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Christian Church (Disciples of Christ)

The Christian Church (Disciples of Christ) is a mainline Protestant Christian denomination in the United States and Canada. The denomination started with the Restoration Movement during the Second Great Awakening, first existing during the 19th century as a loose association of churches working towards Christian unity, then slowly forming quasi-denominational structures through missionary societies, regional associations, and an international convention. In 1968, the Disciples of Christ officially adopted a denominational structure at which time a group of churches left to remain nondenominational.

The denomination is referred to by several versions of its full name, including "Disciples of Christ", "Disciples", "Christian Church", and "DOC". The Christian Church was a charter participant in the formation of the World Council of Churches (WCC) and of the Federal Council of Churches (now the National Council of Churches), and it continues to be engaged in ecumenical conversations.

The Disciples' local churches are congregationally governed. In 2008 there were 679,563 members in 3,714 congregations in the United States and Canada. By 2015, this number had declined to a baptized membership of 497,423 in 3,267 congregations, of whom about 306,905 were active members, while approximately 177,000 attended Sunday services each week. In 2018, the denomination reported 380,248 members with 124,437 people in average worship attendance. By 2022, membership had dropped to 277,864 members, 89,894 of whom attended worship on average.

History
The Christian Church (Disciples of Christ) traces its roots to the Stone-Campbell Movement on the American frontier. The Movement is so named because it started as two distinct but similar movements, each without knowledge of the other, during the Second Great Awakening in the early 19th century. The first of these two groups, led by Barton W. Stone, began at Cane Ridge, Bourbon County, Kentucky. The group called themselves simply Christians. The second began in western Pennsylvania and Virginia (now West Virginia), led by Thomas Campbell and his son, Alexander Campbell. Because the founders wanted to abandon all denominational labels, they used the biblical names for the followers of Jesus that they found in the Bible.

Stone

In 1801, the Cane Ridge Revival in Kentucky planted the seed for a movement in Kentucky and the Ohio River Valley to disassociate from denominationalism. In 1803 Stone and others withdrew from the Kentucky Presbytery and formed the Springfield Presbytery. The defining event of the Stone wing of the movement was the publication of the Last Will and Testament of the Springfield Presbytery, at Cane Ridge, Kentucky, in 1804. "The Last Will" is a brief document in which Stone and five others announced their withdrawal from Presbyterianism and their intention to be solely part of the body of Christ. The writers appealed for the unity of all who follow Jesus, suggested the value of congregational self-governance, and lifted the Bible as the source for understanding the will of God. They denounced the use of the Westminster Confession of Faith as divisive.

Soon, they adopted the name "Christian" to identify their group. Thus, the remnants of the Springfield Presbytery became the Christian Church. It is estimated that the Christian Church numbered about 12,000 by 1830.

Campbells

Independently of Stone, Thomas Campbell published the Declaration and Address of the Christian Association of Washington, (Pennsylvania) in 1809. In The Declaration and Address, he set forth some of his convictions about the church of Jesus Christ, emphasizing Christian unity and the restoration of the New Testament church. He organized the Christian Association of Washington, not as a church but as an association of persons seeking to grow in faith. On May 4, 1811, however, the Christian Association constituted itself as a congregationally governed church. With the building it then constructed at Brush Run, it became known as Brush Run Church. When their study of the New Testament led the reformers to begin to practice baptism by immersion, the nearby Redstone Baptist Association invited Brush Run Church to join with them for the purpose of fellowship. The reformers agreed provided that they would be "allowed to preach and to teach whatever they learned from the Scriptures."

Thus began a sojourn for the reformers among the Baptists within the Redstone Baptist Association (1815–1824). While the reformers and the Baptists shared the same beliefs in baptism by immersion and congregational polity, it was soon clear that the reformers were not traditional Baptists. Within the Redstone Association, the differences became intolerable to some of the Baptist leaders, when Alexander Campbell began publishing a journal, The Christian Baptist, promoting reform. Campbell anticipated the conflict and moved his membership to a congregation of the Mahoning Baptist Association in 1824.

In 1827, the Mahoning Association appointed reformer Walter Scott as an Evangelist. Through Scott's efforts, the Mahoning Association grew rapidly. In 1828, Thomas Campbell visited several of the congregations formed by Scott and heard him preach. The elder Campbell realized that Scott was bringing an important new dimension to the movement with his approach to evangelism.

Several Baptist associations began disassociating from congregations that refused to subscribe to the Philadelphia Confession. The Mahoning Association came under attack. In 1830, the Mahoning Baptist Association disbanded. Alexander ceased publication of The Christian Baptist. In January 1831, he began publication of the Millennial Harbinger.

1832 Merger

The two groups united at High Street Meeting House, Lexington, Kentucky, with a handshake between Barton W. Stone and "Raccoon" John Smith, on Saturday, December 31, 1831. Smith had been chosen by those present to speak on behalf of the followers of the Campbells. While contemporaneous accounts are clear that the handshake took place on Saturday, some historians have changed the date of the merger to Sunday, January 1, 1832. The 1832 date has become generally accepted. The actual difference is about 20 hours.

Two representatives of those assembled were appointed to carry the news of the union to all the churches: John Rogers for the Christians and "Raccoon" John Smith for the reformers. Despite some challenges, the merger succeeded.

With the merger, there was the challenge of what to call the new movement. Clearly, finding a Biblical, non-sectarian name was important. Stone wanted to continue to use the name "Christians." Alexander Campbell insisted upon "Disciples of Christ". Walter Scott and Thomas Campbell sided with Stone, but the younger Campbell had strong reasons and would not yield. As a result, both names were used.

National Conventions

In 1849, the first National Convention was held at Cincinnati, Ohio. Alexander Campbell had concerns that holding conventions would lead the movement into divisive denominationalism. He did not attend the gathering. Among its actions, the convention elected Alexander Campbell its President and created the American Christian Missionary Society (ACMS).

The formation of a missionary society set the stage for further "co-operative" efforts. By the end of the century, the Foreign Christian Missionary Society and the Christian Women's Board of Missions were also engaged in missionary activities. Forming the ACMS did not reflect a consensus of the entire movement. Sponsorship of missionary activities became a divisive issue. In the succeeding decades, for some congregations and their leaders, co-operative work through missionary societies and the adoption of instrumental music in church worship was straying too far from their conception of the early church. After the American Civil War, the schism grew. While there was no disagreement over the need for evangelism, many believed that missionary societies were not authorized by scripture and would compromise the autonomy of local congregations. This became one important factor leading to the separation of the Churches of Christ from the Christian Church (Disciples of Christ).

Journals
From the beginning of the movement, the free exchange of ideas among the people was fostered by the journals published by its leaders. Alexander Campbell published the Christian Baptist and the Millennial Harbinger. Barton W. Stone published the Christian Messenger. In a respectful way, both men routinely published the contributions of others whose positions were radically different from their own.

Following Campbell's death in 1866, journals continued to keep the discussion and conversation alive. Between 1870 and 1900, two journals emerged as the most prominent. The Christian Standard was edited and published by Isaac Errett of Cincinnati. The Christian Evangelist was edited and published by J. H. Garrison from St. Louis. The two men enjoyed a friendly rivalry, and kept the dialog going within the movement. A third journal became part of the conversation with the publication in 1884 of The Christian Oracle, later to become The Christian Century, with an interdenominational appeal. In 1914, Garrison's Christian Publishing company was purchased by R. A. Long, who then established a non-profit corporation, "The Christian Board of Publication" as the Brotherhood publishing house.

First Division
In 1906, the U.S. Religious Census listed Churches of Christ for the first time as a group which was separate and distinct from the Disciples of Christ. However, the division had been growing for years, with published reports as early as 1883. The most obvious distinction between the two groups was the Churches of Christ rejecting the use of musical instruments in worship. The controversy over musical instruments began in 1860, when some congregations introduced organs, traditionally associated with wealthier, denominational churches. More basic were the underlying approaches to Biblical interpretation. The Churches of Christ permitted only those practices found in accounts of New Testament worship. They could find no New Testament documentation of the use of instrumental music in worship. The Disciples, by contrast, considered permissible any practices that the New Testament did not expressly forbid. While music and the approach to missionary work were the most visible issues, there were also some deeper ones. The process that led to the separation had begun prior to the American Civil War.

The Brotherhood
In the early 20th century, a central point of conflict for the remaining Christian Churches was cooperative missionary efforts, both nationally and internationally. Several missionary societies had already been established, and the congregations that contributed to these societies and attended the national convention became known as "cooperative" and began referring to the larger grouping of these congregations as "the Brotherhood." In 1917 the National Convention became the International Convention of Christian Churches (Disciples of Christ) with the incorporation of Canadian Disciples. In 1920, three separate missionary societies merged into the United Christian Missionary Society in 1920, which undertook missions work both in the "homeland" and abroad. Over the next fifty years, the UCMS was the largest agency of the Brotherhood. The National Benevolent Association was also established during the early 20th century as a social services ministry providing assistance to orphans, the elderly and the disabled.

The congregations that did not participate were known as "independents." Until the cooperative churches underwent the process of restructure in the 1960s, the cooperatives and independents coexisted together under the same identity, but were following different paths by the 1940s, with the independents forming the North American Christian Convention in 1947.

While issues of ecclesiology were at the forefront of the growing division, theological issues also divided the two groups, with the cooperative churches largely adopting the new methods of Biblical analysis developed in the late 19th century.

Restructure
Following World War II, it became obvious that the organizations that had been developed in previous decades no longer effectively met the needs of the postwar era. After a number of discussions throughout the 1950s, the 1960 International Convention of Christian Churches adopted a process to "restructure" the entire organization. The Commission on Restructure, chaired by Granville T. Walker, held its first meeting on October 30 & November 1, 1962. In 1968, the International Convention of Christian Churches (Disciples of Christ) adopted the commission's proposed Provisional Design of the Christian Church (Disciples of Christ). Soon The Provisional Design became The Design.

The Brotherhood's adoption of The Design made the earlier split between the cooperative and independent churches official. Under The Design, all churches in the 1968 yearbook of Christian Churches (Disciples of Christ) were automatically recognized as part of the Christian Church (Disciples of Christ). In the years that followed, many of the Independent Christian Church Congregations requested formal withdrawal from the yearbook. Many of those congregations were already part of the North American Christian Convention; this group would become known as the Christian churches and churches of Christ and became the third primary group of the Stone-Campbell Movement.

Logo
In 1971, the General Assembly adopted a logo for the denomination. The logo depicts a red chalice with a white St. Andrew's Cross. Symbolically the chalice is said to represent the Lord's Supper, which is central to Disciples practice, and the cross of St. Andrew is said to represent the denomination's roots in Scottish Presbyterian and the ministry of all people. The logo was designed by Ronald E. Osborn who drew the logo with a red pen, leading to the red color of the logo, and refined by Bruce Tilsley. The logo can be used by all Disciples congregations, ministries, and other affiliated institutions and provides clarity among confusion from the "Christian Church" moniker many Disciple and non-Disciple congregations use.

Beliefs and practices
As a congregational denomination, each Disciples congregation determines the nature of its worship, study, Christian service, and witness to the world. Through belief in the priesthood of all believers, Disciples also practice freedom of interpretation among its members, with only baptism and confession of Christ as Lord required.

Doctrine and interpretation
Early members of the Stone-Campbell Movement adopted the slogan "In essentials, Unity; In non-essentials, Liberty; and in all things, Charity." For modern disciples the one essential is the acceptance of Jesus Christ as Lord and Savior, and obedience to him in baptism. There is no requirement to give assent to any other statement of belief or creed. Nor is there any official interpretation of the Bible. Hierarchical doctrine was traditionally rejected by Disciples as human-made and divisive, and subsequently, freedom of belief and scriptural interpretation allows many Disciples to question or even deny beliefs common in doctrinal churches such as the Incarnation, the Trinity, and the Atonement. Beyond the essential commitment to follow Jesus, there is a tremendous freedom of belief and interpretation. As the basic teachings of Jesus are studied and applied to life, there is the freedom to interpret Jesus' teaching in different ways. As would be expected from such an approach, there is a wide diversity among Disciples in what individuals and congregations believe. It is not uncommon to find individuals who seemingly hold diametrically opposed beliefs within the same congregation affirming one another's journeys of faith as sisters and brothers in Christ.

Modern Disciples reject the use of creeds as "tests of faith", that is, as required beliefs, necessary to be accepted as a follower of Jesus. Although Disciples respect the great creeds of the church as informative affirmations of faith, they are never seen as binding. Since the adoption of The Design of the Christian Church (Disciples of Christ), in 1968, Disciples have celebrated a sense of unity in reading the preamble to the Design publicly.

Worship and Communion
Most congregations sing hymns, read from the Old and New Testaments, hear the word of God proclaimed through sermon or other medium and extend an invitation to become Christ's Disciples.

Most Disciple congregations practice weekly celebrations of the Lord's Supper, often referred to by Disciples as Communion, as an integral part of worship. Through the observance of Communion, individuals are invited to acknowledge their faults and sins, to remember the death and resurrection of Jesus Christ, to remember their baptism, and to give thanks for God's redeeming love. Because Disciples believe that the invitation to the table comes from Jesus Christ, Communion is open to all who confess that Jesus Christ is Lord, regardless of their denominational affiliation.

Baptism
Most Disciple congregations practice believer's baptism in the form of immersion, believing it to be the form used in the New Testament. The experiences of yielding to Christ in being buried with him in the waters of baptism and rising to a new life have profound meaning for the church. While most congregations exclusively practice baptism by immersion, Disciples also accept other forms of baptism including infant baptism.

Ecumenical efforts
The Disciples celebrate their oneness with all who seek God through Jesus Christ, throughout time and regardless of location. In local communities, congregations share with churches of other denominations in joint worship and in community Christian service. Ecumenical cooperation and collaboration with other Christian Communions has long been practiced by the Regions.

At the General Church level, the Christian Unity and Interfaith Ministries Unity (CUIM) coordinates the ecumenical and interfaith activities of the church. The Disciples continues to relate to the National Council of Churches and Canadian Council of Churches, both of which it was a founding member. It shares in the dialog and in the theological endeavors of the World Council of Churches. The Disciples has been a full participant in the Consultation on Church Union since it began in the 1960s. It continues to support those ongoing conversations which have taken on the title Churches Uniting in Christ.

The Disciples have two full communion partners: the United Church of Christ, since 1989, and the United Church of Canada, since 2019. These three denominations all share mutual full communion with each other. CUIM describes these partnerships as the proclamation of "mutual recognition of their sacraments and ordained ministry." Ordained Disciple ministers are able to directly serve in the United Church of Christ without having to seek additional qualifications.

Additionally, the Disciples combined their overseas ministries with the United Church of Christ in 1996. Known as Global Ministries, it is a common agency of both denominations with a joint staff and is a continuance of decades of cooperative work in global missions.

While the Disciples of Christ and United Church of Canada have entered full communion, the recentness of the agreement means that the provisions for mutual recognition of clergy are not yet finalized and adopted.

Ordained ministry
The Disciples believe in the priesthood of all believers, in that all people baptized are called to minister to others with diverse spiritual gifts. The Disciples view their Order of Ministry as a specific subset of all believers who are called with spiritual gifts specifically suited for pastoral ministry. Congregations use different terms to refer to persons in the Order of Ministry including Pastor and Reverend but most call them Ministers, including the denomination's governing documents.

Congregations sponsor members seeking ordination or commissioning as a Minister, and Regional Ministries organize committees to oversee the process. Ordination can be achieved by obtaining a Master of Divinity from a theological institution, which does not have to be an institution associated with the Disciples. Ordination can also be achieved through an "Apprentice" track which has candidates shadow ordained ministers. Finally, Ministers can be Commissioned, a shorter process for seminary students and those seeking short-term ministry in a Region. Regional requirements for ministry vary. Ordination is made official through a service which includes members of the church, clergy, and Regional Minister laying their hands on the candidate as the ordaining act. Ecumenical representatives are often included to emphasize the Disciples' desire for Christian unity.

Disciples recognize the ordinations of the United Church of Christ as do they for Disciples.

A General Commission on the Order of Ministry exists to interpret and review definitions of ministry, give oversight to Regions and congregations, provide other support, and maintain the standing of Regional Ministers and Ministers of General (National) Ministries.

LGBTQ inclusion
In 1977, the General Assembly of the denomination debated resolutions about homosexuality for the first time; a resolution condemning the "homosexual lifestyle" was defeated by the Assembly and a resolution to ban gay people from the ordained ministry was referred to the General Minister and President for further study. At the next General Assembly two years later, the Assembly approved a resolution that declared "The ordination of persons who engage in homosexual practices is not in accord with God's will," but concurrently declared that "The Christian Church (Disciples of Christ) intends to continue the current pattern of assigning responsibility to the regions with respect to the nurture, certification, and ordination of ministers." Since then, some regions have ordained LGBTQ ministers before the denomination officially supported it. Concerns about LGBTQ people continued to be an issue at the General Assembly, but resolutions that called on more civil rights protections for LGBTQ people were passed with overwhelming majorities and resolutions to ban the "homosexual lifestyle" continued to be rejected.

In 2011, the Christian Church (Disciples of Christ) stated that "Disciples do not have a formal policy on same-sex marriage. Different congregations have the autonomy to discern on issues such as this one." In 2013, the Disciples of Christ voted in favor of a resolution affirming all members regardless of sexual orientation. After same-sex marriage was legalized in the US, the denomination reiterated that it leaves "all decisions of policy on same-sex marriage to local congregations".

In 2019, the General Assembly passed a resolution specifically affirming that transgender and gender non-conforming people are welcome in the Christian Church (Disciples of Christ).

Disciples LGBTQ+ Alliance provides resources to congregations that want to be certified as "Open and Affirming" to show that they are accepting of all gender identities and sexual orientations. The Alliance was founded as the Gay, Lesbian, and Affirming Disciples Alliance (GLAD) during the 1979 General Assembly. The Disciples of Christ supports the right to an abortion.

Structure
The structure of the Disciples is unique among Mainline Protestant churches. The Design, the governing document of the denomination, describes three "expressions" of the church: congregational, regional, and general. Each of these expressions are "characterized by its integrity, self-governance, authority, rights, and responsibilities." In relating to each other, they work in covenant and not authority to support the ministry and work of the church.

Congregations
Congregations of the Disciples are self-governing in the tradition of congregational polity. They call their own Ministers, select their own leadership, own their own property, and manage their own affairs.

In Disciples congregations, the priesthood of all believers finds its expression in worship and Christian service. Congregations elect and ordain lay persons as Elders to share in duties of congregational ministry with the staff ministers, including visiting the sick and administering communion to them, providing spiritual guidance for the congregation, and presiding over Communion during worship, either with or without the staff ministers.

Regional Ministries
Regional churches consist of all Disciples in a given area, usually a state or group of states. As of 2023, the denomination has 31 regions, including the Christian Church (Disciples of Christ) in Canada which has a dual identity as a region in the binational church and a national denomination in its own right.

Regions meet in a Regional Assembly every two to three years to conduct business. Each Region calls a Regional Minister to serve as its primary pastor and chief executive; most regions also have Associate Regional Ministers and other staff to serve specific aspects of its ministries. Canada calls its regional minister a "national pastor". Regions are analogous to the middle judicatories of other denominations, and Regional Ministers are analogous to Bishops.

One of the primary responsibilities of the Regions is the care for and oversight of clergy. The Design places primary responsibility for ordination and licensing of ministers with the region. Candidates seeking ordination are sponsored by a congregation but must be approved by their region, which usually entails a process of interviews and other evaluations by a committee made up of clergy and lay people. The Regional Minister usually officiates the ordination service in the sponsoring congregation. After ordination, regions continue to oversee clergy through a process known as standing, which requires ministers to undergo certain trainings periodically and maintain membership in a Disciples congregation. Ministers can lose their standing for violating the ministerial code of ethics the denomination maintains. Finally, Regional Ministers often provide pastoral care to ministers in their region.

Regions also nurture congregations in their region, including planting new churches, providing guidance, supporting struggling congregations, and helping congregations hire their ministers. This latter process consists of a system known as Search and Call, in which ministers seeking a church declare which regions they would like to serve in and the region then suggests those candidates to congregations seeking a minister. Regional Ministers usually provides congregations with a set of candidates that they feel will meet the congregation's particular needs.

Regions also provide fellowship and education opportunities for its members. Many regions have summer camping experiences for children and youth.

As with all parts of the Disciples, Regions do not have authority to control congregations and congregations are not required to use regional programming, including the search and call system.

General Ministries
The Christian Church (Disciples of Christ) at the "General Church" level consists of a number of self-governing agencies, which focus upon specific Christian witnesses to the world. The church agencies report to the General Assembly, which meets biennially in odd-numbered years and is an assembly of representatives selected by congregations and ordained ministers with standing in the denomination. The General Minister and President (GMP) is the lead pastor for the denomination and the chief executive officer of the legal corporation. Following the covenantal understanding of the denomination, the GMP does not have direct executive power over the General Ministries, regions, or congregations. The GMP is elected to a six-year term by the General Assembly, with the option for a second term.

The current General Minister and President is Teresa Hord Owens. When she was elected in 2017, Owens was the first black woman to lead a mainline denomination as their chief executive. Her presidency followed the presidency of Sharon E. Watkins, the first woman to lead a mainline denomination as their chief executive.

The General Ministries are:
 * Office of the General Minister and President: executive office for the denomination and includes communications, fundraising for the denominational mission fund, Week of Compassion, and anti-racist/pro-reconciliation efforts
 * Central Pastoral Office for Hispanic Ministries-Obra Hispana: promotes, undergirds, and coordinates work of Disciples Hispanic Ministries and Spanish speaking and bilingual congregations
 * Christian Board of Publication-Chalice Press: denominational publishing house
 * Christian Church Foundation: provides assistance on giving and endowments
 * Christian Unity and Interfaith Ministry (formerly the Council on Christian Unity): ecumenical and interfaith engagement and dialogue
 * Disciples Church Extension Fund: support for congregational finances, new church ministry, and congregational renewal
 * Disciples Home Missions: provides support for congregational and local ministries including education and faith formation, church vocations, environmental justice, immigration and refugee ministries, families and children, youth, young adults, men's and women's ministries, and volunteering.
 * Disciples of Christ Historical Society: maintains archives for the denomination and the larger Stone-Campbell Movement
 * Division of Overseas Ministries-Global Ministries: global mission and volunteer work in joint partnership with the United Church of Christ
 * Higher Education and Leadership Ministries: works with higher education partners and theological education partners and provides leadership development
 * National Benevolent Association: partners with and connects independent health and social service ministries to Disciples and each other
 * National Convocation: historical association of Black Disciple congregations that merged with the White Disciples in 1968, now continues as an association connecting and supporting black members and congregations
 * North American Pacific/Asian Disciples: association of Pacific and Asian-American Disciples members and congregations
 * Pension Fund of the Christian Church: provides pensions and investment/savings products to clergy and lay employees of Stone-Campbell/Restoration Movement churches and organizations.

One highly popular and respected General Agency program is the "Week of Compassion," named for the special offering to fund the program when it began in the 1950s. The Week of Compassion is the disaster relief and Third World development agency. It works closely with Church World Service and church-related organizations in countries around the world where disasters strike, providing emergency aid.

The General Church has challenged the entire denomination to work for a 2020 Vision for the first two decades of the 21st century. Together the denomination is well on the way to achieving its four foci:
 * Seeking racial justice, which it describes as becoming a pro-reconciling/anti-racist church.
 * Forming 1,000 new congregations across the United States and Canada by 2020.
 * Seeking God's transformation of 1,000 existing Congregations in ways that will renew their witness.
 * Working to nurture leadership for newly formed and transformed congregations.

Membership trends
The Christian Church (Disciples of Christ) has experienced a very significant loss of membership since the middle of the 20th century. Membership peaked in 1958 at just under 2 million. In 1993, membership dropped below 1 million. In 2009, the denomination reported 658,869 members in 3,691 congregations. In 2010, the five states with the highest adherence rates were Kansas, Missouri, Iowa, Kentucky and Oklahoma. The states with the largest absolute number of adherents were Missouri, Texas, Indiana, Kentucky and Ohio. In 2017, membership had declined to 450,425 members.

Affiliated academic institutions
From the very beginnings of the movement, Disciples have founded institutions of higher learning. Alexander Campbell taught young leaders and founded Bethany College. The movement established similar schools, especially in the years following the American Civil War.

Because intellectual and religious freedom are important values for the Disciples of Christ, the colleges, universities, and seminaries founded by its congregations do not seek to indoctrinate students or faculty with a sectarian point of view.

In the 21st century, the relationship between the Christian Church (Disciples of Christ) and its affiliated universities is the purview of Higher Education and Leadership Ministries (HELM), an agency of the General Church.

Universities and colleges

 * Barton College – Wilson, North Carolina
 * Bethany College – Bethany, West Virginia
 * Chapman University – Orange, California
 * Columbia College – Columbia, Missouri
 * Culver-Stockton College – Canton, Missouri
 * Drury University – Springfield, Missouri
 * Eureka College – Eureka, Illinois
 * Hiram College – Hiram, Ohio
 * Jarvis Christian College – Hawkins, Texas
 * University of Lynchburg – Lynchburg, Virginia
 * Midway University – Midway, Kentucky
 * Texas Christian University – Fort Worth, Texas
 * Tougaloo College – Tougaloo, Mississippi
 * Transylvania University – Lexington, Kentucky
 * William Woods University – Fulton, Missouri

Seminaries and theological institutions
The Disciples have four seminaries and divinity schools directly affiliated with the denomination. These institutions have an ecumenical student body, a reflection of the Disciples' focus on church unity. They are:
 * Brite Divinity School – Fort Worth, Texas
 * Christian Theological Seminary – Indianapolis, Indiana
 * Lexington Theological Seminary – Lexington, Kentucky
 * Phillips Theological Seminary – Tulsa, Oklahoma

The Disciples have three additional institutions that provide supplementary education and community living for ecumenical theological institutions. They are:
 * Disciples Divinity House of the University of Chicago, affiliated with the University of Chicago Divinity School – Chicago, Illinois
 * Disciples Divinity House at Vanderbilt, affiliated with the Vanderbilt Divinity School – Nashville, Tennessee
 * Disciples Seminary Foundation, affiliated with Claremont School of Theology, Iliff School of Theology, Pacific School of Religion, and San Francisco Theological Seminary – Claremont, California

Ecumenical relations
The Disciples of Christ maintains ecumenical relations with the Pontifical Council for Promoting Christian Unity. It is also affiliated with other ecumenical organizations such as Churches Uniting in Christ, Christian Churches Together, the National Council of Churches and the World Council of Churches. It maintains Ordained Ministerial Partner Standing with the United Church of Christ, which means that clergy ordained in the Disciples of Christ may also serve in the United Church of Christ. Since 2019, it has been a full Communion partner and had an agreement for mutual recognition of ministerial credentials with the United Church of Canada. It is affiliated with the Disciples Ecumenical Consultative Council and the World Communion of Reformed Churches.

Prominent members

 * Jesse Moren Bader, evangelist
 * William Barber II, Disciples pastor and President of North Carolina NAACP
 * Andy Beshear, current Governor of Kentucky
 * Edgar Cayce, American mystic
 * Fred Craddock, professor and preacher
 * Elmira J. Dickinson, American missionary and advocate for temperance
 * J. William Fulbright, U.S. Senator from Arkansas
 * James A. Garfield, 20th President of the United States, ordained Disciples minister, Principal (President) of Western Reserve Eclectic Institute (now named Hiram College) in Hiram, Ohio
 * Murry Hammond, singer
 * Grey DeLisle, voice actress
 * Dean Hess, US Air Force Pilot
 * Ben Hogan, professional golfer, tied for fourth all-time with nine career professional major championships
 * Archie Ijames, assistant pastor of Jim Jones' Peoples Temple.
 * Jan Jensen (basketball), current head coach, Iowa Women's Basketball.
 * Lyndon Baines Johnson, 36th President of the United States
 * Jim Jones, cult leader, who was ordained as a Disciples minister before the denomination was organized in 1968; at that time requirements for ordination varied greatly in different regions and congregations. Two investigations were undertaken in 1974 and 1977 by the denomination that did not find any wrongdoings. No rules or precedent existed for the Disciples for removing ministers, and the Disciples responded to the Jonestown mass killings with significant changes for ministerial ethics and the process to remove ministers from the list of ordained.
 * Marinda Lemert (1811–1891), religious writer who argued for the ordination of women
 * Frances McDormand, actress; winner of the Triple Crown of Acting
 * James Clark McReynolds, United States Supreme Court Justice (1914–1941)
 * Harold Bell Wright, early 20th century author; pastor at churches in the association prior to becoming an author. The author is best known for the novel The Shepherd of the Hills, and is the first fiction author to sell 1 million copies.
 * John Muir, Scottish founder of the environmental movement. Raised in the church, but later left it.
 * Francis Gary Powers, American CIA U-2 spy plane pilot shot down while flying a reconnaissance mission in Soviet Union airspace
 * Betsy Price, former mayor of Fort Worth, Texas (2011–2021), the 16th most populous city in the United States
 * Ronald Reagan, 40th President of the United States, baptized into the Disciples as a youth, and graduated from the Disciples' Eureka College, but a member of Bel Air Presbyterian Church in his later years. He married Nancy at The Little Brown Church in Studio City, California, a Disciples Church.
 * Susanna Carson Rijnhart, Tibetan explorer, missionary
 * Gene Robinson, raised in a Disciples church, later joined the Episcopal Church in the United States of America and became the first openly gay priest to be consecrated as a bishop in a major Christian denomination believing in the historic episcopate
 * Colonel Harlan Sanders, founder of Kentucky Fried Chicken
 * Tom Selleck, actor
 * John Stamos, actor
 * Preston Taylor, African American minister, businessperson and philanthropist; founder of the National Christian Missionary Convention
 * William Thomas Jr., actor
 * Marion Tinsley, considered the all-time greatest human checkers player
 * Jessie Trout, Canadian missionary in Japan, author, Japanese-American internment camp worker, co-founder of the Christian Women's Fellowship (1950) and the International Christian Women's Fellowship (1953)
 * Emily Harvie Thomas Tubman, businesswoman and philanthropist from Augusta, Georgia, early supporter of the Restoration Movement and correspondent of Alexander Campbell. She financed the construction of many Christian churches in the United States and donated to several Disciples-affiliated colleges.
 * Roger Williams (U.S. politician), Congressman representing Texas' 25th District in the U.S. House of Representatives. Former Secretary of State of Texas (2004–2007)
 * John Wooden, legendary UCLA basketball coach, raised in a Disciples Church in Martinsville, Indiana
 * Bruce Zager, former justice, Iowa Supreme Court.

title: Christian Church (Disciples of Christ)


text:
David Rice Atchison

David Rice Atchison (August 11, 1807 – January 26, 1886) was a mid-19th century Democratic United States Senator from Missouri. He served as President pro tempore of the United States Senate for six years. Atchison served as a major general in the Missouri State Militia in 1838 during Missouri's Mormon War and as a Confederate brigadier general during the American Civil War under Major General Sterling Price in the Missouri Home Guard. Some of Atchison's associates claimed that for 24 hours—Sunday, March 4, 1849, through noon on Monday—he may have been Acting President of the United States. This belief, however, is dismissed by nearly all scholars.

Atchison, owner of many slaves and a plantation, was a prominent pro-slavery activist and Border Ruffian leader, deeply involved with violence against abolitionists and other free-staters during the "Bleeding Kansas" events that preceded admission of the state to the Union.

Early life
Atchison was born to William Atchison and his wife in Frogtown (later Kirklevington), which is now part of Lexington, Kentucky. He was educated at Transylvania University in Lexington. Classmates included five future Democratic senators (Solomon Downs of Louisiana, Jesse Bright of Indiana, George Wallace Jones of Iowa, Edward Hannegan of Indiana, and Jefferson Davis of Mississippi). Atchison completed law studies and was admitted to the Kentucky bar in 1829.

Missouri lawyer and politician
In 1830 he moved to Liberty in Clay County in western Missouri, and set up practice there. He also acquired a farm or plantation, with labor provided by enslaved African Americans. Atchison's law practice flourished, and his best-known client was Joseph Smith, founder of the Latter Day Saint Movement. Atchison represented Smith in land disputes with non-Mormon settlers in Caldwell County and Daviess County.

Alexander William Doniphan joined Atchison's law practice in Liberty in May 1833. The two became fast friends and spent many leisure time hours playing cards, going to horse races, hunting, fishing, and attending social functions and political events. Atchison, already a member of the Liberty Blues, a volunteer militia in Missouri, got Doniphan to join.

Atchison was elected to the Missouri House of Representatives in 1834. He worked hard for the Platte Purchase, which required Native American tribes to cede land to the United States and extended the northwestern boundary of Missouri to the Missouri River in 1837.

When early disputes broke out into the Mormon War of 1838, Atchison was appointed a major general in the state militia. He took part in suppressing violence by both sides.

Active in the Democratic Party, in 1838 Atchison was re-elected to the Missouri State House of Representatives. In 1841, he was appointed a circuit court judge for the six-county area of the Platte Purchase. In 1843 he was named a county commissioner in Platte County, where he then lived.

Senate career
In October 1843, Atchison was appointed to the U.S. Senate to fill the vacancy left by the death of Lewis F. Linn. He was the first senator from western Missouri to serve in this position. At age 36, he was the youngest senator from Missouri up to that time. Atchison was re-elected to a full term on his own account in 1849.

Atchison was very popular with his fellow Senate Democrats. When the Democrats took control of the US Senate in December 1845, they chose Atchison as President pro tempore, placing him second in succession for the Presidency. He also was responsible for presiding over the Senate when the Vice President was absent. At 38, he was a young man with low seniority in the Senate after two years to gain such a position.

In 1849 Atchison stepped down as President pro tempore in favor of William R. King. King in turn yielded the office back to Atchison in December 1852, after being elected Vice President of the United States. Atchison continued as President pro tempore until December 1854.

As a Senator, Atchison was a fervent advocate of slavery and territorial expansion. He supported the annexation of Texas and the U.S.-Mexican War. Atchison and Thomas Hart Benton, Missouri's other Senator, became rivals and finally enemies, although both were Democrats. Benton declared himself to be against slavery in 1849. In 1851 Atchison allied with the Whigs to defeat incumbent Benton for re-election.

Benton, intending to challenge Atchison in 1854, began to agitate for territorial organization of the area west of Missouri (now the states of Kansas and Nebraska) so that it could be opened to settlement. To counter this, Atchison proposed that the area be organized and that the section of the Missouri Compromise banning slavery there be repealed in favor of popular sovereignty. Under this plan, settlers in each territory would vote to decide whether they would allow slavery.

At Atchison's request, Senator Stephen Douglas of Illinois introduced the Kansas–Nebraska Act, which embodied this idea, in November 1853. The Act was passed and became law in May 1854, establishing the Territories of Kansas and Nebraska.

Border Ruffians
Both Douglas and Atchison had believed that Nebraska would be settled by Free-State men from Iowa and Illinois, and Kansas by pro-slavery Missourians and other Southerners, thus preserving the numerical balance between free states and slave states in the nation. In 1854 Atchison helped found the town of Atchison, Kansas, as a pro-slavery settlement. The town (and county) were named for him.

While Southerners supported the idea of settling Kansas, few migrated there. Most free-soilers preferred Kansas to Nebraska. Furthermore, anti-slavery activists throughout the North came to view Kansas as a battleground and formed societies to encourage free-soil settlers to go to Kansas, to ensure there would be enough voters in both Kansas and Nebraska to approve their entry as free states.

It appeared as if the Kansas Territorial legislature to be elected in March 1855 would be controlled by free-soilers and ban slavery. This was viewed as a breach of faith by Atchison and his supporters. An angry Atchison called on pro-slavery Missourians to uphold slavery by force and "to kill every God-damned abolitionist in the district" if necessary. He recruited an immense mob of heavily armed Missourians, the infamous "Border Ruffians". On the election day, March 30, 1855, Atchison led 5,000 Border Ruffians into Kansas. They seized control of all polling places at gunpoint, cast tens of thousands of fraudulent votes for pro-slavery candidates, and elected a pro-slavery legislature.

The outrage was nonetheless accepted by the Federal government. When Territorial Governor Andrew Reeder objected, he was fired by President Franklin Pierce.

Despite this show of force, far more free-soilers than pro-slavery settlers migrated to Kansas. There were continual raids and ambushes by both sides in "Bleeding Kansas". In spite of the best efforts of Atchison and the Ruffians, Kansas rejected slavery and finally became a free state in 1861.

Charles Sumner, in the epic "Crimes Against Kansas" speech on May 19, 1856, exposed Atchison's role in the invasion, tortures, and killings in Kansas. Speaking in the flamboyant style he and others used, lacing his prose with references to Roman history, Sumner compared Atchison to Roman Senator Catiline, who betrayed his country in a plot to overthrow the existing order. For two days, Sumner listed crime, after crime, in detail, complete with documentation by newspapers and letters of the time, showing the tortures and violence by Atchison and his men.

Two days later, Atchison gave his own speech, totally unaware as yet that he was exposed on Senate floor in such a fashion. Atchison's speech was to the Texas men he just met, hired and paid for, Atchison reveals in his speech, by "authorities in Washington". They are about to invade Lawrence, Kansas. Atchison makes the men promise to kill and "draw blood," and boasts of his flag, which was red in color for "Southern Rights" and the color of blood. They would press "to blood" the spread of slavery into Kansas. He revealed in this speech that the immediate goal of the invasion was to stop the newspaper in Lawrence from publishing anti-slavery material. Atchison's men had made it a crime to publish anti-slavery newspapers in Kansas.

Atchison made it clear the men are to kill and draw blood, told the men they will be "well paid," and encouraged them to plunder from the homes that they invaded. That was after the hundreds of dozens of tortures and killings that Sumner had detailed in his Crimes Against Kansas speech. In other words, things were about to get much worse since Atchison had his hired men from Texas.

Defeated for re-election
Atchison's Senate term expired on March 3, 1855. He sought election to another term, but the Democrats in the Missouri legislature were split between him and Benton, while the Whig minority put forward their own man. No Senator was elected until January 1857, when James S. Green was chosen.

Railroad proposal
When the first transcontinental railroad was proposed in the 1850s, Atchison called for it to be built along the central route (from St. Louis through Missouri, Kansas, and Utah), rather than the southern route (from New Orleans through Texas and New Mexico). Naturally, his suggested route went through Atchison.

American Civil War
Atchison and his law partner Doniphan fell out over politics in 1859–1861, disagreeing on how Missouri should proceed. Atchison favored secession, while Doniphan was torn and would remain for the most part non-committal. Privately Doniphan favored the Union, but found it difficult to oppose his friends and associates.

During the secession crisis in Missouri at the beginning of the American Civil War, Atchison sided with Missouri's pro-Confederate governor, Claiborne Jackson. He was appointed a major general in the Missouri State Guard. Atchison actively recruited State Guardsmen in northern Missouri and served with Guard commander General Sterling Price in the summer campaign of 1861. In September 1861, Atchison led 3,500 State Guard recruits across the Missouri River to reinforce Price, and defeated Union troops that tried to block his force in the Battle of Liberty.

Atchison served in the State Guard through the end of 1861. In March 1862, Union forces in the Trans-Mississippi theater won a decisive victory at Pea Ridge in Arkansas and secured Union control of Missouri. Atchison then resigned from the army over reported strategy arguments with Price and moved to Texas for the duration of the war. After the war he retired to his farm near Gower. He denied many of his pro-slavery public statements made prior to the Civil War. Then, his retirement cottage outside of Plattsburg, Missouri burned to the ground before his death in 1886. This entailed the complete loss of his library containing books, documents, and letters which documented his role in the Mormon War, Indian affairs, pro-slavery activities, Civil War activities, and other legislation covering his career as a lawyer, senator, and soldier.

Purported one-day presidency
Inauguration Day—March 4—fell on a Sunday in 1849, and so president-elect Zachary Taylor did not take the presidential oath of office until the next day. Even so, the term of the outgoing president, James K. Polk, ended at noon on March 4. On March 2, outgoing vice president George M. Dallas relinquished his position as president of the Senate. Congress had previously chosen Atchison as president pro tempore. In 1849, according to the Presidential Succession Act of 1792, the Senate president pro tempore immediately followed the vice president in the presidential line of succession. As Dallas's term also ended at noon on the 4th, and as neither Taylor nor vice president-elect Millard Fillmore had been sworn in to office on that day, it was claimed by some of Atchison's friends and colleagues that on March 4–5, 1849, Atchison was acting president of the United States.

Historians, constitutional scholars and biographers all dismiss the claim. They point out that Atchison's Senate term had also ended on March 4. When the Senate of the new Congress convened on March 5 to allow new senators and the new vice president to take the oath of office, the secretary of the Senate called members to order, as the Senate had no president pro tempore. Although an incoming president must take the oath of office before any official acts, the prevailing view is that presidential succession does not depend on the oath. Even supposing that an oath were necessary, Atchison never took it, so he was no more the president than Taylor.

In September 1872, Atchison, who never himself claimed that he was technically president, told a reporter for the Plattsburg Lever: "It was in this way: Polk went out of office on March 3, 1849, on Saturday at 12 noon. The next day, the 4th, occurring on Sunday, Gen. Taylor was not inaugurated. He was not inaugurated till Monday, the 5th, at 12 noon. It was then canvassed among Senators whether there was an interregnum (a time during which a country lacks a government). It was plain that there was either an interregnum or I was the President of the United States being chairman of the Senate, having succeeded Judge Mangum of North Carolina. The judge waked me up at 3 o'clock in the morning and said jocularly that as I was President of the United States he wanted me to appoint him as secretary of state. I made no pretense to the office, but if I was entitled in it I had one boast to make, that not a woman or a child shed a tear on account of my removing any one from office during my incumbency of the place. A great many such questions are liable to arise under our form of government."

Death
Atchison died on January 26, 1886, at his home near Gower, Missouri at the age of 78. He was buried at Greenlawn Cemetery in Plattsburg, Missouri. His grave marker reads "President of the United States for One Day."

Legacy

 * Atchison, Kansas county seat of Atchison County, Kansas
 * Atchison County, Missouri
 * USS Atchison County (LST-60) ship
 * In 1991, Atchison was inducted into the Hall of Famous Missourians, and a bronze bust depicting him is on permanent display in the rotunda of the Missouri State Capitol.
 * Atchison County Historical Museum in Atchison, Kansas includes a museum exhibit, jokingly titled the "World's Smallest Presidential Library" devoted to Atchison.
 * A historical marker designating the approximate site of Atchison's birth is located along Highway 1974 in the Landsdowne neighborhood of Lexington, Kentucky.

license: Creative Commons - Attribution Share-Alike - https://creativecommons.org/licenses/by-sa/4.0/

title: David Rice Atchison


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Daniel Gabriel Fahrenheit

Daniel Gabriel Fahrenheit FRS (24 May 1686 – 16 September 1736) was a physicist, inventor, and scientific instrument maker, born in Poland to a family of German extraction. Fahrenheit invented thermometers accurate and consistent enough to allow the comparison of temperature measurements between different observers using different instruments. Fahrenheit is also credited with inventing mercury-in-glass thermometers more accurate and superior to spirit-filled thermometers at the time. The popularity of his thermometers led to the widespread adoption of his Fahrenheit scale attached to his instruments.

Early life
Fahrenheit was born in Danzig (Gdańsk), then in the Polish–Lithuanian Commonwealth. The Fahrenheits were a German Hanse merchant family who had lived in several Hanseatic cities. Fahrenheit's great-grandfather had lived in Rostock, and research suggests that the Fahrenheit family originated in Hildesheim. Daniel's grandfather moved from Kneiphof in Königsberg (present-day Kaliningrad) to Danzig and settled there as a merchant in 1650. His son, Daniel Fahrenheit (the father of Daniel Gabriel), married Concordia Schumann, the daughter of a well-known Danzig business family. Daniel was the eldest of the five Fahrenheit children (two sons, three daughters) who survived childhood. His sister, Virginia Elisabeth Fahrenheit, married Benjamin Krüger and was the mother of Benjamin Ephraim Krüger, a clergyman and playwright.

As a young adult, Fahrenheit "showed a particular desire for studying," and was scheduled to enroll in the Danzig Gymnasium. But on 14 August 1701, his parents died after eating poisonous mushrooms. Fahrenheit, along with two brothers and sisters, was placed under guardianship. In 1702, Fahrenheit's guardians enrolled him in a bookkeeping course and sent him to a four-year merchant trade apprenticeship in Amsterdam.

Upon completing his apprenticeship, Fahrenheit ran off and began a period of travel through Germany, Sweden, and Denmark in 1707. At the request of his guardians, a warrant was issued for his arrest with the intention of placing him into the service of the Dutch East India company.

Work with thermometers, Fahrenheit scale
By around 1706, Fahrenheit was manufacturing and shipping barometers and spirit-filled thermometers using the Florentine temperature scale. In 1708, Fahrenheit met with the mayor of Copenhagen and astronomer, Ole Rømer, and was introduced to Rømer's temperature scale and his methods for making thermometers. Rømer told Fahrenheit that demand for accurate thermometers was high. The visit inspired Fahrenheit to try to improve his own offerings. Perhaps not coincidentally, Fahrenheit's arrest warrant was dropped around the time of his meeting with Rømer.

In 1709, Fahrenheit returned to Danzig and took observations using his barometers and thermometers, traveled more in 1710 and returned to Danzig in 1711 to settle his parents' estate. After additional travel to Königsberg and Mitau in 1711, he returned to Danzig in 1712 and stayed there for two years. During this period he worked on solving technical problems with his thermometers.

Fahrenheit began experimenting with mercury thermometers in 1713. Also by this time, Fahrenheit was using a modified version of Rømer's scale for his thermometers which would later evolve into his own Fahrenheit scale. In 1714, Fahrenheit left Danzig for Berlin and Dresden to work closely with the glass-blowers there. In that year Christian Wolff wrote about Fahrenheit's thermometers in a journal after receiving a pair of his alcohol-based devices, helping to boost Fahrenheit's reputation in the scientific community.

In addition to his interest in meteorological instruments, Fahrenheit also worked on his ideas for a mercury clock, a perpetual motion machine, and a heliostat around 1715. He struck up a correspondence with Leibniz about some of these projects. From the exchange of letters, we learn that Fahrenheit was running out of money while working on his projects and asked Leibniz for help obtaining a paid post so he could continue his work.

In 1717 or 1718, Fahrenheit returned to Amsterdam and began selling barometers, areometers, and his mercury and alcohol-based thermometers commercially. By 1721, Fahrenheit had perfected the process of crafting and standardizing his thermometers. The superiority of his mercury thermometers over alcohol-based thermometers made them very popular, leading to the widespread adoption of his Fahrenheit scale, the measurement system he developed and used for his thermometers.

Later life and controversy
Fahrenheit spent the remainder of his life in Amsterdam. From 1718 onward, he lectured in chemistry in Amsterdam. He visited England in 1724 and was elected into the Fellow of the Royal Society on May 5. In August of that year, he published five papers in Latin for the Royal Society's scientific journal, Philosophical Transactions, on various topics. In his second paper, Experimenta et observationes de congelatione aquae in value factae, he provides a description of his thermometers and the reference points he used for calibrating them. For two centuries, this document was the only description of Fahrenheit's process for making thermometers. In the 20th century, Ernst Cohen uncovered correspondences between Fahrenheit and Herman Boerhaave which cast considerable doubt on the veracity of Fahrenheit's article explaining the reference points for his scale and that, in fact, Fahrenheit's scale was largely derived from Rømer's scale. In his book, The History of the Thermometer and Its Use in Meteorology, W. E. Knowles Middleton writes,

"I believe that much of the confusion [over the Fahrenheit scale] has resulted from believing that [Fahrenheit] meant exactly what he said [in his Royal Society article], and discounting the natural tendency of an instrumentmaker to wish to conceal his processes, or at least to obfuscate his readers."

From August 1736 to his death, Fahrenheit stayed in the house of Johannes Frisleven at Plein Square in The Hague in connection with an application for a patent at the States of Holland and West Friesland. At the beginning of September, he became ill and on the 7th his health had deteriorated to such an extent that he had notary Willem Ruijsbroek come to draw up his will. On the 11th, the notary came by again to make some changes. Five days after that, Fahrenheit died at the age of fifty. Four days later, he received the fourth-class funeral of one who is classified as destitute, in the Kloosterkerk in The Hague (the Cloister or Monastery Church).

Fahrenheit scale
According to Fahrenheit's 1724 article, he determined his scale by reference to three fixed points of temperature. The lowest temperature was achieved by preparing a frigorific mixture of ice, water, and a salt ("ammonium chloride or even sea salt"), and waiting for the eutectic system to reach equilibrium temperature. The thermometer then was placed into the mixture and the liquid in the thermometer allowed to descend to its lowest point. The thermometer's reading there was taken as 0 °F. The second reference point was selected as the reading of the thermometer when it was placed in still water when ice was just forming on the surface. This was assigned as 30 °F. The third calibration point, taken as 90 °F, was selected as the thermometer's reading when the instrument was placed under the arm or in the mouth.

Fahrenheit came up with the idea that mercury boils around 300 degrees on this temperature scale. Work by others showed that water boils about 180 degrees above its freezing point. The Fahrenheit scale later was redefined to make the freezing-to-boiling interval exactly 180 degrees, a convenient value as 180 is a highly composite number, meaning that it is evenly divisible into many fractions. It is because of the scale's redefinition that normal mean body temperature today is taken as 98.6 degrees, whereas it was 96 degrees on Fahrenheit's original scale.

The Fahrenheit scale was the primary temperature standard for climatic, industrial and medical purposes in English-speaking countries until the 1970s, presently mostly replaced by the Celsius scale long used in the rest of the world, apart from the United States, where temperatures and weather reports are still broadcast in Fahrenheit.

title: Daniel Gabriel Fahrenheit


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Freescale DragonBall

Motorola/Freescale Semiconductor's DragonBall, or MC68328, is a microcontroller design based on the famous 68000 core, but implemented as an all-in-one low-power system for handheld computer use. It is supported by μClinux. It was designed by Motorola in Hong Kong and released in 1995.

The DragonBall's major design win was in numerous devices running the Palm OS platform. However, from Palm OS 5 onwards their use was superseded by ARM-based processors from Texas Instruments and Intel.

The processor is capable of speeds of up to 16.58 MHz and can run up to 2.7 MIPS (million instructions per second), for the base 68328 and DragonBall EZ (MC68EZ328) model. It was extended to 33 MHz, 5.4 MIPS for the DragonBall VZ (MC68VZ328) model, and 66 MHz, 10.8 MIPS for the DragonBall Super VZ (MC68SZ328).

It is a 32-bit processor with 32-bit internal and external address bus (24-bit external address bus for EZ and VZ variants) and 32-bit data bus (8/16-bit external data bus). It has many built-in functions, like a color and grayscale display controller, PC speaker sound, serial port with UART and IRDA support, UART bootstrap, real time clock, is able to directly access DRAM, Flash ROM, mask ROM, and has built-in support for touch screens.

The more recent DragonBall MX series microcontrollers, later renamed the Freescale i.MX (MC9328MX/MCIMX) series, are intended for similar application to the earlier DragonBall devices but are based on an ARM processor core instead of a 68000 core.

title: Freescale DragonBall


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Double-slit experiment

In modern physics, the double-slit experiment demonstrates that light and matter can satisfy the seemingly incongruous classical definitions for both waves and particles. This ambiguity is considered evidence for the fundamentally probabilistic nature of quantum mechanics. This type of experiment was first performed by Thomas Young in 1801, as a demonstration of the wave behavior of visible light. In 1927, Davisson and Germer and, independently George Paget Thomson and his research student Alexander Reid demonstrated that electrons show the same behavior, which was later extended to atoms and molecules. Thomas Young's experiment with light was part of classical physics long before the development of quantum mechanics and the concept of wave–particle duality. He believed it demonstrated that Christiaan Huygens' wave theory of light was correct, and his experiment is sometimes referred to as Young's experiment or Young's slits.

The experiment belongs to a general class of "double path" experiments, in which a wave is split into two separate waves (the wave is typically made of many photons and better referred to as a wave front, not to be confused with the wave properties of the individual photon) that later combine into a single wave. Changes in the path-lengths of both waves result in a phase shift, creating an interference pattern. Another version is the Mach–Zehnder interferometer, which splits the beam with a beam splitter.

In the basic version of this experiment, a coherent light source, such as a laser beam, illuminates a plate pierced by two parallel slits, and the light passing through the slits is observed on a screen behind the plate. The wave nature of light causes the light waves passing through the two slits to interfere, producing bright and dark bands on the screen – a result that would not be expected if light consisted of classical particles. However, the light is always found to be absorbed at the screen at discrete points, as individual particles (not waves); the interference pattern appears via the varying density of these particle hits on the screen. Furthermore, versions of the experiment that include detectors at the slits find that each detected photon passes through one slit (as would a classical particle), and not through both slits (as would a wave). However, such experiments demonstrate that particles do not form the interference pattern if one detects which slit they pass through. These results demonstrate the principle of wave–particle duality.

Other atomic-scale entities, such as electrons, are found to exhibit the same behavior when fired towards a double slit. Additionally, the detection of individual discrete impacts is observed to be inherently probabilistic, which is inexplicable using classical mechanics.

The experiment can be done with entities much larger than electrons and photons, although it becomes more difficult as size increases. The largest entities for which the double-slit experiment has been performed were molecules that each comprised 2000 atoms (whose total mass was 25,000 atomic mass units).

The double-slit experiment (and its variations) has become a classic for its clarity in expressing the central puzzles of quantum mechanics. Because it demonstrates the fundamental limitation of the ability of the observer to predict experimental results, Richard Feynman called it "a phenomenon which is impossible […] to explain in any classical way, and which has in it the heart of quantum mechanics. In reality, it contains the only mystery [of quantum mechanics]."

Overview
If light consisted strictly of ordinary or classical particles, and these particles were fired in a straight line through a slit and allowed to strike a screen on the other side, we would expect to see a pattern corresponding to the size and shape of the slit. However, when this "single-slit experiment" is actually performed, the pattern on the screen is a diffraction pattern in which the light is spread out. The smaller the slit, the greater the angle of spread. The top portion of the image shows the central portion of the pattern formed when a red laser illuminates a slit and, if one looks carefully, two faint side bands. More bands can be seen with a more highly refined apparatus. Diffraction explains the pattern as being the result of the interference of light waves from the slit.

If one illuminates two parallel slits, the light from the two slits again interferes. Here the interference is a more pronounced pattern with a series of alternating light and dark bands. The width of the bands is a property of the frequency of the illuminating light. (See the bottom photograph to the right.)

When Thomas Young (1773–1829) first demonstrated this phenomenon, it indicated that light consists of waves, as the distribution of brightness can be explained by the alternately additive and subtractive interference of wavefronts. Young's experiment, performed in the early 1800s, played a crucial role in the understanding of the wave theory of light, vanquishing the corpuscular theory of light proposed by Isaac Newton, which had been the accepted model of light propagation in the 17th and 18th centuries.

However, the later discovery of the photoelectric effect demonstrated that under different circumstances, light can behave as if it is composed of discrete particles. These seemingly contradictory discoveries made it necessary to go beyond classical physics and take into account the quantum nature of light.

Feynman was fond of saying that all of quantum mechanics can be gleaned from carefully thinking through the implications of this single experiment. He also proposed (as a thought experiment) that if detectors were placed before each slit, the interference pattern would disappear.

The Englert–Greenberger duality relation provides a detailed treatment of the mathematics of double-slit interference in the context of quantum mechanics.

A low-intensity double-slit experiment was first performed by G. I. Taylor in 1909, by reducing the level of incident light until photon emission/absorption events were mostly non-overlapping.

A slit interference experiment was not performed with anything other than light until 1961, when Claus Jönsson of the University of Tübingen performed it with coherent electron beams and multiple slits. In 1974, the Italian physicists Pier Giorgio Merli, Gian Franco Missiroli, and Giulio Pozzi performed a related experiment using single electrons from a coherent source and a biprism beam splitter, showing the statistical nature of the buildup of the interference pattern, as predicted by quantum theory. In 2002, the single-electron version of the experiment was voted "the most beautiful experiment" by readers of Physics World. Since that time a number of related experiments have been published, with a little controversy.

In 2012, Stefano Frabboni and co-workers sent single electrons onto nanofabricated slits (about 100 nm wide) and, by detecting the transmitted electrons with a single-electron detector, they could show the build-up of a double-slit interference pattern. Many related experiments involving the coherent interference have been performed; they are the basis of modern electron diffraction, microscopy and high resolution imaging.

In 2018, single particle interference was demonstrated for antimatter in the Positron Laboratory (L-NESS, Politecnico di Milano) of Rafael Ferragut in Como (Italy), by a group led by Marco Giammarchi.

Interference from individual particles
An important version of this experiment involves single particle detection. Sending coherent particles through a double-slit apparatus one at a time results in single particles being detected as white dots on the screen, as expected. Remarkably, however, an interference pattern emerges when these particles are allowed to build up one by one (see the image below).

This is actually the only way for particles to create the interference pattern in the experiment, as they only interfere with themselves and never with each other even when several particles are sent through the double slit at once (the only exception is when the particles are entangled) This demonstrates the wave–particle duality, which states that all matter exhibits both wave and particle properties: The particle is measured as a single pulse at a single position, while the modulus squared of the wave describes the probability of detecting the particle at a specific place on the screen giving a statistical interference pattern. This phenomenon has been shown to occur with photons, electrons, atoms, and even some molecules: with buckminsterfullerene in 2001,   with 2 molecules of 430 atoms ( and ) in 2011, and with molecules of up to 2000 atoms in 2019.

Mach-Zehnder interferometer
The Mach–Zehnder interferometer can be seen as a simplified version of the double-slit experiment. Instead of propagating through free space after the two slits, and hitting any position in an extended screen, in the interferometer the photons can only propagate via two paths, and hit two discrete photodetectors. This makes it possible to describe it via simple linear algebra in dimension 2, rather than differential equations.

A photon emitted by the laser hits the first beam splitter and is then in a superposition between the two possible paths. In the second beam splitter these paths interfere, causing the photon to hit the photodetector on the right with probability one, and the photodetector on the bottom with probability zero. It is interesting to consider what would happen if the photon were definitely in either of paths between the beam splitters. This can be accomplished by blocking one of the paths, or equivalently by detecting the presence of a photon there. In both cases there will be no interference between the paths anymore, and both photodetectors will be hit with probability 1/2. From this we can conclude that the photon does not take one path or another after the first beam splitter, but rather that it is in a genuine quantum superposition of the two paths.

"Which-way" experiments and the principle of complementarity
A well-known thought experiment predicts that if particle detectors are positioned at the slits, showing through which slit a photon goes, the interference pattern will disappear. This which-way experiment illustrates the complementarity principle that photons can behave as either particles or waves, but cannot be observed as both at the same time. Despite the importance of this thought experiment in the history of quantum mechanics (for example, see the discussion on Einstein's version of this experiment), technically feasible realizations of this experiment were not proposed until the 1970s. (Naive implementations of the textbook thought experiment are not possible because photons cannot be detected without absorbing the photon.) Currently, multiple experiments have been performed illustrating various aspects of complementarity.

An experiment performed in 1987 produced results that demonstrated that partial information could be obtained regarding which path a particle had taken without destroying the interference altogether. This "wave-particle trade-off" takes form of an inequality relating the visibility of the interference pattern and the distinguishability of the which-way paths.

Delayed choice and quantum eraser variations
Wheeler's delayed-choice experiments demonstrate that extracting "which path" information after a particle passes through the slits can seem to retroactively alter its previous behavior at the slits.

Quantum eraser experiments demonstrate that wave behavior can be restored by erasing or otherwise making permanently unavailable the "which path" information.

A simple do-it-at-home illustration of the quantum eraser phenomenon was given in an article in Scientific American. If one sets polarizers before each slit with their axes orthogonal to each other, the interference pattern will be eliminated. The polarizers can be considered as introducing which-path information to each beam. Introducing a third polarizer in front of the detector with an axis of 45° relative to the other polarizers "erases" this information, allowing the interference pattern to reappear. This can also be accounted for by considering the light to be a classical wave, and also when using circular polarizers and single photons. Implementations of the polarizers using entangled photon pairs have no classical explanation.

Weak measurement
In a highly publicized experiment in 2012, researchers claimed to have identified the path each particle had taken without any adverse effects at all on the interference pattern generated by the particles. In order to do this, they used a setup such that particles coming to the screen were not from a point-like source, but from a source with two intensity maxima. However, commentators such as Svensson have pointed out that there is in fact no conflict between the weak measurements performed in this variant of the double-slit experiment and the Heisenberg uncertainty principle. Weak measurement followed by post-selection did not allow simultaneous position and momentum measurements for each individual particle, but rather allowed measurement of the average trajectory of the particles that arrived at different positions. In other words, the experimenters were creating a statistical map of the full trajectory landscape.

Other variations

In 1967, Pfleegor and Mandel demonstrated two-source interference using two separate lasers as light sources.

It was shown experimentally in 1972 that in a double-slit system where only one slit was open at any time, interference was nonetheless observed provided the path difference was such that the detected photon could have come from either slit. The experimental conditions were such that the photon density in the system was much less than 1.

In 1991, Carnal and Mlynek performed the classic Young's double slit experiment with metastable helium atoms passing through micrometer-scale slits in gold foil.

In 1999, a quantum interference experiment (using a diffraction grating, rather than two slits) was successfully performed with buckyball molecules (each of which comprises 60 carbon atoms). A buckyball is large enough (diameter about 0.7 nm, nearly half a million times larger than a proton) to be seen in an electron microscope.

In 2002, an electron field emission source was used to demonstrate the double-slit experiment. In this experiment, a coherent electron wave was emitted from two closely located emission sites on the needle apex, which acted as double slits, splitting the wave into two coherent electron waves in a vacuum. The interference pattern between the two electron waves could then be observed. In 2017, researchers performed the double-slit experiment using light-induced field electron emitters. With this technique, emission sites can be optically selected on a scale of ten nanometers. By selectively deactivating (closing) one of the two emissions (slits), researchers were able to show that the interference pattern disappeared.

In 2005, E. R. Eliel presented an experimental and theoretical study of the optical transmission of a thin metal screen perforated by two subwavelength slits, separated by many optical wavelengths. The total intensity of the far-field double-slit pattern is shown to be reduced or enhanced as a function of the wavelength of the incident light beam.

In 2012, researchers at the University of Nebraska–Lincoln performed the double-slit experiment with electrons as described by Richard Feynman, using new instruments that allowed control of the transmission of the two slits and the monitoring of single-electron detection events. Electrons were fired by an electron gun and passed through one or two slits of 62 nm wide × 4 μm tall.

In 2013, a quantum interference experiment (using diffraction gratings, rather than two slits) was successfully performed with molecules that each comprised 810 atoms (whose total mass was over 10,000 atomic mass units). The record was raised to 2000 atoms (25,000 amu) in 2019.

Hydrodynamic pilot wave analogs
Hydrodynamic analogs have been developed that can recreate various aspects of quantum mechanical systems, including single-particle interference through a double-slit. A silicone oil droplet, bouncing along the surface of a liquid, self-propels via resonant interactions with its own wave field. The droplet gently sloshes the liquid with every bounce. At the same time, ripples from past bounces affect its course. The droplet's interaction with its own ripples, which form what is known as a pilot wave, causes it to exhibit behaviors previously thought to be peculiar to elementary particles – including behaviors customarily taken as evidence that elementary particles are spread through space like waves, without any specific location, until they are measured.

Behaviors mimicked via this hydrodynamic pilot-wave system include quantum single particle diffraction, tunneling, quantized orbits, orbital level splitting, spin, and multimodal statistics. It is also possible to infer uncertainty relations and exclusion principles. Videos are available illustrating various features of this system. (See the External links.)

However, more complicated systems that involve two or more particles in superposition are not amenable to such a simple, classically intuitive explanation. Accordingly, no hydrodynamic analog of entanglement has been developed. Nevertheless, optical analogs are possible.

Double-slit experiment on time
In 2023, an experiment was reported recreating an interference pattern in time by shining a pump laser pulse at a screen coated in indium tin oxide (ITO) which would alter the properties of the electrons within the material due to the Kerr effect, changing it from transparent to reflective for around 200 femtoseconds long where a subsequent probe laser beam hitting the ITO screen would then see this temporary change in optical properties as a slit in time and two of them as a double slit with a phase difference adding up destructively or constructively on each frequency component resulting in an interference pattern. Similar results have been obtained classically on water waves.

Classical wave-optics formulation

Much of the behaviour of light can be modelled using classical wave theory. The Huygens–Fresnel principle is one such model; it states that each point on a wavefront generates a secondary wavelet, and that the disturbance at any subsequent point can be found by summing the contributions of the individual wavelets at that point. This summation needs to take into account the phase as well as the amplitude of the individual wavelets. Only the intensity of a light field can be measured—this is proportional to the square of the amplitude.

In the double-slit experiment, the two slits are illuminated by the quasi-monochromatic light of a single laser. If the width of the slits is small enough (much less than the wavelength of the laser light), the slits diffract the light into cylindrical waves. These two cylindrical wavefronts are superimposed, and the amplitude, and therefore the intensity, at any point in the combined wavefronts depends on both the magnitude and the phase of the two wavefronts. The difference in phase between the two waves is determined by the difference in the distance travelled by the two waves.

If the viewing distance is large compared with the separation of the slits (the far field), the phase difference can be found using the geometry shown in the figure below right. The path difference between two waves travelling at an angle $θ$ is given by:

 * $$d \sin \theta \approx d \theta$$

Where d is the distance between the two slits. When the two waves are in phase, i.e. the path difference is equal to an integral number of wavelengths, the summed amplitude, and therefore the summed intensity is maximum, and when they are in anti-phase, i.e. the path difference is equal to half a wavelength, one and a half wavelengths, etc., then the two waves cancel and the summed intensity is zero. This effect is known as interference. The interference fringe maxima occur at angles

 * $$~ d \theta_n = n \lambda,~ n=0,1,2,\ldots$$

where λ is the wavelength of the light. The angular spacing of the fringes, $θ_{f}$, is given by

 * $$ \theta_f \approx \lambda / d $$

The spacing of the fringes at a distance $z$ from the slits is given by

 * $$~w=z \theta_f = z \lambda /d$$

For example, if two slits are separated by 0.5 mm ($d$), and are illuminated with a 0.6 μm wavelength laser ($λ$), then at a distance of 1 m ($z$), the spacing of the fringes will be 1.2 mm.

If the width of the slits $b$ is appreciable compared to the wavelength, the Fraunhofer diffraction equation is needed to determine the intensity of the diffracted light as follows:

\begin{align} I(\theta) &\propto \cos^2 \left [{\frac {\pi d \sin \theta}{\lambda}}\right]~\mathrm{sinc}^2 \left [ \frac {\pi b \sin \theta}{\lambda} \right] \end{align} $$

where the sinc function is defined as sinc(x) = sin(x)/x for x ≠ 0, and sinc(0) = 1.

This is illustrated in the figure above, where the first pattern is the diffraction pattern of a single slit, given by the $sinc$ function in this equation, and the second figure shows the combined intensity of the light diffracted from the two slits, where the $cos$ function represents the fine structure, and the coarser structure represents diffraction by the individual slits as described by the $sinc$ function.

Similar calculations for the near field can be made by applying the Fresnel diffraction equation, which implies that as the plane of observation gets closer to the plane in which the slits are located, the diffraction patterns associated with each slit decrease in size, so that the area in which interference occurs is reduced, and may vanish altogether when there is no overlap in the two diffracted patterns.

Path-integral formulation

The double-slit experiment can illustrate the path integral formulation of quantum mechanics provided by Feynman. The path integral formulation replaces the classical notion of a single, unique trajectory for a system, with a sum over all possible trajectories. The trajectories are added together by using functional integration.

Each path is considered equally likely, and thus contributes the same amount. However, the phase of this contribution at any given point along the path is determined by the action along the path: $$A_{\text{path}}(x,y,z,t) = e^{i S(x,y,z,t)}$$

All these contributions are then added together, and the magnitude of the final result is squared, to get the probability distribution for the position of a particle: $$p(x,y,z,t) \propto \left\vert \int_{\text{all paths}} e^{i S(x,y,z,t)} \right\vert ^2 $$

As is always the case when calculating probability, the results must then be normalized by imposing: $$\iiint_{\text{all space}}p(x,y,z,t)\,dV = 1$$

The probability distribution of the outcome is the normalized square of the norm of the superposition, over all paths from the point of origin to the final point, of waves propagating proportionally to the action along each path. The differences in the cumulative action along the different paths (and thus the relative phases of the contributions) produces the interference pattern observed by the double-slit experiment. Feynman stressed that his formulation is merely a mathematical description, not an attempt to describe a real process that we can measure.

Interpretations of the experiment
Like the Schrödinger's cat thought experiment, the double-slit experiment is often used to highlight the differences and similarities between the various interpretations of quantum mechanics.

Copenhagen interpretation
The Copenhagen interpretation is a collection of views about the meaning of quantum mechanics, stemming from the work of Niels Bohr, Werner Heisenberg, Max Born, and others. The term "Copenhagen interpretation" was apparently coined by Heisenberg during the 1950s to refer to ideas developed in the 1925–1927 period, glossing over his disagreements with Bohr. Consequently, there is no definitive historical statement of what the interpretation entails. Features common across versions of the Copenhagen interpretation include the idea that quantum mechanics is intrinsically indeterministic, with probabilities calculated using the Born rule, and the principle of complementarity, which states that objects have certain pairs of complementary properties that cannot all be observed or measured simultaneously. Moreover, the act of "observing" or "measuring" an object is irreversible, and no truth can be attributed to an object, except according to the results of its measurement. A particular experiment can demonstrate particle behavior (passing through a definite slit) or wave behavior (interference), but not both at the same time. Copenhagen-type interpretations hold that quantum descriptions are objective, in that they are independent of physicists' personal beliefs and other arbitrary mental factors.

The results from the most basic double slit experiment, the observation of an interference pattern, is explained by wave interference from the two paths to the screen from each of the two slits. The single-particle results show that the waves are probability amplitudes which square to produce a probability distribution. The particles are discrete and identical; many are needed to build up the full interference pattern. The results from some of the which-way experiments are described as observations of complementarity: modifying the experiment to monitor the slit suppresses the interference pattern. Other which-way experiments make no mention of complementarity in their analysis.

Relational interpretation
According to the relational interpretation of quantum mechanics, first proposed by Carlo Rovelli, observations such as those in the double-slit experiment result specifically from the interaction between the observer (measuring device) and the object being observed (physically interacted with), not any absolute property possessed by the object. In the case of an electron, if it is initially "observed" at a particular slit, then the observer–particle (photon–electron) interaction includes information about the electron's position. This partially constrains the particle's eventual location at the screen. If it is "observed" (measured with a photon) not at a particular slit but rather at the screen, then there is no "which path" information as part of the interaction, so the electron's "observed" position on the screen is determined strictly by its probability function. This makes the resulting pattern on the screen the same as if each individual electron had passed through both slits.

Many-worlds interpretation
As with Copenhagen, there are multiple variants of the many-worlds interpretation. The unifying theme is that physical reality is identified with a wavefunction, and this wavefunction always evolves unitarily, i.e., following the Schrödinger equation with no collapses. Consequently, there are many parallel universes, which only interact with each other only through interference. David Deutsch argues that the way to understand the double-slit experiment is that in each universe the particle travels through a specific slit, but its motion is affected by the interference with particles in other universes. This creates the observable fringes. David Wallace, another advocate of the many-worlds interpretation, writes that in the familiar setup of the double-slit experiment the two paths are not sufficiently separated for a description in terms of parallel universes to make sense.

De Broglie–Bohm theory
An alternative to the standard understanding of quantum mechanics, the De Broglie–Bohm theory states that particles also have precise locations at all times, and that their velocities are defined by the wave-function. So while a single particle will travel through one particular slit in the double-slit experiment, the so-called "pilot wave" that influences it will travel through both. The two slit de Broglie-Bohm trajectories were first calculated by Chris Dewdney while working with Chris Philippidis and Basil Hiley at Birkbeck College (London). The de Broglie-Bohm theory produces the same statistical results as standard quantum mechanics, but dispenses with many of its conceptual difficulties by adding complexity through an ad hoc quantum potential to guide the particles.

While the model is in many ways similar to Schrödinger equation, it is known to fail for relativistic cases and does not account for features such as particle creation or annihilation in quantum field theory. Many authors such as nobel laureates Werner Heisenberg, Sir Anthony James Leggett and Sir Roger Penrose have criticized it for not adding anything new.

More complex variants of this type of approach have appeared, for instance the three wave hypothesis of Ryszard Horodecki as well as other complicated combinations of de Broglie and Compton waves. To date there is no evidence that these are useful.

Interactive animations

 * Huygens and interference

Single particle experiments

 * Website with the movie and other information from the first single electron experiment by Merli, Missiroli, and Pozzi.
 * Movie showing single electron events build up to form an interference pattern in double-slit experiments. Several versions with and without narration (File size = 3.6 to 10.4 MB) (Movie Length = 1m 8s)
 * Freeview video 'Electron Waves Unveil the Microcosmos' A Royal Institution Discourse by Akira Tonomura provided by the Vega Science Trust
 * Hitachi website that provides background on Tonomura video and link to the video

Hydrodynamic analog

 * "Single-particle interference observed for macroscopic objects"
 * Pilot-Wave Hydrodynamics: Supplemental Video
 * Through the Wormhole: Yves Couder . Explains Wave/Particle Duality via Silicon Droplets

Computer simulations

 * Java demonstration of Young's double slit interference
 * A simulation that runs in Mathematica Player, in which the number of quantum particles, the frequency of the particles, and the slit separation can be independently varied

title: Double-slit experiment