History Of Electric Light - free ebook by Henry Schroeder

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History Of Electric Light

Henry Schroeder

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HISTORY OF ELECTRIC LIGHT

HISTORY OF ELECTRIC LIGHT

BY HENRY SCHROEDER Harrison, New Jersey FOR THE INCREASE AND DIFFVSION OF KNOWLEDGE AMONG MEN SMITHSONIAN INSTITVTION WASHINGTON 1846 ( Publication 2717 ) CITY OF WASHINGTON PUBLISHED BY THE SMITHSONIAN INSTITUTION AUGUST 15, 1923 The Lord Baltimore Press BALTIMORE, MD., U. S. A....

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FOREWORD

FOREWORD

In the year 1884 a Section of Transportation was organized in the United States National Museum for the purpose of preparing and assembling educational exhibits of a few objects of railroad machinery which had been obtained both from the Centennial Exhibition held in Philadelphia in 1876 and still earlier as incidentals to ethnological collections, and to secure other collections relating to the railway industry. From this beginning the section was expanded to include the whole field of engineer

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CHRONOLOGY OF ELECTRIC LIGHT

CHRONOLOGY OF ELECTRIC LIGHT

1800—Allesandro Volta demonstrated his discovery that electricity can be generated by chemical means. The Volt , the unit of electric pressure, is named in his honor for this discovery of the electric battery. 1802—Sir Humphry Davy demonstrated that electric current can heat carbon and strips of metal to incandescence and give light. 1809—Sir Humphry Davy demonstrated that current will give a brilliant flame between the ends of two carbon pencils which are first allowed to touch each other and t

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HISTORY OF ELECTRIC LIGHT

HISTORY OF ELECTRIC LIGHT

By HENRY SCHROEDER, HARRISON, NEW JERSEY....

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EARLY RECORDS OF ELECTRICITY AND MAGNETISM

EARLY RECORDS OF ELECTRICITY AND MAGNETISM

About twenty-five centuries ago, Thales, a Greek philosopher, recorded the fact that if amber is rubbed it will attract light objects. The Greeks called amber “elektron,” from which we get the word “electricity.” About two hundred and fifty years later, Aristotle, another Greek philosopher, mentioned that the lodestone would attract iron. Lodestone is an iron ore (Fe 3 O 4 ), having magnetic qualities and is now called magnetite. The word “magnet” comes from the fact that the best specimens of l

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MACHINES GENERATING ELECTRICITY BY FRICTION

MACHINES GENERATING ELECTRICITY BY FRICTION

Otto Von Guericke was mayor of the city of Magdeburg as well as a philosopher. About 1650 he made a machine consisting of a ball of sulphur mounted on a shaft which could be rotated. Electricity was generated when the hand was pressed against the globe as it rotated. He also discovered that electricity could be conducted away from the globe by a chain and would appear at the other end of the chain. Von Guericke also invented the vacuum air pump. In 1709, Francis Hawksbee, an Englishman, made a s

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THE LEYDEN JAR

THE LEYDEN JAR

The thought came to Von Kleist, Bishop of Pomerania, Germany, about 1745, that electricity could be stored. The frictional machines generated so small an amount of electricity (though, as is now known, at a very high pressure—several thousand volts) that he thought he could increase the quantity by storing it. Knowing that glass was an insulator and water a conductor, he filled a glass bottle partly full of water with a nail in the cork to connect the machine with the water. Holding the bottle i

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ELECTRICITY GENERATED BY CHEMICAL MEANS

ELECTRICITY GENERATED BY CHEMICAL MEANS

Luigi Galvani was an Italian scientist. About 1785, so the story goes, his wife was in delicate health, and some frog legs were being skinned to make her a nourishing soup. An assistant holding the legs with a metal clamp and cutting the skin with a scalpel, happened to let the clamp and scalpel touch each other. To his amazement the frog legs twitched. Galvani repeated the experiment many times by touching the nerve with a metal rod and the muscle with a different metal rod and allowing the rod

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IMPROVEMENT OF VOLTA’S BATTERY

IMPROVEMENT OF VOLTA’S BATTERY

It was early suggested that sheets of silver and zinc be soldered together back to back and that a trough be divided into cells by these bimetal sheets being put into grooves cut in the sides and bottom of the trough. This is the reason why one unit of a battery is called a “cell.” It was soon found that a more powerful cell could be made if copper, zinc and dilute sulphuric acid were used. The zinc is dissolved by the acid forming zinc sulphate and hydrogen gas, thus: Zn + H 2 SO 4 = ZnSO 4 + H

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DAVY’S DISCOVERIES

DAVY’S DISCOVERIES

Sir Humphry Davy was a well-known English chemist, and with the aid of powerful batteries constructed for the Royal Institution in London, he made numerous experiments on the chemical effects of electricity. He decomposed a number of substances and discovered the elements boron, potassium and sodium. He heated strips of various metals to incandescence by passing current through them, and showed that platinum would stay incandescent for some time without oxidizing. This was about 1802. In the ear

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RESEARCHES OF OERSTED, AMPÈRE, SCHWEIGGER AND STURGEON

RESEARCHES OF OERSTED, AMPÈRE, SCHWEIGGER AND STURGEON

Hans Christian Oersted was a professor of physics at the University of Copenhagen in Denmark. One day in 1819, while addressing his students, he happened to hold a wire, through which current was flowing, over a large compass. To his surprise he saw the compass was deflected from its true position. He promptly made a number of experiments and discovered that by reversing the current the compass was deflected in the opposite direction. Oersted announced his discovery in 1820. André Marie Ampère w

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OHM’S LAW

OHM’S LAW

Georg Simon Ohm was born in Bavaria, the oldest son of a poor blacksmith. With the aid of friends he went to college and became a teacher. It had been shown that the rate of transfer of heat from one end to the other of a metal bar is proportional to the difference of temperature between the ends. About 1825, Ohm, by analogy and experiment, found that the current in a conductor is proportional to the difference of electric pressure (voltage) between its ends. He further showed that with a given

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INVENTION OF THE DYNAMO

INVENTION OF THE DYNAMO

Michael Faraday was an English scientist. Born of parents in poor circumstances, he became a bookbinder and studied books on electricity and chemistry. He finally obtained a position as laboratory assistant to Sir Humphry Davy helping him with his lectures and experiments. He also made a number of experiments himself and succeeded in liquifying chlorine gas for which he was elected to a Fellowship in the Royal Institution in 1824. Following up Oersted’s and Ampère’s work, he endeavored to find t

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DANIELL’S BATTERY

DANIELL’S BATTERY

Daniell’s Cell, 1836. Daniell invented a battery consisting of zinc, copper and copper sulphate. Later the porous cup was dispensed with, which was used to keep the sulphuric acid formed separate from the solution of copper sulphate, the two liquids then being kept apart by their difference in specific gravity. It was then called the Gravity Battery and for years was used in telegraphy. It was soon discovered that if the zinc electrode were rubbed with mercury (amalgamated), the local action wou

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GROVE’S BATTERY

GROVE’S BATTERY

Sir William Robert Grove, an English Judge and scientist, invented a cell in 1838 consisting of a platinum electrode in strong nitric acid in a porous earthenware jar. This jar was put in dilute sulphuric acid in a glass jar in which there was an amalgamated zinc plate for the other electrode. This had an open circuit voltage of about 1.9 volts. The porous jar was used to prevent the nitric acid from attacking the zinc. The nitric acid was used for the purpose of combining with the hydrogen gas

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GROVE’S DEMONSTRATION OF INCANDESCENT LIGHTING

GROVE’S DEMONSTRATION OF INCANDESCENT LIGHTING

In 1840 Grove made an experimental lamp by attaching the ends of a coil of platinum wire to copper wires, the lower parts of which were well varnished for insulation. The platinum wire was covered by a glass tumbler, the open end set in a glass dish partly filled with water. This prevented draughts of air from cooling the incandescent platinum, and the small amount of oxygen of the air in the tumbler reduced the amount of oxidization of the platinum that would otherwise occur. With current suppl

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GRENET BATTERY

GRENET BATTERY

It was discovered that chromic anhydride gives up oxygen easier than nitric acid and consequently if used would give a higher voltage than Grove’s nitric acid battery. It also has the advantage of a lesser tendency to attack zinc directly if it happens to come in contact with it. Grenet developed a cell having a liquid consisting of a mixture of potassium bichromate (K 2 Cr 2 O 7 ) and sulphuric acid. A porous cell was therefore not used to keep the two liquids apart. This had the advantage of r

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DE MOLEYNS’ INCANDESCENT LAMP

DE MOLEYNS’ INCANDESCENT LAMP

Frederick De Moleyns, an Englishman, has the honor of having obtained the first patent on an incandescent lamp. This was in 1841 and his lamp was quite novel. It consisted of a spherical glass globe, in the upper part of which was a tube containing powdered charcoal. This tube was open at the bottom inside the globe and through it ran a platinum wire, the end below the tube being coiled. Another platinum wire coiled at its upper end came up through the lower part of the globe but did not quite t

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EARLY DEVELOPMENTS OF THE ARC LAMP

EARLY DEVELOPMENTS OF THE ARC LAMP

It had been found that most of the light of the arc came from the tip of the positive electrode, and that the charcoal electrodes were rapidly consumed, the positive electrode about twice as fast as the negative. Mechanisms were designed to take care of this, together with devices to start the arc by allowing the electrodes to touch each other and then pulling them apart the proper distance. This distance varied from one-eighth to three-quarters of an inch. In 1840 Bunsen, the German chemist who

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JOULE’S LAW

JOULE’S LAW

Joule was an Englishman, and in 1842 began investigating the relation between mechanical energy and heat. He first showed that, by allowing a weight to drop from a considerable height and turn a paddle wheel in water, the temperature of the water would increase in relation to the work done in turning the wheel. It is now known that 778 foot-pounds (1 lb. falling 778 feet, 10 lbs. falling 77.8 feet or 778 lbs. falling one foot, etc.) is the mechanical equivalent of energy equal to raising one pou

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STARR’S INCANDESCENT LAMP

STARR’S INCANDESCENT LAMP

Starr’s Incandescent Lamp, 1845. This consisted of a short carbon pencil operating in the vacuum above a column of mercury. J. W. Starr, an American, of Cincinnati, Ohio, assisted financially by Peabody, the philanthropist, went to England where he obtained a patent in 1845 on the lamps he had invented, although the patent was taken out under the name of King, his attorney. One is of passing interest only. It consisted of a strip of platinum, the active length of which could be adjusted to fit t

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OTHER EARLY INCANDESCENT LAMPS

OTHER EARLY INCANDESCENT LAMPS

Staite’s Incandescent Lamp, 1848. The burner was of platinum and iridium. Roberts’ Incandescent Lamp, 1852. It had a graphite burner operating in vacuum. In 1848 W. E. Staite, who two years previously had made an arc lamp, invented an incandescent lamp. This consisted of a platinum-iridium burner in the shape of an inverted U, covered by a glass globe. It had a thumb screw for a switch, the whole device being mounted on a bracket which was used for the return wire. E. C. Shepard, another English

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FURTHER ARC LAMP DEVELOPMENTS

FURTHER ARC LAMP DEVELOPMENTS

During the ten years, 1850 to 1860, several inventors developed arc lamp mechanisms. Among them was M. J. Roberts, who had invented the graphite incandescent lamp. In Roberts’ arc lamp, which he patented in 1852, the lower carbon was stationary. The upper carbon fitted snugly into an iron tube. In the tube was a brass covered iron rod, which by its weight could push the upper carbon down the tube so the two carbons normally were in contact. An electro-magnet in series with the arc was so located

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DEVELOPMENT OF THE DYNAMO, 1840–1860

DEVELOPMENT OF THE DYNAMO, 1840–1860

During the first few years after 1840 the dynamo was only a laboratory experiment. Woolrich devised a machine which had several pairs of magnets and double the number of coils in order to make the current obtained less pulsating. Wheatstone in 1845 patented the use of electro-magnets in place of permanent magnets. Brett in 1848 suggested that the current, generated in the coils, be allowed to flow through a coil surrounding each permanent magnet to further strengthen the magnets. Pulvermacher in

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THE FIRST COMMERCIAL INSTALLATION OF AN ELECTRIC LIGHT

THE FIRST COMMERCIAL INSTALLATION OF AN ELECTRIC LIGHT

In 1862 a Serrin type of arc lamp was installed in the Dungeness lighthouse in England. Current was supplied by a dynamo made by the Alliance Company, which had been originally designed in 1850 by Nollet, a professor of Physics in the Military School in Brussels. Nollet’s original design was of a dynamo having several rows of permanent magnets mounted radially on a stationary frame, with an equal number of bobbins mounted on a shaft which rotated and had a commutator so direct current could be o

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FURTHER DYNAMO DEVELOPMENTS

FURTHER DYNAMO DEVELOPMENTS

In the summer of 1886 Sir Charles Wheatstone constructed a self-excited machine on the principle of using the residual magnetism in the field poles to set up a feeble current in the armature which, passing through the field coils, gradually strengthened the fields until they built up to normal strength. It was later found that this idea had been thought of by an unknown man, being disclosed by a clause in a provisional 1858 English patent taken out by his agent. Wheatstone’s machine was shown to

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RUSSIAN INCANDESCENT LAMP INVENTORS

RUSSIAN INCANDESCENT LAMP INVENTORS

In 1872 Lodyguine, a Russian scientist, made an incandescent lamp consisting of a “V” shaped piece of graphite for a burner, which operated in nitrogen gas. He lighted the Admiralty Dockyard at St. Petersburg with about two hundred of these lamps. In 1872 the Russian Academy of Sciences awarded him a prize of 50,000 rubles (a lot of real money at that time) for his invention. A company with a capital of 200,000 rubles (then equal to about $100,000) was formed but as the lamp was so expensive to

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THE JABLOCHKOFF “CANDLE”

THE JABLOCHKOFF “CANDLE”

Paul Jablochkoff was a Russian army officer and an engineer. In the early seventies he came to Paris and developed a novel arc light. This consisted of a pair of carbons held together side by side and insulated from each other by a mineral known as kaolin which vaporized as the carbons were consumed. There was no mechanism, the arc being started by a thin piece of carbon across the tips of the carbons. Current burned this bridge, starting the arc. The early carbons were about five inches long, a

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COMMERCIAL INTRODUCTION OF THE DIFFERENTIALLY CONTROLLED ARC LAMP

COMMERCIAL INTRODUCTION OF THE DIFFERENTIALLY CONTROLLED ARC LAMP

About the same time Lontin, a Frenchman, improved Serrin’s arc lamp mechanism by the application of series and shunt magnets. This is the differential principle which was invented by Lacassagne and Thiers in 1855 but which apparently had been forgotten. Several of these lamps were commercially installed in France beginning with 1876....

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ARC LIGHTING IN THE UNITED STATES

ARC LIGHTING IN THE UNITED STATES

Wallace-Farmer Arc Lamp, 1875. This “differentially controlled” arc lamp consisted of two slabs of carbon between which the arc played. In the original lamp the carbon slabs were mounted on pieces of wood held in place by bolts, adjustment being made by hitting the upper carbon slab with a hammer. This lamp is in the collection of the Smithsonian Institution. Wallace-Farmer Dynamo, 1875. This was the first commercial dynamo used in the United States for arc lighting. This dynamo is in the collec

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OTHER AMERICAN ARC LIGHT SYSTEMS

OTHER AMERICAN ARC LIGHT SYSTEMS

Thomson-Houston Arc Lamp, 1878. This is an early model with a single pair of carbons. Thomson Double Carbon Arc Lamp. This later model, having two pairs of carbons, was commercially used for many years. This lamp is in the collection of the Smithsonian Institution. Beginning with about 1880, several arc light systems were developed. Among these were the Vanderpoele, Hochausen, Waterhouse, Maxim, Schuyler and Wood. The direct current carbon arc is inherently more efficient than the alternating cu

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“SUB-DIVIDING THE ELECTRIC LIGHT”

“SUB-DIVIDING THE ELECTRIC LIGHT”

While the arc lamp was being commercially established, it was at once seen that it was too large a unit for household use. Many inventors attacked the problem of making a smaller unit, or, as it was called, “sub-dividing the electric light.” In the United States there were four men prominent in this work: William E. Sawyer, Moses G. Farmer, Hiram S. Maxim and Thomas A. Edison. These men did not make smaller arc lamps but all attempted to make an incandescent lamp that would operate on the arc ci

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EDISON’S INVENTION OF A PRACTICAL INCANDESCENT LAMP

EDISON’S INVENTION OF A PRACTICAL INCANDESCENT LAMP

Edison began the study of the problem in the spring of 1878. He had a well-equipped laboratory at Menlo Park, New Jersey, with several able assistants and a number of workmen, about a hundred people all told. He had made a number of well-known inventions, among which were the quadruplex telegraph whereby four messages could be sent simultaneously over one wire, the carbon telephone transmitter without which Bell’s telephone receiver would have been impracticable, and the phonograph. All of these

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EDISON’S THREE-WIRE SYSTEM

EDISON’S THREE-WIRE SYSTEM

The distance at which current can be economically delivered at 110 volts pressure is limited, as will be seen from a study of Ohm’s law. The loss of power in the distributing wires is proportional to the square of the current flowing. If the voltage be doubled, the amount of current is halved, for a given amount of electric power delivered, so that the size of the distributing wires can then be reduced to one-quarter for a given loss in them. At that time (1881) it was impossible to make 220-vol

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DEVELOPMENT OF THE ALTERNATING CURRENT CONSTANT POTENTIAL SYSTEM

DEVELOPMENT OF THE ALTERNATING CURRENT CONSTANT POTENTIAL SYSTEM

The distance that current can be economically distributed, as has been shown, depends upon the voltage used. If, therefore, current could be sent out at a high voltage and the pressure brought down to that desired at the various points to which it is distributed, such distribution could cover a much greater area. Lucien Gaulard was a French inventor and was backed by an Englishman named John D. Gibbs. About 1882 they patented a series alternating-current system of distribution. They had invented

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INCANDESCENT LAMP DEVELOPMENTS, 1884–1894

INCANDESCENT LAMP DEVELOPMENTS, 1884–1894

In 1884 the ring of plaster around the top of the base was omitted; in 1886 an improvement was made by pasting the filament to the leading-in wires with a carbon paste instead of the electro-plating method; and in 1888 the length of the base was increased so that it had more threads. Several concerns started making incandescent lamps, the filaments being made by carbonizing various substances. “Parchmentized” thread consisted of ordinary thread passed through sulphuric acid. “Tamadine” was cellu

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THE EDISON “MUNICIPAL” STREET LIGHTING SYSTEM

THE EDISON “MUNICIPAL” STREET LIGHTING SYSTEM

Edison “Municipal” System, 1885. High voltage direct current was generated, several circuits operating in multiple, three ampere lamps burning in series on each circuit. Photograph courtesy of Association of Edison Illuminating Companies. The arc lamp could not practically be made in a unit smaller than the so-called “1200 candlepower” (6.6 ampere) or “half” size, which really gave about 350 spherical candlepower. A demand therefore arose for a small street lighting unit, and Edison designed his

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THE SHUNT BOX SYSTEM FOR SERIES INCANDESCENT LAMPS

THE SHUNT BOX SYSTEM FOR SERIES INCANDESCENT LAMPS

Shunt Box System, 1887. Lamps were burned in series on a high voltage alternating current, and when a lamp burned out all the current then went through its “shunt box,” a reactance coil in multiple with each lamp. Soon after the commercial development of the alternating current constant potential system, a scheme was developed to permit the use of lamps in series on such circuits without the necessity for short circuiting a lamp should it burn out. A reactance, called a “shunt box” and consistin

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THE ENCLOSED ARC LAMP

THE ENCLOSED ARC LAMP

Up to 1893 the carbons of an arc lamp operated in the open air, so that they were rapidly consumed, lasting from eight to sixteen hours depending on their length and thickness. Louis B. Marks, an American, found that by placing a tight fitting globe about the arc, the life of the carbons was increased ten to twelve times. This was due to the restricted amount of oxygen of the air in the presence of the hot carbon tips and thus retarded their consumption. The amount of light was somewhat decrease

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THE FLAME ARC LAMP

THE FLAME ARC LAMP

About 1844 Bunsen investigated the effect of introducing various chemicals in the carbon arc. Nothing was done, however, until Bremer, a German, experimented with various salts impregnated in the carbon electrodes. In 1898 he produced the so-called flame arc, which consisted of carbons impregnated with calcium fluoride. This gave a brilliant yellow light most of which came from the arc flame, and practically none from the carbon tips. The arc operated in the open air and produced smoke which con

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THE CONSTANT CURRENT TRANSFORMER FOR SERIES CIRCUITS

THE CONSTANT CURRENT TRANSFORMER FOR SERIES CIRCUITS

About 1900 the constant current transformer was developed by Elihu Thomson. This transforms current taken from a constant potential alternating current circuit into a constant alternating current for series circuits, whose voltage varies with the load on the circuit. The transformer has two separate coils; the primary being stationary and connected to the constant potential circuit and the secondary being movable and connected to the series circuit. The weight of the secondary coil is slightly u

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ENCLOSED SERIES ALTERNATING CURRENT ARC LAMPS

ENCLOSED SERIES ALTERNATING CURRENT ARC LAMPS

The simplicity of the constant current transformer soon drove the constant direct-current dynamo from the market. An enclosed arc lamp was therefore developed for use on alternating constant current. Two sizes of lamps were made; one for 6.6 amperes consuming 450 watts and having an efficiency of about 4½ lumens per watt, and the other 7.5 amperes, 480 watts and 5 l-p-w (clear glassware). These lamps soon superseded the direct current series arcs. They have now been superseded by the more effici

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SERIES INCANDESCENT LAMPS ON CONSTANT CURRENT TRANSFORMERS

SERIES INCANDESCENT LAMPS ON CONSTANT CURRENT TRANSFORMERS

Series incandescent lamps were made for use on constant current transformers superseding the “Municipal” and “Shunt Box” systems. The large Edison, now called the Mogul Screw base, was adopted and the short circuiting film cut-out was removed from the base and placed between prongs attached to the socket. Series Incandescent Lamp Socket with Film Cutout, 1900. The “Large Edison,” now called Mogul Screw, base was standardized and the short circuiting device put on the socket terminals. The “Large

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THE NERNST LAMP

THE NERNST LAMP

Dr. Walther Nernst, of Germany, investigating the rare earths used in the Welsbach mantle, developed an electric lamp having a burner, or “glower” as it was called, consisting of a mixture of these oxides. The main ingredient was zirconia, and the glower operated in the open air. It is a non-conductor when cold, so had to be heated before current would flow through it. This was accomplished by an electric heating coil, made of platinum wire, located just above the glower. As the glower became he

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THE COOPER-HEWITT LAMP

THE COOPER-HEWITT LAMP

In 1860 Way discovered that if an electric circuit was opened between mercury contacts a brilliant greenish colored arc was produced. Mercury was an expensive metal and as the carbon arc seemed to give the most desirable results, nothing further was done for many years until Dr. Peter Cooper Hewitt, an American, began experimenting with it. He finally produced an arc in vacuum in a one-inch glass tube about 50 inches long for 110 volts direct current circuits, which was commercialized in 1901. T

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THE LUMINOUS OR MAGNETITE ARC LAMP

THE LUMINOUS OR MAGNETITE ARC LAMP

About 1901 Dr. Charles P. Steinmetz, Schenectady, N. Y., studied the effect of metallic salts in the arc flame. Dr. Willis R. Whitney, also of Schenectady, and director of the research laboratory of the organization of which Dr. Steinmetz is the consulting engineer, followed with some further work along this line. The results of this work were incorporated in a commercial lamp called the magnetite arc lamp, through the efforts of C. A. B. Halvorson, Jr., at Lynn, Mass. The negative electrode con

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MERCURY ARC RECTIFIER FOR MAGNETITE ARC LAMPS

MERCURY ARC RECTIFIER FOR MAGNETITE ARC LAMPS

Mercury Arc Rectifier Tube for Series Magnetite Arc Lamps, 1902. The mercury arc converted the alternating constant current into direct current required by the magnetite lamp. As the magnetite arc requires direct current for its operation, the obvious way to supply a direct constant current for series circuits is to rectify, by means of the mercury arc, the alternating current obtained from a constant current transformer. The terminals of the movable secondary coil of the constant current transf

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INCANDESCENT LAMP DEVELOPMENTS, 1894–1904

INCANDESCENT LAMP DEVELOPMENTS, 1894–1904

With the development of a waterproof base in 1900, by the use of a waterproof cement instead of plaster of Paris to fasten the base to the bulb, porcelain at first and later glass being used to insulate the terminals of the base from each other, lamps could be exposed to the weather and give good results. Electric sign lighting therefore received a great stimulus, and lamps as low as 2 candlepower for 110 volts were designed for this purpose. Carbon lamps with concentrated filaments were also ma

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THE MOORE TUBE LIGHT

THE MOORE TUBE LIGHT

Geissler, a German, discovered sixty odd years ago, that a high voltage alternating current would cause a vacuum tube to glow. This light was similar to that obtained by Hawksbee over two hundred years ago. Geissler obtained his high voltage alternating current by a spark coil, which consisted of two coils of wire mounted on an iron core. Current from a primary battery passed through the primary coil, and this current was rapidly interrupted by a vibrator on the principle of an electric bell. Th

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THE OSMIUM LAMP

THE OSMIUM LAMP

Dr. Auer von Welsbach, the German scientist who had produced the Welsbach gas mantle, invented an incandescent electric lamp having a filament of the metal osmium. It was commercially introduced in Europe in 1905 and a few were sold, but it was never marketed in this country. It was generally made for 55 volts, two lamps to burn in series on 110-volt circuits, gave about 25 candlepower and had an initial efficiency of about 5½ lumens per watt. It had a very fair maintenance of candlepower during

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THE GEM LAMP

THE GEM LAMP

Dr. Willis R. Whitney, of Schenectady, N. Y., had invented an electrical resistance furnace. This consisted of a hollow carbon tube, packed in sand, through which a very heavy current could be passed. This heated the tube to a very high temperature, the sand preventing the tube from oxidizing, so that whatever was put inside the tube could be heated to a very high heat. Among his various experiments, he heated some carbon filaments and found that the high temperature changed their resistance “ch

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THE TANTALUM LAMP

THE TANTALUM LAMP

Tantalum Lamp, 1906. The tantalum filament could be operated at 50 per cent greater efficiency than that of the regular carbon incandescent lamp. This lamp is in the exhibit of Edison lamps in the Smithsonian Institution. Dr. Werner von Bolton, a German physicist, made an investigation of various materials to see if any of them were more suitable than carbon for an incandescent-lamp filament. After experimenting with various metals, tantalum was tried. Tantalum had been known to science for abou

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INVENTION OF THE TUNGSTEN LAMP

INVENTION OF THE TUNGSTEN LAMP

Alexander Just and Franz Hanaman in 1902 were laboratory assistants to the Professor of Chemistry in the Technical High School in Vienna. Just was spending his spare time in another laboratory in Vienna, attempting to develop a boron incandescent lamp. In August of that year he engaged Hanaman to aid him in his work. They conceived the idea of making a lamp with a filament of tungsten and for two years worked on both lamps. The boron lamp turned out to be a failure. Their means were limited; Han

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DRAWN TUNGSTEN WIRE

DRAWN TUNGSTEN WIRE

After several years of patient experiment, Dr. William D. Coolidge in the research laboratory of a large electrical manufacturing company at Schenectady, N. Y., invented a process for making tungsten ductile, a patent for which was obtained in December, 1913. Tungsten had heretofore been known as a very brittle metal, but by means of this process it became possible to draw it into wire. This greatly simplified the manufacture of lamps and enormously improved their strength. Such lamps were comme

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THE QUARTZ MERCURY VAPOR ARC LAMP

THE QUARTZ MERCURY VAPOR ARC LAMP

By putting a mercury arc in a tube made of quartz instead of glass, it can be operated at a much higher temperature and thereby obtain a greater efficiency. Such a lamp, however, is still largely deficient in red rays, and it gives out a considerable amount of ultra-violet rays. These ultra-violet rays will kill bacteria and the lamp is being used to a certain extent for such purpose as in the purification of water. These rays are very dangerous to the eyes, but they are absorbed by glass, so as

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THE GAS-FILLED TUNGSTEN LAMP

THE GAS-FILLED TUNGSTEN LAMP

The higher the temperature at which an incandescent lamp filament can be operated, the more efficient it becomes. The limit in temperature is reached when the material begins to evaporate rapidly, which blackens the bulb. The filament becoming thinner more quickly, thus rupturing sooner, shortens the life. If, therefore, the evaporating temperature can by some means be slightly raised, the efficiency will be greatly improved. This was accomplished by Dr. Irving Langmuir in the research laborator

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TYPES AND SIZES OF TUNGSTEN LAMPS NOW MADE

TYPES AND SIZES OF TUNGSTEN LAMPS NOW MADE

There are about two hundred different types and sizes of tungsten filament lamps now standard for various kinds of lighting service. For 110-volt service, lamps are made in sizes from 10 to 1000 watts. Of the smaller sizes, some are made in round and tubular-shaped bulbs for ornamental lighting. In addition there are the candelabra lamps used in ornamental fixtures. Twenty-five- to five hundred-watt lamps are made with bulbs of special blue glass to cut out the excess of red and yellow rays and

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STANDARD VOLTAGES

STANDARD VOLTAGES

Mention has been made of 110-volt service, 220-volt service, etc. In the days of the carbon incandescent lamp it was impossible to manufacture all lamps for an exact predetermined voltage. The popular voltage was 110, so lighting companies were requested in a number of instances to adjust their service to some voltage other than 110. They were thus able to utilize the odd voltage lamps manufactured, and this produced a demand for lamps of various voltages from 100 to 130. Arc lamps had a resista

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COST OF INCANDESCENT ELECTRIC LIGHT

COST OF INCANDESCENT ELECTRIC LIGHT

In the early ’80’s current was expensive, costing a consumer on the average about twenty cents per kilowatt hour. The cost has gradually come down and the general average rate for which current is sold for lighting purposes is now about 4½ cents. During the period 1880 to 1905 the average efficiency of carbon lamps throughout their life increased from about one to over 2¾ lumens per watt and their list price decreased from one dollar to twenty cents. The average amount of light obtained for one

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STATISTICS REGARDING THE PRESENT DEMAND FOR LAMPS

STATISTICS REGARDING THE PRESENT DEMAND FOR LAMPS

In the United States there are about 350 million incandescent and about two hundred thousand magnetite arc lamps now (1923) in use. They are increasing about 10 per cent each year. The annual demand for incandescent lamps for renewals and new installations is over 200 millions, exclusive of miniature lamps. The use of incandescent lamps in all other countries put together is about equal that in the U. S. The average candlepower of standard lighting lamps has increased from 16, which prevailed du

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SELECTED BIBLIOGRAPHY

SELECTED BIBLIOGRAPHY

Alglave and Boulard , “The Electric Light,” translated by T. O’Connor Sloane, edited by C. M. Lungren, D. Appleton &amp; Co., New York, 1884. Barham, G. Basil , “The Development of the Incandescent Electric Lamp,” Scott Greenwood &amp; Son, London, 1912. Dredge, James , “Electric Illumination,” 2 vols., John Wiley &amp; Sons, New York, 1882. Durgin, William A. , “Electricity—Its History and Development,” A. C. McClurg &amp; Co., Chicago, 1912. Dyer &amp; Martin , “Edison, His

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