermediate and low pressure cylinders of a reciprocating engine, and the buckets are enlarged proportionately.

A Westinghouse-Parsons steam turbine, which is the Americanized type of the Parson turbine, of 500-horsepower, has 58 rings of buckets. Each bucket contributes about one ounce toward the total of 500 horsepower. From this it may be seen that it requires an enormous number of pieces to make up a steam turbine of this type. The 18,000 horsepower steam turbines to be installed in the new Cunarders will each have 1,250,000 buck

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type of steam turbine yet produced waspatented some six years ago by C. C. Curtis, of New York City, and developed by the inventor in collaboration with W. L. R. Emmet, of Schenectady. The Curtis steam turbine differs radically from others, in many particulars. The turbine wheels or disks are much larger in diameter and fewer in number than in the Parsons type and they revolve horizontally instead of vertically. This arrangement affords an opportunity for a most ingenious method of reducing friction almost to the vanishing point. The turbine shaft which bears the full weight of the heavy steel wheels and also the moving parts of the dynamo does not rest on a bearing at the bottom, but, instead, is actually floated on a layer of water half an inch deep, which is pumped into the chamber at the rate of 300 gallons a minute, at a pressure of 400 pounds to the inch. One of these Curtis steam turbines of 7,000 horsepower has three solid steel wheels, 14 feet 7 inches in diameter and from 11⁄2 inches thick at their circumference to six inches at their center, revolving in a chamber 5 feet 6 inches high. So nearly is friction eliminated and so perfectly are the wheels balanced that if all the load be taken off, one of these great turbines will continue to revolve for two hours after the steam is turned off. By a steady pull to overcome inertia the huge mass can be turned with a man's little finger.

The large size of the wheels in the Curtis turbine is one of the means of reducing speed to practical limits. Each wheel revolves in a separate chamber. Each has two rows of buckets on its periphery which bestride a stationary ring of buckets on the inner wall of the chamber. The steam, on being admitted through the nozzles in the wall of the chamber, acts on the first row of buckets, passes from this to the stationary ring, is deflected against the sec

ond row on the wheel, and then passes out of the chamber, through nozzles similar to the first set, though larger, to the next chamber, and so on to the condenser.

Now that the development of the steam turbine has been accomplished in these two notable types, the first really great improvement in the steam engine since the days of Watt has been achieved. Not only are the turbines now in use doing their work 30 per cent cheaper than it can be done by the best types of reciprocating engines, but there is also a great saving in the original cost. It has been shown that in a big plant each turbine of 7,000 horsepower can be set up for approximately $80,000 less than the cost of reciprocal engines of equal power. The saving of space, particularly by the Curtis vertical turbine, is very great. A Curtis steam turbine of 5,000 horsepower requires but 35-1,000th of a square foot of floor area per horsepower as compared with 7-10ths of a square foot per horsepower required by a vertical reciprocating engine.

True, the steam turbine has its limitations. From its very nature it never can be adapted to the locomotive. The efficiency of the steam turbine lies in its high speed. Locomotives may be required to attain high speed, but first they

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INTERIOR OF SHELL OF A CURTIS STEAM TURBINE.

must start a heavy load by a slow pull upon which their maximum power must be exerted. But the very thing that disqualifies the steam turbine for the locomotive makes it peculiarly serviceable for the development of electric energy. For generating an electric current, high speed is required. Heretofore, it has been necessary to drive dynamos with belts in

speed of the turbine and how to change the pitch of the propeller blades to adapt it to a swifter gait, and now steam-turbine-driven ships are making wonderful records.

The British Government built four cruisers exactly alike, equipping two with the usual type of marine engines and two with steam turbines, and set them to

ROTARS ON SHAFT READY TO GO INTO 120-INCH TURBINE.

steaming about to see what they could do. It was found that the turbine ships could make 1.9 knots an hour greater speed on 10 per cent less coal than the vessel with the old-style engines. In addition to their economy the turbine caused so little vibration that the vessels plowed through the water as quietly as a sailing ship.

Altogether the marine steam turbine has made so good a showing that the ultra conservative Cunard Company has let contracts for building two steamships, 800 feet long, larger than any yet constructed, to be equipped with steam turbines. These ships are speed of 26 knots an hour, or two and a half knots faster than the swiftest vessels now in service. The Carmania, the first Cunarder to be equipped with turbines, has been able to develop a knot more speed than her sister ship, the Caronia, which has quadruple expansion engines, with 5 per cent less weight of machinery and 15 pounds less steam pressure. The vibration, as recorded by instruments, is exceedingly slight.

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order to get the speed; or, if the dynamos to have a
were on the same shaft with the engine-
"direct connected," it is called-it has
been necessary to have the revolving field.
very large in order to get the peripheral
velocity needed. The problem with the
steam turbine has been to reduce the
speed sufficiently to use it in driving a
dynamo. The high speed of the steam
turbine makes it practicable to have the
electric generator very compact and
placed directly upon the shaft of the
engine. As electricity is adapted to
nearly everything nowadays, the useful-
ness of the steam turbine is pretty wide.

In the marine field, in particular, the steam turbine has a great future. It took lots of hard thinking to utilize the steam turbine for driving a propeller, for at first the thing went so fast that the water thrown out by the propeller blades did not have a chance to flow back again, and the wheel was left spinning impotently around in a hole in the water. Patient experiments showed how to reduce the

King Edward has been so impressed. with the performance of the steam turbine that he is having a yacht built which is to be provided with that kind of engine.

Even the United States Government, notwithstanding Admiral Melville's adverse report two years ago, has decided to build two turbine ships.

So successful has the steam turbine been on shipboard that already marine turbines of an aggregate capacity of 150,000 horsepower are in use, and one of the

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Wiring the Wilderness

A

By Sampson S. Burton

TWISTING, snaky path has been cut through the heart of Africa. For five thousand six hundred miles a telegraph wire is being stretched through swamp and jungle. When five hundred miles more are strung, Egypt may talk with South Africa, and the Englishmen in Cape Town can reserve their camels at Cairo in advance for their trip to the

NATIVE LABORERS STRETCHING THE WIRE.

Pyramids. Upon its completion, the voice of Cecil Rhodes will echo in triumph across the continent of his adoption, for it is due to his foresight and perseverance that the project is now almost completed. Cecil Rhodes, looking at a map. of the dark continent, placed his finger upon Ujiji, the place where Stanley found Livingstone, and through that point drew the line which would first point toward the civilization of all Af

rica. And now, as was at first planned, one of the chief stations along the line of the new overland and overhead telegraph is the meeting place of Stanley and Livingstone, thus emphasizing the wonderful progress which man has made in the dark continent since 1871.

Cecil Rhodes declared before a meeting of the British South Africa Company in the fall of 1892 that it was his ambition to link Cape Town and Cairo with an overland telegraph. The line would have both a commercial and political significance. England could be brought within quick and direct communication with her African possessions, and an impetus would be given to the growing commerce and trade of Africa by providing a cheap means of communication. Messages could be sent for about twenty-five cents per word, which is less than the cable rate.

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