The Progress of Invention in the Nineteenth Century Part 6

No. 10,480, Jan. 31, 1854). In 1835 Davenport constructed a small circular railway at Springfield, Ma.s.s.

[Ill.u.s.tration: FIG. 29.--JACOBI'S ROTARY ELECTRIC MOTOR.]

In 1839 Prof. Jacobi, with the aid of Emperor Nicholas, applied his electric motor to a boat 28 feet long, carrying fourteen pa.s.sengers, and propelled the same at a speed of three miles an hour. About the same time Robert Davidson, a Scotchman, experimented with an electric railway car sixteen feet long, weighing six tons, and attaining a speed of four miles an hour. In 1840 Davenport, by means of his electric motor, printed a news sheet called the _Electro Magnet and Mechanics'

Intelligencer_. In 1851 an electric locomotive made by Dr. Page in accordance with his subsequent patent of 1854, drew a train of cars from Was.h.i.+ngton to Bladensburg at a rate of nineteen miles an hour.

[Ill.u.s.tration: FIG. 30.--DAVENPORT MOTOR.]

[Ill.u.s.tration: FIG. 31.--NEFF MOTOR.]

[Ill.u.s.tration: FIG. 32.--WESTINGHOUSE ELECTRIC MOTOR.]

All these motors were operated by voltaic batteries, and on account of the cost of the latter but little practical use of the electric motor was made until the dynamo was invented. In 1873 an accidental discovery led to the rapid practical development of the electric motor.

It is said that at the industrial exhibition at Vienna in that year, a number of Gramme dynamos were being placed in position, and a workman in making the electrical connections for one of these machines, inadvertently connected it to another dynamo in active operation, and was surprised to find that the dynamo he was connecting began to revolve in the opposite direction. This was the clue that led to the important recognition of the structural ident.i.ty of the dynamo and the modern type of electric motor. The dynamo and the electric motor then grew into development together, and the same inventors who brought the dynamo to its present high efficiency, produced electric motors of corresponding principles and value. In the ill.u.s.tration, Fig. 32, is shown a modern electric motor. It is a Westinghouse two-phase machine, of 300 horse power, of the self starting induction type, designed to operate at a speed of 500 revolutions per minute when supplied with two-phase currents of 3,000 alternations per minute and 2,000 volts pressure.

[Ill.u.s.tration: FIG. 33.--SIEMENS' FIRST ELECTRIC RAILWAY.]

The most important application of the electric motor is for street car operation. The first electric railway was that of Dr. Werner Siemens, at Berlin, in 1879, an ill.u.s.tration of which is given in Fig. 33. The first electric railway in America was installed at Baltimore in 1885, and ran to Hampden, a distance of two miles.

[Ill.u.s.tration: FIG. 34.--OVERHEAD TROLLEY CAR.]

[Ill.u.s.tration: FIG. 35.--UNDERGROUND ELECTRIC TROLLEY SYSTEM.]

The familiar overhead trolley cars, and the far superior conduit trolley system, represent perhaps the largest use made of electric motors. The motors are arranged under the cars in varying forms adapted to the structure of the car. In the overhead trolley, shown in Fig. 34, the current is taken from the overhead wire by a flexible trolley pole, and in the conduit system a trolley known as a plow extends from the bottom of the car through a narrow slot in the top of the conduit and makes a traveling contact with the conductor rails within the conduit, which carry the electric current. Fig. 35 is an end view of a street car of the latter type, with the conduit and conductor rails in cross section.

The current goes from one rail to one bearing surface of the plow, thence to the motor on the car and back to the other bearing surface of the plow and the other conductor rail in the conduit.

[Ill.u.s.tration: FIG. 36.--THIRD RAIL SYSTEM ON THE N. Y., N. H. & H.

RAILROAD--FRONT END OF MOTOR CAR.]

A third system, which has supplanted to some extent the use of steam on short line railways, is the so-called third rail system, of which an example is seen in Fig. 36. A third conductor rail is placed between the usual track rails, and from this conductor the current is taken by a sliding shoe on the car, and carried to the motor and thence through the car wheels to the track rails. To reduce danger from the live rail, the third rail in some systems is made in sections, and, by an automatic switching process as the car moves along, only the sections of the rail beneath the car are brought into circuit, all other portions being cut out.

The use of electric motors has greatly extended, cheapened, and expedited the street car service. All the princ.i.p.al thoroughfares of cities and even towns are now so equipped, and radiating suburban lines extend for miles from the city, affording for five cents a pleasant and cheap excursion for the poor to the green fields and fresh air of the country.

[Ill.u.s.tration: FIG. 37.--ELECTRIC RAILWAY MOTOR, CLOSED.]

[Ill.u.s.tration: FIG. 38.--ELECTRIC RAILWAY MOTOR, OPENED.]

Figs. 37 and 38 show an electric motor used on street cars, as made by the General Electric Company. Externally it presents the appearance of some curious, uncouth, cast iron box, which, to the uninitiated, piques the curiosity, and when opened adds no explanation of its real character. In it, however, the electrician finds a most interesting combination of metal and magnetism.

[Ill.u.s.tration: FIG. 39.--ELECTRIC LOCOMOTIVE OF B. & O. TUNNEL IN BALTIMORE.]

In Fig. 39 is shown one of the most powerful electric locomotives ever constructed. It was built in 1895 by the General Electric Company for the Baltimore & Ohio Railroad, to draw trains through the long tunnel from the Camden Street Station in Baltimore, for the purpose of avoiding smoke and gas in the tunnel, which is 7,339 feet long. The locomotive weighs ninety-six tons, or twenty-five tons above the average steam locomotive. It was designed to draw 100 trains daily each way, moving pa.s.senger trains of a maximum weight of 500 tons at thirty-five miles an hour, and freight trains of 1,200 tons at fifteen miles an hour. It has two trucks, and eight drive wheels of sixty-two inches diameter. There are four motors, two to each truck, each rated at 360 horse power.

Other important applications of the electric motor are, the propelling of automobile carriages, small boats, and fish torpedoes, operating steering gear for s.h.i.+ps, pa.s.senger elevators, rock drills in mines, running printing presses, fans, sewing machines, graphophones, and in all applications where s.p.a.ce is limited and cleanliness a desideratum.

According to Mulhall there were in 1890 in the United States and Canada about 645 miles of street railway operated by electricity. This about concluded the first decade of the life of the electric railway. Some idea of the rapid increase in this field may be had by the statement of the same authority that there were in 1890, at the end of this first decade, forty-five additional electric railroads in course of construction, aggregating 512 miles of way, which nearly doubled the previous existing mileage.

In 1898 it was estimated that there were in the United States 14,000 miles of electric railroads, with a nominal capital of $1,000,000,000, and employing 170,000 men. In the same year a single electrical contract was entered into between the Third Avenue Railroad and the Union Railway Company of New York, acting as one, and the Westinghouse Electrical and Manufacturing Company, amounting to $5,000,000. This was for the electrical equipment of their respective railway lines, and is the largest electrical contract ever made. The change in equipment from other motive power to the electric is rapidly going on in all directions, and the rapid succession of trains will doubtless cause it, for pa.s.senger traffic on short lines, to eventually supersede steam.

The eighth annual report of the General Electric Company shows for the year 1899 orders received for railway and other electrical equipment amounting to $26,323,626; goods s.h.i.+pped, $22,379,463.75; profit on same, $3,805,860.18. The growth of its business from 1893 to 1899 shows the following per cent. of increase: In 1893, 36 per cent. above 1892; in 1894, 126 per cent. above 1893; in 1895, 10 per cent. above 1894; in 1896, 60 per cent. above 1895; in 1897, 60 per cent. above 1896; in 1898, 21 per cent. above 1897; in 1899, 51 per cent. above 1898.

The capitalization in electrical appliances in the United States in 1898 is estimated at $1,900,000,000, most of which is devoted to industries in which the electric motor is used. The export of electrical apparatus from this country amounts to more than three million dollars annually, and it is said that there are eight times as many electric railways in the United States as in all the rest of the world combined.

The use of electrical current in twelve princ.i.p.al cities in the United States was distributed in 1898 as follows:

Lamps, arcs, and motors in sixteen candle power equivalents.

Boston 616,000 New York 1,718,000 Chicago 1,278,000 Brooklyn 322,000 Baltimore 224,000 Philadelphia 488,000 St. Louis 303,000 San Francisco 231,000 Buffalo 125,000 Rochester 184,000 Cincinnati 201,000 New Orleans 81,000

Boston makes the largest use of electrical current in proportion to its population of any city in the world. Rochester is next. Both of these cities employ in electrical units of 16 c. p. equivalents, more than one electric lamp for every man, woman and child in their respective populations.

The dynamo and the electric motor have together wrought this great development. The dynamo takes mechanical power and converts it into electrical energy, and the electric motor takes the electrical energy and converts it back into mechanical power. Standing behind them both, however, is the steam engine, and these three afford a beautiful ill.u.s.tration of the law of correlation of forces. The force starts with the combustion of coal under the boiler of the steam engine. When carbon unites chemically with oxygen, it is an exothermic reaction that gives off heat as correlated energy. The influence of heat on the molecules of water in the boiler causes them, by repellent action, to a.s.sume the qualities of an elastic gas, and this expanding as steam drives the piston of the steam engine. The steam engine overcomes by force the resistance existing between the dynamo's field magnets and armature coil, and sets up in the latter the correlated force of an electric current, and the electric current, traveling to its remote destination by suitable conductors, enters the coils of the electric motor in reverse relation to that of the dynamo, and in producing the reverse effect between the armature and field magnets, electrical energy is converted back into mechanical power. It is not possible to obtain in the electric motor the full equivalent of the dynamo's current, nor in the dynamo the full equivalent of the steam engine's power, nor in the steam engine the full equivalent of the chemical energy in the combustion of coal. Loss by radiation, by conduction, by friction, and by electrical resistance precludes this, but while there is loss in a utilitarian sense there is no real loss, for force like matter, is indestructible, and the proof of this universal law by Joule, in 1843, const.i.tutes one of the highest triumphs of philosophy and one of the most important discoveries of the Nineteenth Century.

CHAPTER VII.

THE ELECTRIC LIGHT.

VOLTAIC ARC BY SIR HUMPHREY DAVY--THE JABLOCHKOFF CANDLE--PATENTS OF BRUSH, WESTON AND OTHERS--SEARCH LIGHTS--GROVE'S FIRST INCANDESCENT LAMP--STARR-KING LAMP--MOSES FARMER LIGHTS FIRST DWELLING WITH ELECTRIC LAMPS--SAWYER-MAN LAMP--EDISON'S INCANDESCENT LAMP-- EDISON'S THREE-WIRE SYSTEM OF CIRCUITS--STATISTICS.

The popular idea of the electric light is, that it is a very recent invention, since even the younger generation remembers when there was no such thing in general use. It will surprise many readers, then, to know that the electric light had its birth in the first decade of the Nineteenth Century. In 1809 Sir Humphrey Davy discovered that when two pieces of charcoal, which formed the terminals of a powerful voltaic battery, were separated after having been brought into contact with each other, at the moment of separation a brilliant arc of flame pa.s.sed from one piece of charcoal to the other, producing a temperature of 4,800 F., and that the intensity of the light exceeded all other known forms of light. Various improvements in the organization of devices were made for holding the two pieces of carbon, which in time a.s.sumed the form of two pencils in alignment, as in Fig. 40, and devices were provided for feeding one carbon toward the other as they burned away. Clock mechanism for thus regulating the feed was first employed, which served to automatically keep the carbons a definite distance apart, this being a necessary condition of the arc. For many years, however, the use of such a light was confined to laboratory ill.u.s.tration, for the reason that it could only be produced at great expense by a large number of voltaic batteries. Nevertheless very efficient electric lamps working by voltaic batteries were devised by Foucault, Duboscq, Deleuil and others as early as 1853. With the advent of the dynamo, however, the electric light grew rapidly and developed into conspicuous use. Even before the true dynamo was invented the magneto-electric machine was employed for producing an electric current to supply electric light. The so-called "Alliance"

generator was, in 1858, used in the South Foreland lighthouse in England to supply the arc lamps, and the beams of the electric light then, for the first time, were turned seaward as a beacon for the mariner.

[Ill.u.s.tration: FIG. 40.--SIMPLE ELECTRIC ARC LAMP.]

[Ill.u.s.tration: FIG. 41.--JABLOCHKOFF CANDLE.]

[Ill.u.s.tration: FIG. 42.--WESTON ARC LAMP.]

Among the early developments of the electric light was the Jablochkoff candle, see Fig. 41, brought out in 1877. In this device two parallel sticks of carbon G G were separated by a non-conducting layer of kaolin I, and were held in an asbestos ferrule A. Metal tubes T T connected the conducting wires F F to the carbons. The arc of flame pa.s.sed from the top of one carbon to the other, fusing the separating layer of kaolin, and the whole burned down together as a candle. This form of electric light was extensively used in Paris in 1877, and also in London, and attracted considerable attention.

[Ill.u.s.tration: FIG. 43.--ARC LAMP FEED MECHANISM.]

From the Jablochkoff candle the arc light has resumed the form of two vertically aligned carbons, and after pa.s.sing through various forms and patterns, of which the Weston lamp, Fig. 42, is a modern type, has come into such universal and conspicuous use for lighting the streets of our cities, and is so well known to-day, that but little need be said of its development, since its real character has undergone no change in principle, the improvements relating chiefly to means for regulating the feed of the carbons and maintaining them at a uniform distance apart, so as to avoid flickering. This result is obtained by automatic mechanism operated by the electric current acting upon electro-magnets, as shown in Fig. 43, in which the electro-magnets raise the upper carbon when it is too close to the lower carbon, and lower the upper carbon when the s.p.a.ce becomes too great from burning away. Among those who have contributed to the development of the arc light the names of Brush, Weston, and Thomson and Houston are most conspicuous, and the patents of Brush, No. 203,411, May 7, 1878, and No. 212,183, Feb. 11, 1879, and Weston, No. 285,451, Sept. 25, 1883, are the most representative developments.

[Ill.u.s.tration: FIG. 44.--NINE THOUSAND CANDLE POWER ARC LAMP.]

The applications of the arc light have been brilliant beyond the dreams of the most sanguine inventor. In the ill.u.s.trations number 44, 45 and 46, is shown a gigantic electric light beacon manufactured by Henry Lepaute, of Paris, and first exhibited in this country at the Chicago World's Fair, in 1893. It consists of two great lenses, each nine feet in diameter, between which, in their focus, is placed a 9,000 candle power arc light. The great lantern, Fig. 45, is carried by a vertical shaft, which terminates at its lower end in a hollow drum, which latter floats in a bath of mercury. Although the weight is estimated at several tons, so sensitive is its poise on the mercury that the enormous lantern may be easily rotated by the pressure of one's finger. Each lens consists of concentric segments, see Fig. 46, 190 in number, surrounding a central disk, which together cause the rays to issue in parallel lines. The nine-foot beam of light thus projected is of 90,000,000 candle power, and if placed at a sufficient alt.i.tude to avoid the curvature of the earth's surface, its light would be visible at the range of 146.9 nautical miles.

[Ill.u.s.tration: FIG. 45.--NINETY MILLION CANDLE POWER BIVALVE LENS.]

[Ill.u.s.tration: FIG. 46.--FRONT VIEW OF LENS.]

Better known to the patrons of our excursion boats and the visitors to our splendid battles.h.i.+ps, are the electric search lights. The greatest example of all search lights, however, is not to be found on the sea, but in the picturesque alt.i.tudes of the Sierra Madres in Southern California. At the summit of Mount Lowe, in the neighborhood of Pasadena, is the largest search light in the world, shown in ill.u.s.tration, Fig. 48. It is of 3,000,000 candle power, stands eleven feet high, and its total weight is 6,000 pounds. Its light may be seen for 150 miles out on the ocean, and as its powerful beam is thrown from mountain top to mountain top hundreds of miles apart, it adds the illumination of art to the sublimity of nature, and seems a fitting jewel to this lofty crown of Mother Earth.

[Ill.u.s.tration: FIG. 47.--SEARCH LIGHT WITH MACHINE GUN REPELLING NIGHT ATTACK OF TORPEDO BOAT.]