came into almost universal use in the United States.
1891 ALMON B. STROWGER ( ) of Kansas City, Mis-
souri, patents an automatic telephone exchange whereby a
person at one telephone can make connections with any other
telephone in the system by aid of automatic switches at the
central office and without the assistance of an operator. The
Strowger Automatic Telephone Exchange is organized to
develop, manufacture, and install this system.
1891 The American Institute of Electrical Engineers appoints a
committee on Units and Standards with special reference to
the study of magnetic circuit units.
1891 "Electricity," a weekly magazine, begins publication in New
York in July.
1891 Steinmetz (see 1889) publishes his first paper on the law of
1891 The first patent, No. 463,802, on the Ward Leonard System of
Control is issued November 24. This is the first patent on
the methods of control that are still used on elevators, mine
hoists, steel rolling mills, many marine applications, and so on.
1892 Westinghouse (see 1886) originates the rotary .converter,
builds a successful nonarcing lighting arrester, produces
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the polyphase system of alternating-current generation and
1892 NATHAN B. STUBBLEFIELD ( ) demonstrates a
radio broadcast. In 1902 he gave a public exhibition of his
invention in Fairmont Park, Philadelphia, his voice being
heard a mile from the transmitter. He was granted Patent
No. 887,357, May 12, 1908.
1892 The Westinghouse Electric Manufacturing Company exhibits
its first "stopper lamp" two pieces of glass and a soft iron
1892 The Baltimore & Ohio Railroad becomes the first steam railway
in the United States to use electric locomotives and power
equipment. The first electrification covers about three miles
of track, including a tunnel, through Baltimore. The first trip
over the electrified line was made in 1894 and actual service
began August 4, 1895.
1892 Alexander Graham Bell (see 1871) opens a New York to Chi-
cago telephone circuit in preparation for the Chicago World's
1892 J. B. MCDONALD, president of the American Battery Com-
pany, of Chicago, buys William Morrison's design for an
electrically operated automobile (.see 1891).
1892 The "Electrical Worker," a monthly magazine, begins publica-
tion in St. Louis, Missouri.
1892 The Strowger Automatic Telephone Exchange, manufactured
and installed in La Porte, Indiana, is the first automatic tele-
phone switchboard to be used commercially.
1892 The first automatic or push-button controlled elevators are
1892 The General Electric Company is organized and incorporated
April 15 by a consolidation of the Edison General Electric Co.
(formerly the Edison and Sprague interests) and the Thom-
son-Houston Co. Charles Proteus Steinmetz leaves the Eicke-
meyer Co. (see 1889) to join the new General Electric Com-
pany and develops a system of mathematics for the solution
of alternating-current problems.
1892 Additional lighting of the Statue of Liberty in New York
Harbor with incandescent lamps, in addition to arc lamps,
is installed as part of the Columbian celebration (see 1885).
1893 Westinghouse starts building three 5,000 horsepower, alter-
nating-current generators for Niagara Falls powerhouse. The
generators are five times as large as the largest hitherto
and the switches, instruments, busbars, and transmission are
all unprecedented 2,000 volt, 2 phase, 25 cycles.
1893 The first code covering the installation of electrical equipment
is printed under the title of "Rules & Requirements for the
Installation of Electric Light & Power," as revised and codi-
fied by the Underwriters International Electrical Association.
This is the beginning of the National Electrical Code.
1893 Open and concealed work, wooden molding, and conduit wiring
is recognized by the National Electrical Code. The use of con-
duit was limited to what was later known as "lined" conduit.
1893 De Laval designs, builds, and has in operation at the Colum-
bian world's fair in Chicago the first high-speed, geared steam
turbine in the United States. The turbine develops 10 horse-
power at a turbine speed of 24,000 rpm, speed of generator
2,400 rpm using a ten-to-one gear reduction.
1893 The Fourth International Electrical Congress, notable in the
history of electrical units, is held in Chicago. Its decisions
in reference to electrical units and standards form the basis
of much legislation in all parts of the world. Prior to this
Congress, changes in the international electrical units might
not have been possible because not many countries had enacted
laws concerning electrical standards.
1893 The external shunt type of ammeter is invented by Dr. Ed-
ward Weston (see 1872). The shunt in connection with a
millivoltmeter was first used especially for measuring high
currents. A patent was issued on Weston standard cell and
later was dedicated to the public. The standard cell is used
as a reference basis for the "volt" and is found in every stan-
dardizing laboratory in the world.
1893 The World's Columbian Exposition is held in Chicago and
gives the electrical industry an opportunity to show the prog-
ress it has made in electrical generation and lighting up to
this time. The Westinghouse Company, who is awarded the
contract for lighting the exposition, demonstrates a complete
polyphase power system in operation using twelve 1,000 horse-
power, 2,200 volt, 60 cycle, 2 phase generators, the largest
alternating-current machines in America. In the electrical
installation 483,882 feet of insulated copper conductors, rang-
ing from to No. 6, B & S Gauge, are used for the primary
service. It also requires 146,749 feet of duct. In the Electricity
Building alone 15,000 incandescent lamps are used for light-
ing. The total for the entire exposition is 92,622 lamps. A
model electric kitchen is shown with a display of electrical
appliances, including an electrically heated saucepan, chafing
dish, coffeepot, and grill.
1893 In June publication of "Electrical Engineering," a semi-
monthly magazine, is begun in Chicago.
1893 PROFESSOR LIONEL SIMEON MARKS ( ) of
Harvard University publishes the results of the studies of
enclosed arc lights and the effects on arc lights of varying
the current and voltage. He develops a high-voltage lamp with
enclosed carbons which, he says, will burn for a hundred and
1893 LOUIS B. MARKS (1869-1939), an illuminating engineer of
New York, designs an enclosed arc lamp and sells his patent
rights to General Electric.
1893 Incandescent lamps containing cellulose filament are intro-
duced (3.3 lumens per watt) .
1893 The first Wood electric automobile, built by the Chicago Elec-
tric and Manufacturing Co. is tested on a Chicago street and
creates "some excitement all along the route."
1893 Elisha Gray (see 1869) is granted February 7 a patent for
1893 Philip Diehl (see 1878) invents the first combined electric fan
and electrolier (lighting fixture) . The patent was issued June
1894 Elihu Thomson (see 1875) patents the first resistance furnace.
1894 SIR OLIVER LODGE (1851-1940) publishes an article in the
"The Electrician" (London) in which he discusses the dis-
coveries of Hertz, describes his own experiments with elec-
tromagnetic waves, and observes that "some circuits are per-
sistent vibrators 'that is, they are able to sustain for long
periods oscillations set up in them," while other "circuits are
so constructed that their oscillations are rapidly damped."
1894 What is claimed to be the first compensating winding and
commutating pole generator is rated at 10 kilowatts, 91
amperes, 110 volts, and 1,200 rpm. This is the Thomson-
Ryan Dynamo "901" with copper brushes and interpole face
windings. This machine is (in 1945) in the Edison Institute,
Greenfield Village, Dearborn, Michigan.
1894 A contract is let for twenty-six miles of 11,000 volt, 3 phase
electric power transmission, one of the longest to this date,
from Niagara Falls to Buffalo, New York. This line was not
placed in service until November, 1896.
1894 The first motion pictures are shown April 14 in a former shoe
store at 1155 Broadway, New York. Ten of Edison's first kine-
toscopes (see 1891) are used.
1894 Pupin (see 1889) publishes his researches on "electric tuning"
and obtains patents which were later licensed to the Marconi
Co. in 1903.
1895 PROFESSOR WILHELM KONRAD ROENTGEN (1845-
1923) discovers rays which "emanate from the bombardment
of a metallic plate by electrons in an evacuated tube." It is
not understood what these rays are, so they are called X rays.
Roentgen was awarded the Nobel prize for physics in 1901.
1895 ARTURO MALIGNANI ( ) , Italian engineer, evolves
the use of red phosphorous vapor in producing the vacuum in
an incandescent lamp, an important contribution. General
Electric purchases the United States rights to the invention.
1895 A 5.95-mile section of the New Haven Railroad's Nantasket
Beach branch in Massachusetts is electrified. Service is sup-
plied to motor-trailer trains from an overhead trolley system.
This is the first example of standard railroad electrification
in this country.
1895 GUGLIELMO MARCONI (1874-1937), Italian electrician,
inventor of wireless telegraphy, starts his experiments in his
home in Bologna, transmits signals one mile without wires.
1895 The constant-potential arc lamp, for 110 volt constant, mul-
tiple circuits, is developed by Elihu Thomson (see 1875) .
1895 The "Journal of Electricity" a monthly magazine is published
in July in San Francisco.
1895 Westinghouse Electric & Manufacturing Company installs the
first high-capacity hydroelectric system at Niagara Falls.
This consists of three 5,000 horsepower, 2 phase, 2,200 volt,
25 cycle, 250 rpm alternators having an external revolving
field. This plant continued in commercial service until about
1924. It was however, maintained as a standby plant until
the summer of 1941 when it was again placed in service as a
wartime measure. The first three machines installed in 1895
were rebuilt in 1921 to operate at 12,000 volt, 3 phase.
1895 PIERRE CURIE (1859-1906), French physicist, discovers
what is later called the "Curie Point" and relates to variations
of magnetic properties. His discovery was modified by later
experimental results. The American Standards Association
defines the "Curie Point" as follows: "The magnetic transi-
tion temperature of a ferromagnetic material is the tempera-
ture at which, with increasing temperature, the transition
from ferromagnetic to paramagnetic appears to be complete.
The change in magnetic properties with temperature extends
over an appreciable temperature interval, so that the value
obtained for the magnetic transition temperature depends
upon experimental conditions" (05.40.095) .
1896 Marconi (see 1895) applies for his original and basic (British)
patent for wireless telegraphy June 2 (Patent No. 12,039).
Equivalent American patent, No. 586,193, was granted July
1896 DR. NIELS RYDBERG FINSEN ( ) discovers that
violet rays are an enemy of disease, and inaugurates electric
1896 The Hartford Electric Light Company installs at Hartford,
Connecticut, the first electric hydraulic plant to use a storage
battery to meet peak load requirements.
1896 The first commercial projection on a motion picture screen
takes place April 23. The films for the performance were made
in the first motion picture studio at Edison's West Orange,
New Jersey, plant.
1896 ANTOINE HENRI BECQUEREL (1852-1908) , French physi-
cist, experiments with minerals containing uranium. His re-
search opens the way to radioactivity and Curie's discovery
1896 The General Electric Company and the Westinghouse Electric
& Manufacturing Company license each other to manufacture
under its patents. General Electric holds the patents of Thom-
son, Brush, Edison, Sprague, Van Depoele, Bradley, and
others; Westinghouse holds those of Sawyer-Man, Maxim,
Weston, Tesla, Stanley, and others.
1896 "The Telephone," a monthly magazine, begins publication in
March in Chicago.
1896 EDWARD GOODRICH ACHESON (1856-1931), American
inventor, receives Patent No. 560,291 for an "Electric Fur-
1896 The commercial steam turbine (based on exclusive Parson's
license) is introduced into America by Westinghouse about
1895. A 120 kilowatt direct-current set is built at Pittsburgh
1896 In May the "American Electrician" is published. This maga-
zine was originally called the "Electric Industries" and was
established in 1889.
1896 De Laval (see 1882) designs, and the French De Laval Co.
builds, the first steam turbines used in American central
stations. There are two 300 horsepower, single-stage geared
turbine generators installed in two plants of the New York
1896 The Ward Leonard Electric Co. manufactures the first elec-
trically heated flatirons with several replaceable heater units.
1896 Charles G. Curtis (see 1885) starts work on the development
of his turbine at the Schenectady Works of General Electric
1896 Pupin (see 1889) discovers secondary X-ray radiation and
"originates the use of the intensifying screen in making X-ray
1896 Edison files a patent on the first fluorescent lamp May 19.
1897 NICHOLAS SLAWIANOFF receives United States Patent
No. 577, 329 on metallic arc welding February 16.
1897 The first electric automobiles make their appearance. At the
New York Auto Show in 1900, electrics far outnumber the
steam and gasoline cars.
1897 Westinghouse (see 1886) builds the first polyphase induction
regulator for varying the voltage of a synchronous converter.
1897 SIR JOSEPH JOHN THOMSON (1856-1940), English physi-
cist, advances his electronic theory.
1897 SIR WILLIAM HENRY PREECE (1834-1913), Marconi's
collaborator in England, engineer-in-chief of the British Post
Office, publishes a paper, "Signaling Through Space Without
Wires," in which he describes Marconi's experiments in Great
Britain, mostly by means of Hertzian waves concentrated
into a single beam by parabolic reflectors. Marconi transmits
signals in the Morse code across the Bristol channel, a distance
of nine miles.
1897 Guglielmo Marconi (see 1895) receives Patent No. 586,193
for "New and Useful Improvements in Transmitting Elec-
trical Impulses and Signals and in the Apparatus Thereof . . .
by means of oscillations of high frequency." This is commonly
called wireless telegraphy.
1897 DR. RUDOLPH DIESEL (1858-1913), German engineer, in-
vents the engine that bears his name. The original Diesel
engine weighed four hundred and fifty pounds to the horse-
power. August 9, 1898, he received Patent No. 608,845 for
"New and Useful Improvements in Internal Combustion En-
gines." The Diesel engine has become an important factor in
the generation of cheap electric power in comparatively small
quantities. The largest engine to date (1945) is rated at 8,000
1897 PROFESSOR WALTHER NERNST (1864-1941) of Berlin
devises an incandescent lamp that requires no vacuum and
consumes only half the power of the ordinary carbon filament
for the same amount of light. The Nernst filament consists of
a short rod of magnesium oxide, a poor conductor of electricity
when cold, but a good conductor when heated. To start the
light the filament is heated with an electrically heated plati-
1897 ROBERT H. MACHLETT, founder of Machlett Laboratories,
Inc., produces one of the first operable X-ray tubes in America.
1898 Westinghouse (see 1886) builds a 100,000 volt test set for
testing insulating material and insulators in the field.
1898 Marconi, abandoning the single beam method of transmitting
telegraphic signals without wires sends signals via aerials,
the signals going out in all directions. With this system,
Marconi transmits signals between Bournemouth and Alum
Bay, Isle of Wight, about fourteen miles.
1898 The first patented flashlights are produced and announced.
Among the important contributors are the names of Bugg,
Paget, Misell, and Hubert. Early patents were assigned to the
American Electrical Novelty & Mfg. Co., predecessor of the
American Ever Ready Co. which later became part of the Na-
tional Carbon Co., Inc. The early flashlights were in the nature
of toys and novelties.
1898 HUGO BREMER ( ) of Germany and ANDREW
BLONDEL ( ) of France independently discover that
by incorporating metallic salts in the structure of lighting
carbons it is possible to obtain a luminous or flaming arc of
considerable intensity. The metallic salts volatilize in the arc
stream thereby making it the principal source of energy emis-
sion instead of the incandescent tips of the carbons as was the
case with the pure carbon arc. Following this discovery many
types of flaming arc lamps were introduced abroad and in this
1898 The first use of electricity in war as a motive power for all
turrets, ammunition hoists, and auxiliary machines, a Ward
Leonard system of control, is July 3 on the U. S. cruiser
"Brooklyn," during the Battle of Santfago. Of the lessons of
the Spanish-American War with respect to employment of
electricity aboard men-of-war the most decisive result was
the demonstration of the immense superiority of electricity
over steam for the operation of turret training apparatus.
1898 Sir Oliver Lodge (see 1894) receives Patent No. 609,154
August 16 for "tuning." His system included an induction
coil in the antenna circuit of a wireless transmitter or receiver,
or both, making it possible to put the transmitter and receiver
in tune with each other.
1898 The constant-current transformer, permitting arc lamps to be
linked into alternating-current supply systems and supplied
with fixed or constant current is invented by Elihu Thomson
1899 WALTER D'A. RYAN begins his systematic study of light-
ing, opens a modest illuminating engineering laboratory at
Lynn, Massachusetts, and conducts an educational campaign
on the scientific planning of lighting installations.
1899 In April Marconi transmits a wireless telegraph message from
Folkestone to Boulogne, a distance of thirty-two miles the
first international wireless transmission.
1899 Michael Idvorsky Pupin (see 1889) invents the telephone
"repeater," or "Pupin" coils. The patent for this was acquired
by the American Telephone and Telegraph Co. in 1901.
1899 The first comprehensive installation of steam turbine-driven
generators is made with three Westinghouse 400 kilowatt,
alternating-current turbine generator sets installed at Wilmer-
1899 In June the A.I.E.E. makes its first report on standardization.
Recommended for trial by both manufacturers and users of
electrical equipment, it is the ground work of all future elec-
1899 Armored cable is first recognized as a wiring method in the
National Electrical Code.
1899 The "lining" in conduit for wiring purposes is removed by the
National Electrical Code. "Lined" conduit continued to have
recognition for some years and was specified for conduit wir-
ing in elevator shafts until 1928.
1900 The Manhattan Elevated Railway is electrified. The first in-
stallation includes 1,700 motors and the largest generators
physical size) ever built, operating at 75 rpm and delivering
current at 25 cycles. This current was changed to direct cur-
rent by means of synchronous converters located in different
substations throughout the city.
1900 Ground is broken for the first subway in New York.
1900 The General Electric Research Laboratory is established at
Schenectady, New York.
1900 Charles G. Curtis (see 1885) and WILLIAM LEROY EMMET
(1859-1941) design their first turbines in the General Electric
Laboratories in Schenectady.
1900 The American Telephone & Telegraph Co. becomes the parent
company of the Bell System.
1900 S. H. STUPAKOFF, SR. ( ) manufactures and intro-
duces the first pyrometers to industry in the United States.
1900 Edwards and Co. introduces the "Carriage Call," used by
Tiffany and Company, New York, and others.
1900 The Fifth International Electrical Congress is held at Paris,
France, in August. At this Congress the unit "gauss" is deter-
mined for the C.G.S. unit of field intensity and the "max-
well" for the C.G.S. unit of magnetic flux.
1900 The first escalator, built by Otis Elevator Co. of New York City,
is exhibited at the Paris Exposition, Paris, France. After the
Paris Exhibition it was returned to the United States and in
1901 installed in Philadelphia in the Eighth Street building of
Gimbel Brothers department store.
1900 Charles P. Steinmetz (see 1889) develops a new light source
for arc lamps, an electrode made up partly of magnetite and
partly of titanium, giving an illumination so brilliant that it
is commercially named the luminous arc.
1901 The Hartford Electric Light Co., Hartford, Connecticut, places
in operation a Westinghouse steam turbine rated at 1,500
kilowatts, 2,400 volts, 2 phase, 60 cycles, 1,200 rpm the
largest constructed to date.
1901 PETER COOPER HEWITT (1861-1921) invents at Newark,
New Jersey, a mercury-vapor arc lamp.
1901 The National Electrical Contractors Association is organized
July 17, with forty-eight delegates representing the contrac-
tors in seven states. Membership in 1945 was about 1,300,
including members in Canada, Mexico, South America, and
1901 The National Bureau of Standards is established in March
with a staff of about fourteen. The present (1945) electrical
division has a staff of about one hundred and sixty members.
1901 Radio rescues its first ship: The Royal Belgian steamer
"Princess Clementine," one of the first ships equipped with
Marconi's wireless apparatus, finds the barque "Medora" of
Stockholm grounded on the Ratel Bank. The Belgian skipper
immediately sends a wireless message to La Panne on the
Belgian Coast, and within an hour a rescue vessel is on its
way to aid the "Medora."
1901 The single-phase commutator type motor with variable speeds
is developed for traction service.
1901 General Electric Company retains DR. WILLIS R. WHITNEY
(1868- ) of Massachusetts Institute of Technology to head
its new research laboratory (see 1900) . The first work, with
Steinmetz (see 1892) , is done in an old barn at Schenectady.
1901 Marconi sends the first radio signal October 12 the letter "S"
across the Atlantic Ocean from Poldhu, Cornwall, to St.
1901 "Electrical Contracting," the magazine of electrical construc-
tion and maintenance, is established.
1902 The first conversation by long distance underground cable is
held between New York City and Newark, New Jersey.
1902 The American Electrochemical Society is founded in April.
Later the word "American" is dropped from the title. The
Society is divided into seven important divisions : electrother-
mic, electrodeposition, electronics, electro-organic, corrosion,
industrial electrolytic, and theoretical electrochemistry. The
Society was incorporated in 1930 and in 1945 has a member-
ship of almost 1,700.
1902 Peter Cooper Hewitt (see 1900) invents the mercury arc recti-
fier used for converting alternating current into direct cur-
1902 Two of the largest engine-type generators built for Cincin-
nati Gas & Electric Co. are placed in operation. The alternator
is rated at 3,200 kva, 3 phase, 60 cycle, 2,400 volt alternators
operating at 75 rpm, and has a rotor diameter of 30 feet.
The direct-current, 250 volt generator of the same rating and
speed has an armature 20 feet in diameter.
1902 REGINALD AUBREY FESSENDEN (1866-1932) , American
pioneer in wireless, invents the electrolytic or chemical de-
tector which increases the range and effectiveness of wireless.
1902 JOHN STONE STONE (1869-1943) receives Patent No. 714,-
756 on tuning-in connection with wireless telegraph apparatus.
1902 The first cable across the Pacific between San Francisco and
Honolulu (2,600 miles) is played out by the cable ship "Silver-
ton", leaving San Francisco December 14, 1902, and arriving
at Honolulu January 1, 1903. The first message was sent that
day ; the cable was open for public use four days later.
1903 The first commercial installation of the luminous arc lamp
(see 1900) is made at Jackson, Michigan.
1903 The first experimental trolley coach line, whereby vehicles run
on the street and collect current from a two-wire overhead