ly worn away; but experience has shown. that interruptions in the flow seldom cause any deterioration which prevents the continuance of the machine in service after the flow is re-established. The tendency of the bearing in such cases is to wear itself to a new surface so that it operates normally.

It has been found that the vertical turbine can also be operated without loss of efficiency, even when subjected to a high overload. One

reason for this advantage is that it is readily governed by changing the number of nozzle-sections in flow, and therefore can be regulated to the service required. The speed when operating with a variable load, is controlled by the automatic opening and closing of the original admission nozzle-sections, the number of nozzle-sections corresponding to the load always being kept in flow. A centrifugal governor attached to the top of the shaft imparts motion to levers, which in turn work the valve mechanism. There are a number of valves, each communicating with a single

683

nozzle-section, or, in some cases, two or more nozzle-sections. These valves are connected to long pistons, by which the valve can be opened or closed by steam. The motion of each of these pistons is controlled by a small pilot valve, which is worked by the governor mechanism. The movement of the governor mechanism actuates the pilot valves successively, and the main valves are opened or closed by the steam.

For marine service, as well as for the ordinary power station, various forms of

pounds of steam per hour when in service with full load.

Reference has already been made to the area of floor space required for the turbine as compared with other forms of steam motors. The space needed for the former is actually so small in proportion, that it seems almost incredible that from a turbine an amount of horse-power can be obtained which will be equal to that secured, for example, from a reciprocating engine which occupies possibly ten times as much room in the power station.

W

HEN our coal fields are exhausted of their stored carbon, science will convert water into light and heat, and the sun's rays into power; but in the process of harnessing tides, wind, and light rays, we are coming back to the simple methods of the ancients in their effort to make available the surrounding agencies of nature.

It may be said that nearly all permanently useful progress is toward simplicity; but the human mind is so constituted that it likes to wander afield, and reaches results oftentimes by the most indirect route.

The Steam Turbine

For upward of three centuries now, the steam engine has been passing through an evolutionary process which has refined and complicated it to such a degree that only a specialist in thermodynamics can fully comprehend all the multitudinous parts. But, just as the involved reciprocating steam engine has reached a

MEASURING WATER FLOW BY MEANS OF WEIR.

point of development at which it appears doubtful to the minds of inventors that

Illustrations by courtesy of Dayton Globe Iron Works Company, Risdon-Alcott Turbine Company, and S. Morgan Smith Company.

further improvements can be made, the world is startled by the announcement that the steam turbine is the engine of the present and the future, and that the refined and perfected reciprocating engine is foredoomed to final abandonment. The steam turbine becomes the established engine of the future because of its simplicity. It is a return to a primitive type. At first glance, all the elaborate technical literature and experiments built up around the steam engine appear wasted; but all knowledge is valuable, and the human efforts put forth to perfect the compound and reciprocating steam engines cannot be counted as useless. They all have an important bearing on the new models of an old type of power producer.

The modern steam turbine, in principle. at least, is practically a combination of Branca's wheel and Hero's æolipile. Branca invented his steam wheel device in 1629; and Hero of Alexandria, his æolipile about 200 B. C. From these crude inventions, the steam turbine has suddenly developed into the commercial power-producer of to-day. Whether for driving the huge machinery of ocean steamers, or for generating electricity to operate street railways, or to light city streets and homes, the steam turbine seems destined to prove the most popular because the most simple and economical of steam engines.

The Gas Turbine

The problem of perfecting the gas turbine promises further advantages with this simple form of power-producer. If a continuous combustion of gas under pressure can be obtained, we shall come one step nearer to the goal of direct conversion of the energy of fuel into electrical energy. The gas turbine will then possess the great advantage of conduct

ing the stored energy of carbon directly to the prime mover, practically eliminating the boiler and the necessity of a water supply.

The Turbine Water Wheel and the
Windmill

In harnessing the tides and currents of rivers and streams, the turbine wheel follows the same general principle that is being so elaborately sought after in the gas turbine. A return to the water-wheel principle is characteristic of the century. Just when our picturesque water-wheel mills are falling apart through neglect, the turbine wheel of a Niagara or a Messina calls a halt. The windmills have also fallen into decay along our New England streams; but in the new West they are springing up like mushrooms. to irrigate arid regions for agriculture. They pump the water from underground reservoirs, and make the very desert blossom as a garden. The harnessing of them to electrical generators to do work on farms, adds further to their usefulness. The hot, dry winds of the prairie. districts, which have proved a bane to the thousands of farm holders, are suddenly converted into blessings. With windmills for irrigating land, and for supplying farms with electrical power to operate machinery, the new farmer will become independent of weather conditions, and increase his products tenfold. The direct conversion of wind power into electrical energy, it is true, is still in its infancy; but its successful operation even on a small scale promises to inaugurate an era of agricultural changes that as yet can only faintly be measured,

The Solar Motor

On the Pacific coast, where the sun's rays are hot and constant throughout the greater part of the year, and down in the arid regions of New Mexico, where the heat of summer is almost unbearable, the solar motor works with equal promise of great revolutionary developments. By concentrating the rays of the sun upon a focal point-which is the boiler of the new type of motor-metal can be fused within a short time, and water boiled within an hour after sunrise. The energy of the sun's rays, converted directly into steam power, performs the work of man without friction or trouble. With automatic regularity it grinds corn, threshes wheat, or runs a dynamo for electrical transmission. This form of solar motor, in hot climates, insures for those regions a power that is as abundant and widespread as the light of the sun itself. It is as free and as widely distributed as the air we breathe.

Stored Energy of Streams

The distribution of water, fortunately, is almost as general as that of air and sunlight; and its employment for produc

the New England cotton mills established an industry in the oldest section of the country that has not been crowded out of existence by modern applications of steam and electric power.

In its early form, however, the water wheel or turbine has been steadily losing ground. It involves a waste of energy that cannot be overlooked in this age of progress and development. The ideal conversion of the power of a stream into electrical energy for long- or short-distance transmission, utilizes the full value of the current, and transforms one of the most abundant of elements into a working agency for man.

The harnessing of Niagara appeals to the imagination as no similar work on a smaller stream could possibly do; but in the aggregate, the hydraulic power of the thousands of small rivers, streams, and

through flower-decked meadow or swamp. The rippling rivulet that tumbles so gracefully and noisily from rock to rock, and finally loses itself in the turgid bosom of the broader river of the lowlands, is rich in possibilities for the future, containing a potential value that is often overlooked. The muddy ditch that drains the lowlands, and slowly finds its way to some creek or brook, represents a value that may be estimated in any number of horse-power of working energy, when properly harnessed. And even the bubbling spring that furnishes a cool drink to the thirsty, represents a small power plant which may be turned into great usefulness for man's purposes.

The hydraulic possibilities of a brook or stream appear too small and insignificant to most of us; and little thought of developing these sources of energy has

FLUME VALVE FOR REGULATING FLOW OF WATER TO TURBINE.

occurred to man in the past. It is only since practical electrical engineering has reached a stage of development which makes every stream of water teem with potential value, that serious consideration has been given to the small water supplies. Along thousands of unfrequented streams to-day, electrical science could build up industrial centers, or establish local power plants to operate farming machinery, to light houses and streets, and to conyert the wilderness into fruitful fields and gardens. Through hundreds of farms, small watercourses run which possess more potential value than the soil that has for so many decades been laboriously cultivated.

Agricultural Applications

A farm with ten or fifteen head of working horses is considered a goodsized place, according to Eastern standards of agricultural measurement; and it would represent several hundred acres of tillable soil. But a single watercourse with moderate flow and velocity contains a potential energy of great value for doing the farm work. During the seasons of the year when this flow would be increased, the horse-power available would rapidly mount up to nearly double; or, if storage reservoirs were constructed to hold the supply for uniform use the year round, a further increase of available.

power could certainly be depended upon. The average American stream finds its source either in the foothills of mountains, or on some high elevation where a considerable watershed is formed. The drainage of a large tract of land by the stream makes its flow very irregular. In the spring and winter seasons, the stream is swollen to such unusual proportions that it overflows its banks and inundates the surrounding country; or if confined in a narrow bed by high, rocky sides, it forms a violent torrent which is liable to wash away everything that obstructs it. A violent, rushing, turbulent stream six months in the year, it becomes in the summer season a mild, apathetic watercourse that almost stagnates in its bed, drying up finally in places so that only a tiny rivulet flows down its channel. This unreliability of the streams has been a source of anxiety and great expense to manufacturers for decades, and the annual floods and washouts of mill property cause losses of millions of dollars.

The streams that would yield from 500 horse-power down to 50 horse-power are numerous, and are so well distributed that few parts of the country can be said to be minus great possibilities in this direction. With a small stream of 25 cubic feet per second as the minimum flow, and a working head of ten feet, the amount of power that could be developed with