Joseph Henry (December 17, 1797– May 13, 1878) was an American scientist who served as the first Secretary of the
Smithsonian Institution
The Smithsonian Institution ( ), or simply the Smithsonian, is a group of museums and education and research centers, the largest such complex in the world, created by the U.S. government "for the increase and diffusion of knowledge". Founded ...
. He was the secretary for the
National Institute for the Promotion of Science
The National Institution for the Promotion of Science organization was established in Washington, D.C. in May 1840, and was heir to the mantle of the earlier ''Columbian Institute for the Promotion of Arts and Sciences''. The National Institution ...
, a precursor of the Smithsonian Institution.
While building electromagnets, Henry discovered the
electromagnetic
In physics, electromagnetism is an interaction that occurs between particles with electric charge. It is the second-strongest of the four fundamental interactions, after the strong force, and it is the dominant force in the interactions o ...
phenomenon of self-
inductance. He also discovered mutual inductance independently of
Michael Faraday
Michael Faraday (; 22 September 1791 – 25 August 1867) was an English scientist who contributed to the study of electromagnetism and electrochemistry. His main discoveries include the principles underlying electromagnetic inducti ...
, though Faraday was the first to make the discovery and publish his results. Henry developed the
electromagnet
An electromagnet is a type of magnet in which the magnetic field is produced by an electric current. Electromagnets usually consist of wire wound into a coil. A current through the wire creates a magnetic field which is concentrated in ...
into a practical device. He invented a precursor to the electric
doorbell
A doorbell is a signaling device typically placed near a door to a building's entrance. When a visitor presses a button, the bell rings inside the building, alerting the occupant to the presence of the visitor. Although the first doorbells were ...
(specifically a bell that could be rung at a distance via an electric wire, 1831) and electric
relay
A relay
Electromechanical relay schematic showing a control coil, four pairs of normally open and one pair of normally closed contacts
An automotive-style miniature relay with the dust cover taken off
A relay is an electrically operated switch ...
(1835). His work on the electromagnetic relay was the basis of the practical
electrical telegraph
Electrical telegraphs were point-to-point text messaging systems, primarily used from the 1840s until the late 20th century. It was the first electrical telecommunications system and the most widely used of a number of early messaging systems ...
, invented separately by
Samuel F. B. Morse
Samuel Finley Breese Morse (April 27, 1791 – April 2, 1872) was an American inventor and painter. After having established his reputation as a portrait painter, in his middle age Morse contributed to the invention of a single-wire telegraph ...
and
Sir Charles Wheatstone
Sir Charles Wheatstone FRS FRSE DCL LLD (6 February 1802 – 19 October 1875), was an English scientist and inventor of many scientific breakthroughs of the Victorian era, including the English concertina, the stereoscope (a device for dis ...
. In his honor, the
SI unit of
inductance is named the
henry
Henry may refer to:
People
*Henry (given name)
* Henry (surname)
* Henry Lau, Canadian singer and musician who performs under the mononym Henry
Royalty
* Portuguese royalty
** King-Cardinal Henry, King of Portugal
** Henry, Count of Portugal, ...
(plural: henries; symbol: H
[
]).
Early life and education
Henry was born in
Albany, New York
Albany ( ) is the capital of the U.S. state of New York, also the seat and largest city of Albany County. Albany is on the west bank of the Hudson River, about south of its confluence with the Mohawk River, and about north of New York C ...
, to
Scottish immigrants Ann Alexander Henry and William Henry. His parents were poor, and Henry's father died while he was still young. For the rest of his childhood, Henry lived with his grandmother in
Galway, New York
Galway () is a town located in Saratoga County, New York, United States. As of the 2000 census, the town had a total population of 3,589. The town contains a village also named Galway. Both the town and village are located in the western part o ...
. After school, he worked at a general store, and at the age of thirteen became an apprentice
watchmaker
A watchmaker is an artisan who makes and repairs watches. Since a majority of watches are now factory-made, most modern watchmakers only repair watches. However, originally they were master craftsmen who built watches, including all their part ...
and
silversmith
A silversmith is a metalworker who crafts objects from silver. The terms ''silversmith'' and ''goldsmith'' are not exactly synonyms as the techniques, training, history, and guilds are or were largely the same but the end product may vary grea ...
. Joseph's first love was theater, and he came close to becoming a professional actor. His interest in science was sparked at the age of sixteen by a book of lectures on scientific topics titled ''Popular Lectures on Experimental Philosophy''.
In 1819, he entered
The Albany Academy
The Albany Academy is an independent college preparatory day school for boys in Albany, New York, USA, enrolling students from Preschool (age 3) to Grade 12. It was established in 1813 by a charter signed by Mayor Philip Schuyler Van Renssela ...
, where he was given free tuition. Even with free tuition, he was so poor that he had to support himself with teaching and private tutoring positions. He intended to go into medicine, but in 1824 he was appointed an assistant engineer for the
survey
Survey may refer to:
Statistics and human research
* Statistical survey, a method for collecting quantitative information about items in a population
* Survey (human research), including opinion polls
Spatial measurement
* Surveying, the techniq ...
of the State road being constructed between the
Hudson River
The Hudson River is a river that flows from north to south primarily through eastern New York. It originates in the Adirondack Mountains of Upstate New York and flows southward through the Hudson Valley to the New York Harbor between N ...
and
Lake Erie
Lake Erie ( "eerie") is the fourth largest lake by surface area of the five Great Lakes in North America and the eleventh-largest globally. It is the southernmost, shallowest, and smallest by volume of the Great Lakes and therefore also h ...
. From then on, he was inspired to a career in either
civil
Civil may refer to:
*Civic virtue, or civility
*Civil action, or lawsuit
* Civil affairs
*Civil and political rights
*Civil disobedience
*Civil engineering
*Civil (journalism), a platform for independent journalism
*Civilian, someone not a membe ...
or
mechanical engineering
Mechanical engineering is the study of physical machines that may involve force and movement. It is an engineering branch that combines engineering physics and mathematics principles with materials science, to design, analyze, manufacture, an ...
. Henry excelled academically, even often helping his teachers teach science.
Career
In 1826, he was appointed Professor of Mathematics and Natural Philosophy at
The Albany Academy
The Albany Academy is an independent college preparatory day school for boys in Albany, New York, USA, enrolling students from Preschool (age 3) to Grade 12. It was established in 1813 by a charter signed by Mayor Philip Schuyler Van Renssela ...
by Principal
T. Romeyn Beck. Some of his most important research was conducted in this new position. His curiosity about
terrestrial magnetism
Earth's magnetic field, also known as the geomagnetic field, is the magnetic field that extends from Earth's interior out into space, where it interacts with the solar wind, a stream of charged particles emanating from the Sun. The magnetic fi ...
led him to experiment with
magnetism in general. He was the first to coil insulated wire tightly around an iron core in order to make a more powerful electromagnet, improving on
William Sturgeon
William Sturgeon (22 May 1783 – 4 December 1850) was an English physicist and inventor who made the first electromagnets, and invented the first practical British electric motor.
Early life
Sturgeon was born on 22 May 1783 in Whittington, ...
's electromagnet which used loosely coiled uninsulated wire. Using this technique, he built the strongest electromagnet at the time, for
Yale
Yale University is a private research university in New Haven, Connecticut. Established in 1701 as the Collegiate School, it is the third-oldest institution of higher education in the United States and among the most prestigious in the wor ...
. He also showed that, when making an electromagnet using just two
electrode
An electrode is an electrical conductor used to make contact with a nonmetallic part of a circuit (e.g. a semiconductor, an electrolyte, a vacuum or air). Electrodes are essential parts of batteries that can consist of a variety of materials d ...
s attached to a battery, it is best to wind several coils of wire in parallel, but when using a set-up with multiple batteries, there should be only one single long coil. The latter made the
telegraph
Telegraphy is the long-distance transmission of messages where the sender uses symbolic codes, known to the recipient, rather than a physical exchange of an object bearing the message. Thus flag semaphore is a method of telegraphy, whereas p ...
feasible. Because of his early experiments in electromagnetism, some historians credit Henry with discoveries pre-dating Faraday and Hertz; however, Henry is not credited due to not publishing his work.
Using his newly developed electromagnetic principle, in 1831, Henry created one of the first machines to use electromagnetism for motion. This was the earliest ancestor of modern
DC motor. It did not make use of rotating motion, but was merely an electromagnet perched on a pole, rocking back and forth. The rocking motion was caused by one of the two leads on both ends of the magnet rocker touching one of the two battery cells, causing a polarity change, and rocking the opposite direction until the other two leads hit the other battery.
This apparatus allowed Henry to recognize the property of
self inductance. British scientist
Michael Faraday
Michael Faraday (; 22 September 1791 – 25 August 1867) was an English scientist who contributed to the study of electromagnetism and electrochemistry. His main discoveries include the principles underlying electromagnetic inducti ...
also recognized this property around the same time. Since Faraday published his results first, he became the officially recognized discoverer of the phenomenon.
Princeton
From 1832 to 1846, Henry served as the first Chair of Natural History at the College of New Jersey, which is now
Princeton University
Princeton University is a private research university in Princeton, New Jersey. Founded in 1746 in Elizabeth as the College of New Jersey, Princeton is the fourth-oldest institution of higher education in the United States and one of the ...
.
While in Princeton, he taught a wide range of courses including
natural history, chemistry, and architecture, and ran a laboratory on campus. Decades later, Henry wrote that he made "several thousand original investigations on electricity, magnetism, and electro-magnetism" while on the Princeton faculty. Henry relied heavily on an African American research assistant, Sam Parker, in his laboratory and experiments. Parker was a free black man hired by the Princeton trustees to assist Henry. In an 1841 letter to mathematician
Elias Loomis
Elias Loomis (August 7, 1811 – August 15, 1889) was an American mathematician. He served as a professor of mathematics and natural philosophy at Western Reserve College (now Case Western Reserve University), the University of the City of New Yo ...
, Henry wrote:
The Trustees have however furnished me with an article which I now find indispensable namely with a coloured servant whom I have taught to manage my batteries and who now relieves me from all the dirty work of the laboratory.
In his letters, Henry described Parker providing materials for experiments, fixing technical issues with Henry's equipment, and at times being used as a test subject in electrical experiments in which Henry and his students would shock Parker in classroom demonstrations.
In 1842, when Parker fell ill, Henry's experiments stopped completely until he recovered.
Smithsonian
Henry was appointed the first Secretary of the
Smithsonian Institution
The Smithsonian Institution ( ), or simply the Smithsonian, is a group of museums and education and research centers, the largest such complex in the world, created by the U.S. government "for the increase and diffusion of knowledge". Founded ...
in 1846, and served in this capacity until 1878. In 1848, while Secretary, Henry worked in conjunction with
Professor Stephen Alexander to determine the relative temperatures for different parts of the solar disk. They used a
thermopile
A thermopile is an electronic device that converts thermal energy into electrical energy. It is composed of several thermocouples connected usually in series or, less commonly, in parallel. Such a device works on the principle of the thermoele ...
to determine that
sunspots were cooler than the surrounding regions. This work was shown to the astronomer
Angelo Secchi
Angelo Secchi (; 28 June 1818 – 26 February 1878) was an Italian Catholic priest, astronomer from the Italian region of Emilia. He was director of the observatory at the Pontifical Gregorian University (then called the Roman College) for ...
who extended it, but with some question as to whether Henry was given proper credit for his earlier work.
In late 1861 and early 1862, during the
American Civil War
The American Civil War (April 12, 1861 – May 26, 1865; also known by other names) was a civil war in the United States. It was fought between the Union ("the North") and the Confederacy ("the South"), the latter formed by states ...
, Henry oversaw a series of lectures by prominent
abolitionists
Abolitionism, or the abolitionist movement, is the movement to end slavery. In Western Europe and the Americas, abolitionism was a historic movement that sought to end the Atlantic slave trade and liberate the enslaved people.
The Britis ...
at the Smithsonian Institution.
Speakers included white clergymen, politicians, and activists such as
Wendell Phillips
Wendell Phillips (November 29, 1811 – February 2, 1884) was an American abolitionist, advocate for Native Americans, orator, and attorney.
According to George Lewis Ruffin, a Black attorney, Phillips was seen by many Blacks as "the one whi ...
,
Horace Greeley,
Henry Ward Beecher
Henry Ward Beecher (June 24, 1813 – March 8, 1887) was an American Congregationalist clergyman, social reformer, and speaker, known for his support of the abolition of slavery, his emphasis on God's love, and his 1875 adultery trial. His r ...
, and
Ralph Waldo Emerson
Ralph Waldo Emerson (May 25, 1803April 27, 1882), who went by his middle name Waldo, was an American essayist, lecturer, philosopher, abolitionist, and poet who led the transcendentalist movement of the mid-19th century. He was seen as a champ ...
. Famous orator and former fugitive slave
Frederick Douglass
Frederick Douglass (born Frederick Augustus Washington Bailey, February 1817 or 1818 – February 20, 1895) was an American social reformer, abolitionist, orator, writer, and statesman. After escaping from slavery in Maryland, he became ...
was scheduled as the final speaker; Henry, however, refused to allow him to attend, stating: "I would not let the lecture of the coloured man be given in the rooms of the Smithsonian."
In the fall of 2014, history author Jeremy T.K. Farley released ''The Civil War Out My Window: Diary of Mary Henry''. The 262-page book featured the detailed diary of Henry's daughter
Mary Anna Henry, kept from the years of 1855 to 1878 while living in the
Smithsonian Castle. Throughout the diary, Henry is repeatedly mentioned by his daughter, who showed a keen affection to her father.
Influences in aeronautics
Henry was introduced to
Prof. Thaddeus Lowe, a balloonist from New Hampshire who had taken interest in the phenomenon of lighter-than-air gases, and exploits into meteorology, in particular, the high winds which we call the
Jet stream today. It was Lowe's intent to make a transatlantic crossing by utilizing an enormous gas-inflated aerostat. Henry took a great interest in Lowe's endeavors, promoting him among some of the more prominent scientists and institutions of the day.
In June 1860, Lowe had made a successful test flight with his gigantic balloon, first named the ''City of New York'' and later renamed ''The Great Western'', flying from
Philadelphia
Philadelphia, often called Philly, is the List of municipalities in Pennsylvania#Municipalities, largest city in the Commonwealth (U.S. state), Commonwealth of Pennsylvania, the List of United States cities by population, sixth-largest city i ...
to
Medford, New York
Medford is a hamlet and census-designated place (CDP) in the Town of Brookhaven in Suffolk County, on Long Island, in New York, United States. The population was 24,142 at the 2010 census.
History
The Long Island Rail Road established the M ...
. Lowe would not be able to attempt a transatlantic flight until late Spring of the 1861, so Henry convinced him to take his balloon to a point more West and fly the balloon back to the eastern seaboard, an exercise that would keep his investors interested.
Lowe took several smaller balloons to
Cincinnati, Ohio
Cincinnati ( ) is a city in the U.S. state of Ohio and the county seat of Hamilton County. Settled in 1788, the city is located at the northern side of the confluence of the Licking and Ohio rivers, the latter of which marks the state line wi ...
in March 1861. On 19 April, he launched on a fateful flight that landed him in
Confederate South Carolina. With the Southern States seceding from the Union, during that winter and spring of 1861, and the onset of Civil War, Lowe abandoned further attempts at a trans-Atlantic crossing and, with Henry's endorsement, went to Washington, D.C. to offer his services as an aeronaut to the Federal government. Henry submitted a letter to
U.S. Secretary of War
The secretary of war was a member of the U.S. president's Cabinet, beginning with George Washington's administration. A similar position, called either "Secretary at War" or "Secretary of War", had been appointed to serve the Congress of th ...
at the time
Simon Cameron
Simon Cameron (March 8, 1799June 26, 1889) was an American businessman and politician who represented Pennsylvania in the United States Senate and served as United States Secretary of War under President Abraham Lincoln at the start of the Americ ...
of Pennsylvania which carried Henry's endorsement:
On Henry's recommendation Lowe went on to form the
United States Army/"Union Army" Balloon Corps and served two years with the
Army of the Potomac
The Army of the Potomac was the principal Union Army in the Eastern Theater of the American Civil War. It was created in July 1861 shortly after the First Battle of Bull Run and was disbanded in June 1865 following the surrender of the Confede ...
as a Civil War "Aeronaut".
Later years
As a famous scientist and director of the Smithsonian Institution, Henry received visits from other scientists and inventors who sought his advice. Henry was patient, kindly, self-controlled, and gently humorous. One such visitor was
Alexander Graham Bell, who on 1 March 1875 carried a letter of introduction to Henry. Henry showed an interest in seeing Bell's experimental apparatus, and Bell returned the following day. After the demonstration, Bell mentioned his untested theory on how to transmit human speech electrically by means of a "harp apparatus" which would have several steel reeds tuned to different frequencies to cover the voice spectrum. Henry said Bell had "the germ of a great invention". Henry advised Bell not to publish his ideas until he had perfected the invention. When Bell objected that he lacked the necessary knowledge, Henry firmly advised: "Get it!"
On June 25, 1876, Bell's experimental telephone, using a different design, was demonstrated at the Centennial Exhibition in
Philadelphia
Philadelphia, often called Philly, is the List of municipalities in Pennsylvania#Municipalities, largest city in the Commonwealth (U.S. state), Commonwealth of Pennsylvania, the List of United States cities by population, sixth-largest city i ...
, where Henry was one of the judges for electrical exhibits. On 13 January 1877, Bell demonstrated his instruments to Henry at the Smithsonian Institution and Henry invited Bell to demonstrate them again that night at the
Washington Philosophical Society. Henry praised "the value and astonishing character of Mr. Bell's discovery and invention."
Henry died on May 13, 1878, and was buried in
Oak Hill Cemetery in the
Georgetown section of northwest Washington, D.C.
John Phillips Sousa wrote the
Transit of Venus March for the unveiling of the Joseph Henry statue in front of the
Smithsonian Castle.
Legacy
Henry was a member of the
United States Lighthouse Board
The United States Lighthouse Board was the second agency of the U.S. federal government, under the Department of Treasury, responsible for the construction and maintenance of all lighthouses and navigation aids in the United States, between 18 ...
from 1852 until his death. He was appointed chairman in 1871 and served in that position the remainder of his life. He was the only civilian to serve as chairman. The
United States Coast Guard
The United States Coast Guard (USCG) is the maritime security, search and rescue, and law enforcement service branch of the United States Armed Forces and one of the country's eight uniformed services. The service is a maritime, military, mu ...
honored Henry for his work on lighthouses and fog signal acoustics by naming a cutter after him. The ''
Joseph Henry'', usually referred to as the ''Joe Henry'', was launched in 1880 and was active until 1904.
[US Coast Guard Cutter Joseph Henry](_blank)
/ref>
In 1915, Henry was inducted into the Hall of Fame for Great Americans
The Hall of Fame for Great Americans is an outdoor sculpture gallery located on the grounds of Bronx Community College (BCC) in the Bronx, New York City. It is the first such hall of fame in the United States. Built in 1901 as part of the U ...
in the Bronx, New York.
Bronze statues of Henry and Isaac Newton
Sir Isaac Newton (25 December 1642 – 20 March 1726/27) was an English mathematician, physicist, astronomer, alchemist, theologian, and author (described in his time as a " natural philosopher"), widely recognised as one of the grea ...
represent science on the balustrade of the galleries of the Main Reading Room in the Thomas Jefferson Building
The Thomas Jefferson Building is the oldest of the four United States Library of Congress buildings. Built between 1890 and 1897, it was originally known as the Library of Congress Building. It is now named for the 3rd U.S. president Thomas Jeffe ...
of the Library of Congress
The Library of Congress (LOC) is the research library that officially serves the United States Congress and is the ''de facto'' national library of the United States. It is the oldest federal cultural institution in the country. The library ...
on Capitol Hill in Washington, D.C.
)
, image_skyline =
, image_caption = Clockwise from top left: the Washington Monument and Lincoln Memorial on the National Mall, United States Capitol, Logan Circle, Jefferson Memorial, White House, Adams Morgan, ...
They are two of the 16 historical figures depicted in the reading room, each pair representing one of the 8 pillars of civilization.
In 1872, John Wesley Powell
John Wesley Powell (March 24, 1834 – September 23, 1902) was an American geologist, U.S. Army soldier, explorer of the American West, professor at Illinois Wesleyan University, and director of major scientific and cultural institutions. He ...
named a mountain range in southeastern Utah after Henry. The Henry Mountains
The Henry Mountains is a mountain range located in the southeastern portion of the U.S. state of Utah that runs in a generally north-south direction, extending over a distance of about . They were named by Almon Thompson in honor of Joseph Henry ...
were the last mountain range to be added to the map of the 48 contiguous U.S. states.
At Princeton University
Princeton University is a private research university in Princeton, New Jersey. Founded in 1746 in Elizabeth as the College of New Jersey, Princeton is the fourth-oldest institution of higher education in the United States and one of the ...
, the Joseph Henry Laboratories and the Joseph Henry House
The Joseph Henry House is a historic building located on the campus of Princeton University in Princeton, Mercer County, New Jersey, United States. Joseph Henry, a prominent American physicist who worked in electromagnetics, designed the house in ...
are named for him.
After the Albany Academy
The Albany Academy is an independent college preparatory day school for boys in Albany, New York, USA, enrolling students from Preschool (age 3) to Grade 12. It was established in 1813 by a charter signed by Mayor Philip Schuyler Van Rensselaer ...
moved out of its downtown building in the early 1930s, its old building in Academy Park was renamed Joseph Henry Memorial with a statue of him in front. It is now the main offices of the Albany City School District
The City School District of Albany (also known as the Albany City School District) is the public school district of Albany, New York, Albany, New York (state), New York. The district is an independent public entity. It is governed by the City Sc ...
. In 1971, it was listed on the National Register of Historic Places
The National Register of Historic Places (NRHP) is the United States federal government's official list of districts, sites, buildings, structures and objects deemed worthy of preservation for their historical significance or "great artistic ...
; later it was included as a contributing property when the Lafayette Park Historic District was listed on the Register.
Curriculum vitae
*1826 – Professor of mathematics and natural philosophy at The Albany Academy
The Albany Academy is an independent college preparatory day school for boys in Albany, New York, USA, enrolling students from Preschool (age 3) to Grade 12. It was established in 1813 by a charter signed by Mayor Philip Schuyler Van Renssela ...
, New York.
*1832 – Chair of Natural History at Princeton University (then the College of New Jersey) until 1846
*1835 – Invented the electromechanical relay
A relay
Electromechanical relay schematic showing a control coil, four pairs of normally open and one pair of normally closed contacts
An automotive-style miniature relay with the dust cover taken off
A relay is an electrically operated switch ...
.
*1846 – First secretary of the Smithsonian Institution
The Smithsonian Institution ( ), or simply the Smithsonian, is a group of museums and education and research centers, the largest such complex in the world, created by the U.S. government "for the increase and diffusion of knowledge". Founded ...
[ until 1878
*1848 – Edited Ephraim G. Squier and Edwin H. Davis' '']Ancient Monuments of the Mississippi Valley
''Ancient Monuments of the Mississippi Valley'' (full title ''Ancient Monuments of the Mississippi Valley: Comprising the Results of Extensive Original Surveys and Explorations'') (1848) by the Americans Ephraim George Squier and Edwin Hamilton ...
'', the Institution's first publication.
*1852 – Appointed to the Lighthouse Board
*1871 – Appointed chairman of the Lighthouse Board
Other honors
Elected a member of the American Philosophical Society
The American Philosophical Society (APS), founded in 1743 in Philadelphia, is a scholarly organization that promotes knowledge in the sciences and humanities through research, professional meetings, publications, library resources, and communit ...
in 1835 and American Antiquarian Society
The American Antiquarian Society (AAS), located in Worcester, Massachusetts, is both a learned society and a national research library of pre-twentieth-century American history and culture. Founded in 1812, it is the oldest historical society i ...
in 1851.
The school he attended in Galway, New York was renamed Joseph Henry Elementary School in his honor.
Washington, D.C. named a school, built in 1878–80, on P Street between 6th and 7th the Joseph Henry School; it was demolished at some point after 1932.
The Henry Mountains
The Henry Mountains is a mountain range located in the southeastern portion of the U.S. state of Utah that runs in a generally north-south direction, extending over a distance of about . They were named by Almon Thompson in honor of Joseph Henry ...
(Utah
Utah ( , ) is a state in the Mountain West subregion of the Western United States. Utah is a landlocked U.S. state bordered to its east by Colorado, to its northeast by Wyoming, to its north by Idaho, to its south by Arizona, and to it ...
) had been so named by geologist Almon Thompson in his honor.
Mount Henry in California is named in his honor.
See also
* Electromagnetism
In physics, electromagnetism is an interaction that occurs between particles with electric charge. It is the second-strongest of the four fundamental interactions, after the strong force, and it is the dominant force in the interactions of ...
* Henry (unit)
The henry (symbol: H) is the unit of electrical inductance in the International System of Units (SI). If a current of 1 ampere flowing through a coil produces flux linkage of 1 weber turn, that coil has a self inductance of 1 henry. The unit ...
* Multiple coil magnet
* Timeline of historic inventions
The timeline of historic inventions is a chronological list of particularly important or significant technological inventions and their inventors, where known.
Paleolithic
The dates listed in this section refer to the earliest evidence of an i ...
* Timeline of communication technology
The history of communication technologies (media and appropriate inscription tools) have evolved in tandem with shifts in political and economic systems, and by extension, systems of power. Communication can range from very subtle processes of exc ...
* American Philosophical Society
The American Philosophical Society (APS), founded in 1743 in Philadelphia, is a scholarly organization that promotes knowledge in the sciences and humanities through research, professional meetings, publications, library resources, and communit ...
* History of Albany, New York
The history of Albany, New York began long before the first interaction of Europeans with the native Indian tribes, as they had long inhabited the area. The area was originally inhabited by an Algonquian Indian tribe, the Mohican, as well as the ...
* Daniel Davis Jr. - electrical device inventor
References
Further reading
* Ames, Joseph Sweetman (Ed.), ''The discovery of induced electric currents'', Vol. 1. Memoirs, by Joseph Henry. New York, Cincinnati tc.American book company 1900
As of March 1 ( O.S. February 17), when the Julian calendar acknowledged a leap day and the Gregorian calendar did not, the Julian calendar fell one day further behind, bringing the difference to 13 days until February 28 ( O.S. February 15), 2 ...
LCCN 00005889
* Coulson, Thomas, ''Joseph Henry: His Life and Work'', Princeton, Princeton University Press, 1950
* Dorman, Kathleen W., and Sarah J. Shoenfeld (comps.), ''The Papers of Joseph Henry. Volume 12: Cumulative Index,'' Science History Publications, 2008
* Henry, Joseph, ''Scientific Writings of Joseph Henry. Volumes 1 and 2'', Smithsonian Institution, 1886
* Moyer, Albert E., ''Joseph Henry: The Rise of an American Scientist,'' Washington, Smithsonian Institution Press, 1997.
* Reingold, Nathan, et al., (eds.), ''The Papers of Joseph Henry. Volumes 1-5,'' Washington, Smithsonian Institution Press, 1972–1988
* Rothenberg, Marc, et al., (eds.), ''The Papers of Joseph Henry. Volumes 6-8,'' Washington, Smithsonian Institution Press, 1992–1998, and ''Volumes 9-11,'' Science History Publications, 2002–2007
External links
* Finding aid to th
Joseph Henry collection
at th
University of Pennsylvania Libraries
Biographical details
— ''Proceedings of the National Academy of Sciences'' (1967), 58(1), pp. 1–10.
Dedication ceremony for the Henry statue (1883)
Published physics papers
— ''On the Production of Currents and Sparks of Electricity from Magnetism'' and ''On Electro-Dynamic Induction (extract)''
Joseph Henry Collection, Smithsonian Institution
National Academy of Sciences Biographical Memoir
{{DEFAULTSORT:Henry, Joseph
1797 births
1878 deaths
American people of Scottish descent
American physicists
Burials at Oak Hill Cemetery (Washington, D.C.)
Hall of Fame for Great Americans inductees
Members of the American Antiquarian Society
People associated with electricity
People from Albany, New York
People from Galway, New York
Scientists from New York (state)
Secretaries of the Smithsonian Institution
The Albany Academy alumni
19th-century American physicists
Princeton University faculty