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128-675: The United States Lighthouse Board was the second agency of the U.S. federal government , under the Department of Treasury , responsible for the construction and maintenance of all lighthouses and navigation aids in the United States , between 1852 and 1910. The new agency was created following complaints of the shipping industry of the previous administration of lighthouses under the Treasury's Lighthouse Establishment , which had had jurisdiction since 1791, and since 1820, been under

256-640: A U.S. citizen for at least seven years, and must live in the state that they represent. In addition to the 435 voting members, there are six non-voting members, consisting of five delegates and one resident commissioner . There is one delegate each from Washington, D.C. , Guam , the Virgin Islands , American Samoa , the Commonwealth of the Northern Mariana Islands , and a resident commissioner from Puerto Rico . Unlike

384-707: A complex set of relationships between state and federal courts. Federal courts can sometimes hear cases arising under state law pursuant to diversity jurisdiction , state courts can decide certain matters involving federal law, and a handful of federal claims are primarily reserved by federal statute to the state courts. Both court systems have exclusive jurisdiction in some areas and concurrent jurisdiction in others. The U.S. Constitution safeguards judicial independence by providing that federal judges shall hold office "during good behavior"; in practice, this usually means they serve until they die, retire, or resign. A judge who commits an offense while in office may be impeached in

512-432: A constant light (from a fixed lens), one flash per minute (from a rotating lens with eight panels), and two per minute (16 panels). In late 1825, to reduce the loss of light in the reflecting elements, Fresnel proposed to replace each mirror with a catadioptric prism, through which the light would travel by refraction through the first surface, then total internal reflection off the second surface, then refraction through

640-523: A constitutional interpretation by the courts. One of the theoretical pillars of the U.S. Constitution is the idea of " checks and balances " among the powers and responsibilities of the three branches of American government: the executive, the legislative, and the judiciary. For example, while the legislative branch ( Congress ) has the power to create law, the executive branch under the president can veto any legislation—an act which, in turn, can be overridden by Congress. The president nominates judges to

768-414: A conventional lens by dividing the lens into a set of concentric annular sections. An ideal Fresnel lens would have an infinite number of sections. In each section, the overall thickness is decreased compared to an equivalent simple lens. This effectively divides the continuous surface of a standard lens into a set of surfaces of the same curvature, with stepwise discontinuities between them. In some lenses,

896-455: A cylindrical form while retaining the property of reflecting light from a single point back to that point. Reflectors of this form, paradoxically called "dioptric mirrors", proved particularly useful for returning light from the landward side of the lamp to the seaward side. As lighthouses proliferated, they became harder to distinguish from each other, leading to the use of colored filters, which wasted light. In 1884, John Hopkinson eliminated

1024-613: A few cases. The judicial power extends to cases arising under the Constitution, an Act of Congress ; a U.S. treaty ; cases affecting ambassadors , ministers and consuls of foreign countries in the U.S.; cases and controversies to which the federal government is a party; controversies between states (or their citizens) and foreign nations (or their citizens or subjects); and bankruptcy cases (collectively "federal-question jurisdiction"). The Eleventh Amendment removed from federal jurisdiction cases in which citizens of one state were

1152-401: A focal length of 920 mm ( 36 + 1 ⁄ 4  in) and stands about 2.59 m (8 ft 6 in) high, and 1.8 m (6 ft) wide. The smallest (sixth) order has a focal length of 150 mm (6 in) and a height of 433 mm ( 17 + 1 ⁄ 16  in). The largest Fresnel lenses are called hyperradiant (or hyper-radial). One such lens was on hand when it

1280-916: A junior officer of the Navy to act as Secretary to said board, whose duty it shall be under instructions from the Treasury Department to inquire into the condition of the Lighthouse Establishment of the United States, and make a general detailed report and programme to guide legislation in extending and improving our present system of construction, illumination, inspection, and superintendence. The Lighthouse Board resulted from this mandate, and its original members consisted of William B. Shubrick , and Samuel F. Du Pont , U.S. Navy; James Kearney, U.S. Topographical Engineers; civilian academics Alexander Dallas Bache , Superintendent of

1408-414: A metal housing, a reflector, a lamp assembly, and a Fresnel lens. Many Fresnel instruments allow the lamp to be moved relative to the lens' focal point , to increase or decrease the size of the light beam. As a result, they are very flexible, and can often produce a beam as narrow as 7° or as wide as 70°. The Fresnel lens produces a very soft-edged beam, so is often used as a wash light. A holder in front of

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1536-570: A million ships". The first person to focus a lighthouse beam using a lens was apparently the London glass-cutter Thomas Rogers, who proposed the idea to Trinity House in 1788. The first Rogers lenses, 53   cm in diameter and 14   cm thick at the center, were installed at the Old Lower Lighthouse at Portland Bill in 1789. Behind each lamp was a back-coated spherical glass mirror, which reflected rear radiation back through

1664-615: A more limited role for the central government in relation to individuals, the states, or other recognized entities. Since the American Civil War , the powers of the federal government have generally expanded greatly, although there have been periods since that time of legislative branch dominance (e.g., the decades immediately following the Civil War) or when states' rights proponents have succeeded in limiting federal power through legislative action, executive prerogative or by

1792-859: A position. Perhaps the most widespread use of Fresnel lenses, for a time, occurred in automobile headlamps , where they can shape the roughly parallel beam from the parabolic reflector to meet requirements for dipped and main-beam patterns, often both in the same headlamp unit (such as the European H4 design). For reasons of economy, weight, and impact resistance, newer cars have dispensed with glass Fresnel lenses, using multifaceted reflectors with plain polycarbonate lenses. However, Fresnel lenses continue in wide use in automobile tail, marker, and reversing lights. Glass Fresnel lenses also are used in lighting instruments for theatre and motion pictures (see Fresnel lantern ); such instruments are often called simply Fresnels . The entire instrument consists of

1920-486: A rotating array outside the fixed array. Each panel of the rotating array was to refract part of the fixed light from a horizontal fan into a narrow beam. Also in 1825, Fresnel unveiled the Carte des Phares ('lighthouse map'), calling for a system of 51 lighthouses plus smaller harbor lights, in a hierarchy of lens sizes called "orders" (the first being the largest), with different characteristics to facilitate recognition:

2048-478: A single elected term." Under the Presentment Clause of Article I, a bill that passes both chambers of Congress shall be presented to the president, who may sign the bill into law or veto the bill by returning it to the chamber where it originated. If the president neither signs nor vetoes a bill "within ten Days (Sundays excepted) after it shall have been presented to him" it becomes a law without

2176-557: A substantial reduction in thickness (and thus mass and volume of material) at the expense of reducing the imaging quality of the lens, which is why precise imaging applications such as photography usually still use larger conventional lenses. Fresnel lenses are usually made of glass or plastic; their size varies from large (old historical lighthouses, meter size) to medium (book-reading aids, OHP viewgraph projectors) to small ( TLR / SLR camera screens, micro-optics). In many cases they are very thin and flat, almost flexible, with thicknesses in

2304-426: Is based on the principles of federalism and republicanism , in which power is shared between the federal government and state governments . The interpretation and execution of these principles, including what powers the federal government should have and how those powers can be exercised, have been debated ever since the adoption of the Constitution. Some make a case for expansive federal powers while others argue for

2432-459: Is on. They attach to the passenger-side window. Another automobile application of a Fresnel lens is a rear view enhancer, as the wide view angle of a lens attached to the rear window permits examining the scene behind a vehicle, particularly a tall or bluff-tailed one, more effectively than a rear-view mirror alone. Fresnel lenses have been used on rangefinding equipment and projected map display screens. Fresnel lenses have also been used in

2560-569: Is sometimes used. The terms "Federal" and "National" in government agency or program names generally indicate affiliation with the federal government; for instance, the Federal Bureau of Investigation , National Oceanic and Atmospheric Administration , and National Park Service . Because the seat of government is in Washington, D.C. , "Washington" is sometimes used as a metonym for the federal government. The United States government

2688-475: Is the double-flashing lens of the Point Arena Light , which was in service from 1908 to 1977. The development of hyper-radial lenses was driven in part by the need for larger light sources, such as gas lights with multiple jets, which required a longer focal length for a given beam-width, hence a larger lens to collect a given fraction of the generated light. The first hyper-radial lens was built for

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2816-412: Is the name that appears on money, in treaties, and in legal cases to which the nation is a party. The terms "Government of the United States of America" or "United States Government" are often used in official documents to represent the federal government as distinct from the states collectively. In casual conversation or writing, the term "Federal Government" is often used, and the term "U.S. Government"

2944-447: Is unknown. Much to Fresnel's embarrassment, one of the assembled commissioners, Jacques Charles , recalled Buffon's suggestion. However, whereas Buffon's version was biconvex and in one piece, Fresnel's was plano-convex and made of multiple prisms for easier construction. With an official budget of 500 francs, Fresnel approached three manufacturers. The third, François Soleil, found a way to remove defects by reheating and remolding

3072-414: The École Polytechnique , in order to save his remaining time and energy for his lighthouse work. In the same year he designed the first fixed lens—for spreading light evenly around the horizon while minimizing waste above or below. Ideally the curved refracting surfaces would be segments of toroids about a common vertical axis, so that the dioptric panel would look like a cylindrical drum. If this

3200-478: The 1 to 5 mm ( 1 ⁄ 32 to 3 ⁄ 16  in) range. Most modern Fresnel lenses consist only of refractive elements. Lighthouse lenses, however, tend to include both refracting and reflecting elements, the latter being outside the metal rings seen in the photographs. While the inner elements are sections of refractive lenses, the outer elements are reflecting prisms, each of which performs two refractions and one total internal reflection , avoiding

3328-513: The Isle of May , Scotland, on 22 September 1836. The first large catadioptric lenses were made in 1842 for the lighthouses at Gravelines and Île Vierge , France; these were fixed third-order lenses whose catadioptric rings (made in segments) were one metre in diameter. Stevenson's first-order Skerryvore lens, lit in 1844, was only partly catadioptric; it was similar to the Cordouan lens except that

3456-560: The Meta Quest Pro , have switched to a pancake lens design due to its smaller form factor and less chromatic aberration than Fresnel lenses. Multi-focal Fresnel lenses are also used as a part of retina identification cameras, where they provide multiple in- and out-of-focus images of a fixation target inside the camera. For virtually all users, at least one of the images will be in focus, thus allowing correct eye alignment. Canon and Nikon have used Fresnel lenses to reduce

3584-508: The Senate . The U.S. House of Representatives is made up of 435 voting members, each of whom represents a congressional district in a state from where they were elected. Apportionment of seats among the 50 states is determined by state populations, and it is updated after each decennial U.S. Census. Each member serves a two-year term. In order to be elected as a representative, an individual must be at least 25 years of age, must have been

3712-514: The Sinclair TV80 . They are also used in traffic lights . Fresnel lenses are used in left-hand-drive European lorries entering the UK and Republic of Ireland (and vice versa, right-hand-drive Irish and British trucks entering mainland Europe) to overcome the blind spots caused by the driver operating the lorry while sitting on the wrong side of the cab relative to the side of the road the car

3840-526: The Supreme Court , combat piracies and felonies , declare war , raise and support armies , provide and maintain a navy , make rules for the regulation of land and naval forces, provide for, arm and discipline the militia , exercise exclusive legislation in the District of Columbia , regulate interstate commerce , and to make laws necessary to properly execute powers. Over the two centuries since

3968-494: The U.S. Senate , all members of the U.S. House must be elected and cannot be appointed. In the case of a vacancy, the seat must be filled through a special election, as required under Article 1 of the U.S. Constitution. In contrast, the Senate is made up of two senators from each state, regardless of population. There are currently 100 senators (2 from each of the 50 states), who each serve six-year terms. Approximately one-third of

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4096-463: The U.S. Supreme Court . In the federal division of power, the federal government shares sovereignty with each of the 50 states in their respective territories. U.S. law recognizes Indigenous tribes as possessing sovereign powers , while being subject to federal jurisdiction. The full name of the republic is the "United States of America". No other name appears in the Constitution , and this

4224-532: The U.S. Tax Court , are specialized courts handling only certain kinds of cases, known as subject matter jurisdiction . The Bankruptcy Courts are supervised by the district courts, and, as such, are not considered part of the Article III judiciary. As such, their judges do not have lifetime tenure, nor are they Constitutionally exempt from diminution of their remuneration. The Tax Court is an Article I Court, not an Article III Court. The district courts are

4352-505: The United States District Courts , which are the general trial courts for federal law, and for certain controversies between litigants who are not deemed citizens of the same state, known as diversity jurisdiction . There are three levels of federal courts with general jurisdiction, which are courts that handle both criminal and civil suits between individuals. Other courts, such as the bankruptcy courts and

4480-914: The United States Postal Service (USPS), NASA , the Central Intelligence Agency (CIA), the Environmental Protection Agency (EPA), and the United States Agency for International Development (USAID). In addition, there are government-owned corporations , including the Federal Deposit Insurance Corporation and the National Railroad Passenger Corporation . The Judiciary, under Article III of

4608-713: The White House staff, the National Security Council , the Office of Management and Budget , the Council of Economic Advisers , the Council on Environmental Quality , the Office of the U.S. Trade Representative , the Office of National Drug Control Policy , and the Office of Science and Technology Policy . Outside of the EOP and the executive departments are a number of independent agencies . These include

4736-630: The head of government (the chief executive). The Constitution directs the president to " take care that the laws be faithfully executed " and requires the president to swear or affirm to "preserve, protect and defend the Constitution of the United States." Legal scholars William P. Marshall and Saikrishna B. Prakash write of the Clause: "the President may neither breach federal law nor order their subordinates to do so, for defiance cannot be considered faithful execution. The Constitution also incorporates

4864-488: The transverse wave hypothesis. Shortly after the Cordouan lens was lit, Fresnel started coughing up blood. In May 1824, Fresnel was promoted to Secretary of the Commission des Phares , becoming the first member of that body to draw a salary, albeit in the concurrent role of Engineer-in-Chief. Late that year, being increasingly ill, he curtailed his fundamental research and resigned his seasonal job as an examiner at

4992-646: The American coasts. During that time, congressional appointee, Lt. Jenkins of the United States Coast Survey conducted interviews with pilots and mariners, engaged in domestic and foreign research, and was involved in a number of hearings into existing navigational aids administration. On March 3, 1851, the United States Congress passed "An Act Making Appropriations for Light House, Light Boats, Buoys, &c." Section 8 of

5120-886: The Cabinet who are appointed by the president. These are the White House Chief of Staff, Administrator of the Environmental Protection Agency, Director of the Office of Management & Budget, United States Trade Representative, U.S. Ambassador to the United Nations, Chairman of the Council of Economic Advisers, and Administrator of the Small Business Administration. The heads of the 15 departments are chosen by

5248-576: The Commission that Fresnel was asked for a full eight-panel version. This model, completed a year later in spite of insufficient funding, had panels 76   cm square. In a public spectacle on the evening of 13 April 1821, it was demonstrated by comparison with the most recent reflectors, which it suddenly rendered obsolete. Soon after this demonstration, Fresnel published the idea that light, including apparently unpolarized light, consists exclusively of transverse waves , and went on to consider

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5376-569: The Constitution, explains and applies the laws. This branch does this by hearing and eventually making decisions on various legal cases. Article III section I of the Constitution establishes the Supreme Court of the United States and authorizes the United States Congress to establish inferior courts as their need shall arise. Section I also establishes a lifetime tenure for all federal judges and states that their compensation may not be diminished during their time in office. Article II section II establishes that all federal judges are to be appointed by

5504-593: The English bars on dispensing or suspending the law, with some supposing that the Clause itself prohibits both." Many presidential actions are undertaken via executive orders , presidential proclamations , and presidential memoranda . The president is the commander-in-chief of the armed forces . Under the Reception Clause , the president is empowered to "receive Ambassadors and other public Ministers";

5632-577: The House plus its two senators). The District of Columbia has a number of electoral votes "equal to the whole number of Senators and Representatives in Congress to which the District would be entitled if it were a State, but in no event more than the least populous State". A President may also be seated by succession . As originally drafted, there was no limit to the time a President could serve, however

5760-598: The Lighthouse Service was merged into the United States Coast Guard in 1939. By 1847, the United States Congress became serious about reforming the Lighthouse Establishment which had been in existence since 1791 and in response to a number of complaints, the U.S. Congress removed the responsibility for the construction of six new light stations from the U.S. Treasury Department's Fifth Auditor ( Stephen Pleasonton ), and transferred it to

5888-837: The President alone, in the Courts of Law, or in the Heads of Departments." These appointments delegate "by legal authority a portion of the sovereign powers of the federal government." The Constitution grants the president the "Power to grant Reprieves and Pardons for Offences against the United States , except in Cases of Impeachment"; this clemency power includes the power to issue absolute or conditional pardons, and to issue commute sentences , to remit fines, and to issue general amnesties . The presidential clemency power extends only to federal crimes, and not to state crimes. The president has informal powers beyond their formal powers. For example,

6016-464: The Rogers mirror of 60 years earlier, except that it subtended a whole hemisphere). Light radiated into the forward hemisphere but missing the bull's-eye lens was deflected by the paraboloid into a parallel beam surrounding the bull's-eye lens, while light radiated into the backward hemisphere was reflected back through the lamp by the spherical reflector (as in Rogers' arrangement), to be collected by

6144-439: The Senate stands for election every two years. If a vacancy occurs, the state governor appoints a replacement to complete the term or to hold the office until a special election can take place. The House and Senate each have particular exclusive powers. For example, the Senate must approve (give " advice and consent " to) many important presidential appointments, including cabinet officers, federal judges (including nominees to

6272-467: The Stevensons in 1885 by F. Barbier & Cie of France, and tested at South Foreland Lighthouse with various light sources. Chance Brothers (Hopkinson's employers) then began constructing hyper-radials, installing their first at Bishop Rock Lighthouse in 1887. In the same year, Barbier installed a hyper-radial at Tory Island . But only about 30 hyper-radials went into service before

6400-479: The Supreme Court), department secretaries (heads of federal executive branch departments), U.S. military and naval officers, and ambassadors to foreign countries. All legislative bills for raising revenue must originate in the House of Representatives. The approval of both chambers is required to pass all legislation, which then may only become law by being signed by the president (or, if the president vetoes

6528-493: The Twenty-second Amendment, ratified in 1951, originally limits any president to serving two four-year terms (8 years); the amendment specifically "caps the service of a president at 10 years" by providing that "if a person succeeds to the office of president without election and serves less than two years, he may run for two full terms; otherwise, a person succeeding to office of president can serve no more than

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6656-535: The U.S. Coast Survey, and Joseph Henry , Secretary of the Smithsonian Institution ; and Lt. Thornton Jenkins, U.S. Navy, who acted as secretary. These men attracted others of similar quality to lighthouse duty, both on the board and in district offices. The country was organized into 12 lighthouse districts, each having an inspector (a naval officer) who was charged with building the lighthouses and seeing that they remained in good condition and that

6784-493: The United States [REDACTED] [REDACTED] The federal government of the United States ( U.S. federal government or U.S. government ) is the common government of the United States , a federal republic located primarily in North America , comprising 50 states , five major self-governing territories , several island possessions , and the federal district (national capital) of Washington, D.C. , where

6912-464: The United States by the 1870s. In 1858 the company produced "a very small number of pressed flint-glass sixth-order lenses" for use in lighthouses—the first Fresnel lighthouse lenses made in America. By the 1950s, the substitution of plastic for glass made it economic to use Fresnel lenses as condensers in overhead projectors. The Fresnel lens reduces the amount of material required compared to

7040-525: The United States was formed, many disputes have arisen over the limits on the powers of the federal government. These disputes have often been the subject of lawsuits that have ultimately been decided by the United States Supreme Court . Congressional oversight is intended to prevent waste and fraud, protect civil liberties and individual rights, ensure executive compliance with the law, gather information for making laws and educating

7168-453: The act stated: The Secretary of the Treasury is authorized and required to cause a board to be convened at as early a day as may be practical after the passage of that act to be comprised of two officers of the Navy of high rank, two officers of Engineers of the Army, and such civil officers of scientific attainments as may be under the orders or at the disposition of the Treasury Department, and

7296-557: The actors and the camera, distorting the scale and composition of the scene to humorous effect. The Pixar movie Wall-E features a Fresnel lens in the scenes where the protagonist watches the musical Hello, Dolly! magnified on an iPod . Virtual reality headsets, such as the Meta Quest 2 and the HTC Vive Pro use Fresnel lenses, as they allow a thinner and lighter form factor than regular lenses. Newer devices, such as

7424-458: The bill, both houses of Congress then re-pass the bill, but by a two-thirds majority of each chamber, in which case the bill becomes law without the president's signature). The powers of Congress are limited to those enumerated in the Constitution; all other powers are reserved to the states and the people. The Constitution also includes the Necessary and Proper Clause , which grants Congress

7552-402: The case from state court to federal court. The United States Courts of Appeals are appellate courts that hear appeals of cases decided by the district courts, and some direct appeals from administrative agencies, and some interlocutory appeals. The U.S. Supreme Court hears appeals from the decisions of the courts of appeals or state supreme courts, and in addition has original jurisdiction over

7680-405: The center. The result was an all-glass holophote, with no losses from metallic reflections. James Timmins Chance modified Thomas Stevenson's all-glass holophotal design by arranging the double-reflecting prisms about a vertical axis. The prototype was shown at the 1862 International Exhibition in London. Later, to ease manufacturing, Chance divided the prisms into segments, and arranged them in

7808-404: The chambers to consider urgent matters. The vice president is the second-highest official in rank of the federal government. The vice president's duties and powers are established in the legislative branch of the federal government under Article 1, Section 3, Clauses 4 and 5 as the president of the Senate ; this means that they are the designated presiding officer of the Senate. In that capacity,

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7936-512: The completion of Augustin Fresnel's original Carte des Phares . Thomas Stevenson (younger brother of Alan) went a step beyond Fresnel with his "holophotal" lens, which focused the light radiated by the lamp in nearly all directions, forward or backward, into a single beam. The first version, described in 1849, consisted of a standard Fresnel bull's-eye lens, a paraboloidal reflector, and a rear hemispherical reflector (functionally equivalent to

8064-544: The consent of two-thirds of the Senate. Article II's Appointments Clause provides that the president "shall nominate, and by and with the Advice and Consent of the Senate, shall appoint Ambassadors, other public Ministers and Consuls, Judges of the supreme Court, and all other Officers of the United States " while providing that "Congress may by Law vest the Appointment of such inferior Officers, as they think proper, in

8192-668: The construction of the first lighthouses on the west coast. By the time of the Civil War, all lighthouses had Fresnel lenses. Previously, under the Establishment, the local collectors of customs were in charge of the lighthouses and other aids to navigation. In time, all duties regarding aids to navigation were taken from them. The Board demanded that only those who could read were to be appointed as keepers in order that they be able to read their written instructions. These instructions were detailed and covered everything possible about

8320-505: The control of Stephen Pleasonton . The quasi-military board first met on April 28, 1851, and with its establishment, the administration of lighthouses and other aids to navigation would take their largest leap toward modernization since the inception of federal government control. In 1910, the Lighthouse Board was disestablished in favor of a more civilian Lighthouse Service , under the Department of Commerce and Labor ; later

8448-631: The curved surfaces are replaced with flat surfaces, with a different angle in each section. Such a lens can be regarded as an array of prisms arranged in a circular fashion with steeper prisms on the edges and a flat or slightly convex center. In the first (and largest) Fresnel lenses, each section was actually a separate prism. 'Single-piece' Fresnel lenses were later produced, being used for automobile headlamps, brake, parking, and turn signal lenses, and so on. In modern times, computer-controlled milling equipment (CNC) or 3-D printers might be used to manufacture more complex lenses. Fresnel lens design allows

8576-620: The date as 1773 or 1788 ), the Marquis de Condorcet suggested that it would be easier to make the annular sections separately and assemble them on a frame; but even that was impractical at the time. These designs were intended not for lighthouses, but for burning glasses . David Brewster , however, proposed a system similar to Condorcet's in 1811, and by 1820 was advocating its use in British lighthouses. The French Commission des Phares  [ FR ] (Commission of Lighthouses)

8704-549: The development of more compact bright lamps rendered such large optics unnecessary (see Hyperradiant Fresnel lens ). Production of one-piece stepped dioptric lenses—roughly as envisaged by Buffon—became feasible in 1852, when John L. Gilliland of the Brooklyn Flint-Glass Company patented a method of making lenses from pressed and molded glass. The company made small bull's-eye lenses for use on railroads, steamboats, and docks; such lenses were common in

8832-572: The economy. In addition, each house may name special, or select, committees to study specific problems. Today, much of the congressional workload is borne by the subcommittees, of which there are around 150. The Constitution grants numerous powers to Congress. Enumerated in Article I, Section 8, these include the powers to levy and collect taxes ; to coin money and regulate its value; provide for punishment for counterfeiting; establish post offices and roads, issue patents, create federal courts inferior to

8960-418: The executive branch when becoming president upon the death, resignation, or removal of the president, which has happened nine times in U.S. history. Lastly, in the case of a Twenty-fifth Amendment succession event, the vice president would become acting president, assuming all of the powers and duties of president, except being designated as president. Accordingly, by circumstances, the Constitution designates

9088-572: The field of popular entertainment. The British rock artist Peter Gabriel made use of them in his early solo live performances to magnify the size of his head, in contrast to the rest of his body, for dramatic and comic effect. In the Terry Gilliam film Brazil , plastic Fresnel screens appear ostensibly as magnifiers for the small CRT monitors used throughout the offices of the Ministry of Information. However, they occasionally appear between

9216-478: The forward components. The first unit was installed at North Harbour, Peterhead , in August 1849. Stevenson called this version a "catadioptric holophote", although each of its elements was either purely reflective or purely refractive. In the second version of the holophote concept, the bull's-eye lens and paraboloidal reflector were replaced by a catadioptric Fresnel lens—as conceived by Fresnel, but expanded to cover

9344-462: The glass. Arago assisted Fresnel with the design of a modified Argand lamp with concentric wicks (a concept that Fresnel attributed to Count Rumford ), and accidentally discovered that fish glue was heat-resistant, making it suitable for use in the lens. The prototype, finished in March 1820, had a square lens panel 55   cm on a side, containing 97 polygonal (not annular) prisms—and so impressed

9472-433: The implications for double refraction and partial reflection. Fresnel acknowledged the British lenses and Buffon's invention in a memoir read on 29 July 1822 and printed in the same year. The date of that memoir may be the source of the claim that Fresnel's lighthouse advocacy began two years later than Brewster's; but the text makes it clear that Fresnel's involvement began no later than 1819. Fresnel's next lens

9600-445: The incident light. Another report by Fresnel, dated 29 August 1819 (Fresnel, 1866–70, vol. 3, pp. 15–21), concerns tests on reflectors, and does not mention stepped lenses except in an unrelated sketch on the last page of the manuscript. The minutes of the meetings of the Commission go back only to 1824, when Fresnel himself took over as Secretary. Thus the exact date on which Fresnel formally recommended lentilles à échelons

9728-456: The lamp and into the lens. Further samples were installed at Howth Baily , North Foreland , and at least four other locations by 1804. But much of the light was wasted by absorption in the glass. In 1748, Georges-Louis Leclerc, Comte de Buffon was the first to replace a convex lens with a series of concentric annular prisms, ground as steps in a single piece of glass, to reduce weight and absorption. In 1790 (although secondary sources give

9856-486: The law and creating precedent for future law and decisions. The United States Constitution does not specifically mention the power of judicial review , which is the power to declare a law unconstitutional. There have been instances in the past where such declarations have been ignored by the other two branches. Below the U.S. Supreme Court are the United States Courts of Appeals , and below them in turn are

9984-502: The lens can hold a colored plastic film ( gel ) to tint the light or wire screens or frosted plastic to diffuse it. The Fresnel lens is useful in the making of motion pictures not only because of its ability to focus the beam brighter than a typical lens, but also because the light is a relatively consistent intensity across the entire width of the beam of light. Aircraft carriers and naval air stations typically use Fresnel lenses in their optical landing systems . The "meatball" light aids

10112-473: The lens was first proposed by Georges-Louis Leclerc, Comte de Buffon , and independently reinvented by the French physicist Augustin-Jean Fresnel (1788–1827) for use in lighthouses . The catadioptric (combining refraction and reflection) form of the lens, entirely invented by Fresnel, has outer prismatic elements that use total internal reflection as well as refraction to capture more oblique light from

10240-406: The lens was in operation. After a few years the inspectors became overloaded with work and an engineer (an army officer) was appointed to each district to tend to the construction and maintenance of lighthouses. The Lighthouse Board moved quickly in applying new technology, particularly in purchasing and installing new Fresnel lenses and constructing screw-pile lighthouses . The Board also oversaw

10368-468: The light loss that occurs in reflection from a silvered mirror. Fresnel designed six sizes of lighthouse lenses, divided into four orders based on their size and focal length. The 3rd and 4th orders were sub-divided into "large" and "small". In modern use, the orders are classified as first through sixth order. An intermediate size between third and fourth order was added later, as well as sizes above first order and below sixth. A first-order lens has

10496-475: The light source and add it to the beam, making it visible at greater distances. The design allows the construction of lenses of large aperture and short focal length without the mass and volume of material that would be required by a lens of conventional design. A Fresnel lens can be made much thinner than a comparable conventional lens, in some cases taking the form of a flat sheet. Because of its use in lighthouses, it has been called "the invention that saved

10624-460: The light source. The light path through these elements can include an internal reflection , rather than the simple refraction in the planar Fresnel element. These lenses conferred many practical benefits upon the designers, builders, and users of lighthouses and their illumination. Among other things, smaller lenses could fit into more compact spaces. Greater light transmission over longer distances, and varied patterns, made it possible to triangulate

10752-555: The lower slats were replaced by French-made catadioptric prisms, while mirrors were retained at the top. The first fully catadioptric first-order lens, installed at Pointe d'Ailly in 1852, also gave eight rotating beams plus a fixed light at the bottom; but its top section had eight catadioptric panels focusing the light about 4 degrees ahead of the main beams, in order to lengthen the flashes. The first fully catadioptric lens with purely revolving beams—also of first order—was installed at Saint-Clément-des-Baleines in 1854, and marked

10880-402: The main beam, increasing the duration of the flash. Below the main panels were 128 small mirrors arranged in four rings, stacked like the slats of a louver or Venetian blind . Each ring, shaped like a frustum of a cone , reflected the light to the horizon, giving a fainter steady light between the flashes. The official test, conducted on the unfinished Arc de Triomphe on 20 August 1822,

11008-503: The majority of the federal government is based. The U.S. federal government is composed of three distinct branches: legislative , executive , and judicial , whose powers are vested by the U.S. Constitution in the Congress , the president , and the federal courts , respectively. The powers and duties of these branches are further defined by acts of Congress, including the creation of executive departments and courts subordinate to

11136-428: The middle of the 20th centuries; most lighthouses have now retired glass Fresnel lenses from service and replaced them with much less expensive and more durable aerobeacons , which themselves often contain plastic Fresnel lenses. Lighthouse Fresnel lens systems typically include extra annular prismatic elements, arrayed in faceted domes above and below the central planar Fresnel, in order to catch all light emitted from

11264-477: The nation's highest judiciary authority, the Supreme Court (as well as to lower federal courts), but those nominees must be approved by Congress. The Supreme Court, in turn, can invalidate unconstitutional laws passed by the Congress. The United States Congress , under Article I of the Constitution, is the legislative branch of the federal government. It is bicameral , comprising the House of Representatives and

11392-467: The nation's waterways. Iron buoys were introduced to replace the more expensive copper-clad wooden buoys. The Lighthouse Board also began printing changes made in aids to navigation as a Notice to Mariners . Several advances in the technology of fog signals were made during the 1850s. In 1851, an experimental air fog whistle and reed horn was installed at Beavertail Lighthouse at the entrance to Narragansett Bay , Rhode Island . At first this sound signal

11520-476: The need for filters by inventing the "group-flashing" lens, in which the dioptric and/or the catadioptric panels were split so as to give multiple flashes—allowing lighthouses to be identified not only by frequency of flashes, but also by multiplicity of flashes. Double-flashing lenses were installed at Tampico (Mexico) and Little Basses (Sri Lanka) in 1875, and a triple-flashing lens at Casquets Lighthouse ( Channel Islands ) in 1876. The example shown (right)

11648-519: The next five decades several advances in lighthouse construction technology took place including the development of the exposed screwpile lighthouses, exoskeleton lighthouses, waveswept interlocking stone lighthouses, iron caisson lighthouses, and breakwater lighthouses. In the 1850s the Board prescribed color schemes for the buoys, as well as range lights and day markers; and the buoy system was standardized. Classification systems were also developed to mark

11776-423: The number of segments increases, the two types of lens become more similar to each other. In the abstract case of an infinite number of segments, the difference between curved and flat segments disappears. Imaging lenses can be classified as: Non-imaging lenses can be classified as: High-quality glass Fresnel lenses were used in lighthouses, where they were considered state of the art in the late 19th and through

11904-702: The office of vice president. Article II, Section 2 of the Constitution sets forth the creation of a presidential Cabinet. The role of the Cabinet is to advise the president and carry out the programs and laws of the federal government. The Cabinet is composed of the vice president and the leaders of 15 executive departments. Those executive departments are the Departments of State, Treasury, Defense, Justice, Interior, Agriculture, Commerce, Labor, Health and Human Services, Housing and Urban Development, Transportation, Energy, Education, Veterans Affairs, and Homeland Security. Additionally, there are seven other members of

12032-403: The official. Then, a trial is held in the Senate to decide whether the official should be removed from office. As of 2023 , three presidents have been impeached: Andrew Johnson , Bill Clinton , and Donald Trump (twice). None of the three were removed from office following trial in the Senate. Article I, Section 2, paragraph 2 of the U.S. Constitution gives each chamber the power to "determine

12160-585: The operation of lighthouses, leaving little discretion to the keeper. The Board struggled to eliminate politics from its activities, and slowly the organization became a professional career agency, helped greatly by the Civil Service Reform Acts of 1871 and 1883. Keepers became civil service employees in 1896. Most important, the Board was constantly mindful of advancing technology and took advantage of new types of lighthouses, buoys, or fog signals, as well as improvement in lighthouse optics. Over

12288-412: The pilot in maintaining proper glide slope for the landing. In the center are amber and red lights composed of Fresnel lenses. Although the lights are always on, the angle of the lens from the pilot's point of view determines the color and position of the visible light. If the lights appear above the green horizontal bar, the pilot is too high. If it is below, the pilot is too low, and if the lights are red,

12416-399: The pilot is very low. Fresnel lenses are also commonly used in searchlights , spotlights , and flashlights . Fresnel lenses are used as simple hand-held magnifiers . They are also used to correct several visual disorders, including ocular-motility disorders such as strabismus . Fresnel lenses have been used to increase the visual size of CRT displays in pocket televisions , notably

12544-488: The plaintiffs and the government of another state was the defendant. It did not disturb federal jurisdiction in cases in which a state government is a plaintiff and a citizen of another state the defendant. The power of the federal courts extends both to civil actions for damages and other redress, and to criminal cases arising under federal law. The interplay of the Supremacy Clause and Article III has resulted in

12672-543: The power to "make all laws which shall be necessary and proper for carrying into execution the foregoing powers". Members of the House and Senate are elected by first-past-the-post voting in every state except Louisiana and Georgia , which have runoffs , and Maine and Alaska , which use ranked-choice voting . Congress has the power to remove the president, federal judges, and other federal officers from office. The House of Representatives and Senate have separate roles in this process. The House must first vote to impeach

12800-497: The power to adjourn Congress whenever the House and Senate cannot agree when to adjourn; no president has ever used this power. The president also has the constitutional power to, "on extraordinary Occasions, convene both Houses, or either of them"; this power has been used "to consider nominations, war, and emergency legislation." This Section invests the President with the discretion to convene Congress on "extraordinary occasions"; this special session power that has been used to call

12928-558: The power to re-organize or even abolish federal courts lower than the Supreme Court. The U.S. Supreme Court decides cases and controversies , which include matters pertaining to the federal government, disputes between states, and interpretation of the United States Constitution, and, in general, can declare legislation or executive action made at any level of the government as unconstitutional , nullifying

13056-502: The president and approved with the "advice and consent" of the U.S. Senate. Once confirmed, these "Cabinet secretaries" serve at the pleasure of the president. In addition to the executive departments, a number of staff organizations are grouped into the Executive Office of the President (EOP), which was created in 1939 by President Franklin D. Roosevelt. The EOP is overseen by the White House Chief of Staff. The EOP includes

13184-485: The president and confirmed by the United States Senate. The Judiciary Act of 1789 subdivided the nation jurisdictionally into judicial districts and created federal courts for each district. The three tiered structure of this act established the basic structure of the national judiciary: the Supreme Court, 13 courts of appeals, 94 district courts, and two courts of special jurisdiction. Congress retains

13312-543: The president has broad authority to conduct foreign relations, is generally considered to have the sole power of diplomatic recognition , and is the United States' chief diplomat, although the Congress also has an important role in legislating on foreign affairs, and can, for example, "institute a trade embargo, declare war upon a foreign government that the President had recognized, or decline to appropriate funds for an embassy in that country." The president may also negotiate and sign treaties, but ratifying treaties requires

13440-474: The president has major agenda-setting powers to influence lawmaking and policymaking, and typically has a major role as the leader of their political party . The president and vice president are normally elected as running mates by the Electoral College ; each state has a number of electoral votes equal to the size of its Congressional delegation ( i.e. , its number of Representatives in

13568-525: The president's signature, "unless the Congress by their Adjournment prevent its Return in which Case it shall not be a Law" (called a pocket veto ). A presidential veto may be overridden by a two-thirds vote in both houses of Congress; this occurs relatively infrequently. The president may be impeached by a majority in the House and removed from office by a two-thirds majority in the Senate for " treason , bribery , or other high crimes and misdemeanors ". The president may not dissolve Congress , but has

13696-501: The public, and evaluate executive performance. It applies to cabinet departments, executive agencies, regulatory commissions, and the presidency. Congress's oversight function takes many forms: The executive branch is established in Article Two of the United States Constitution , which vests executive power in the president of the United States . The president is both the head of state (performing ceremonial functions) and

13824-477: The rules of its proceedings". From this provision were created congressional committees , which do the work of drafting legislation and conducting congressional investigations into national matters. The 118th Congress (2023–2025) has 20 standing committees in the House and 19 in the Senate, plus 4 joint permanent committees with members from both houses overseeing the Library of Congress , printing, taxation, and

13952-479: The same way as the president or other officials of the federal government. U.S. judges are appointed by the president, subject to confirmation by the Senate. Another Constitutional provision prohibits Congress from reducing the pay of any present Article III judge. However, Congress is able to set a lower salary for all future judges who take office after such a pay reduction is passed by Congress. Fresnel lens The simpler dioptric (purely refractive ) form of

14080-415: The size of telephoto lenses. Photographic lenses that include Fresnel elements can be much shorter than corresponding conventional lens design. Nikon calls the technology Phase Fresnel . The Polaroid SX-70 camera used a Fresnel reflector as part of its viewing system. View and large format cameras can utilize a Fresnel lens in conjunction with the ground glass , to increase the perceived brightness of

14208-519: The statue, under the Lighthouse Board's care from 1886 to 1902, marks the beginning of the "modern age" in lighthouse illumination. In 1900, the Lighthouse Board began converting lighthouses to electric service; however, because of the lack of direct access to power lines, the conversion came about slowly. This article contains information created by the US Federal Government and is in the public domain . Federal Government of

14336-548: The supervision of the United States Army 's, long-time construction agency, the Corps of Engineers . When it became clear that this would not alleviate the underlying problems in the Lighthouse Establishment, Congress then felt compelled to deal the final blow to Pleasonton's administration. The ensuing congressional investigation took more than four years to effect a change in the administration of navigation aids along

14464-751: The test of the Cordouan lens in Paris, a committee of the Academy of Sciences reported on Fresnel's memoir and supplements on double refraction—which, although less well known to modern readers than his earlier work on diffraction, struck a more decisive blow for the wave theory of light. Between the test and the reassembly at Cordouan, Fresnel submitted his papers on photoelasticity (16 September 1822), elliptical and circular polarization and optical rotation (9 December), and partial reflection and total internal reflection (7 January 1823), essentially completing his reconstruction of physical optics on

14592-534: The third surface. The result was the lighthouse lens as we now know it. In 1826 he assembled a small model for use on the Canal Saint-Martin , but he did not live to see a full-sized version: he died on 14 July 1827, at the age of 39. The first stage of the development of lighthouse lenses after the death of Augustin Fresnel consisted in the implementation of his designs. This was driven in part by his younger brother Léonor—who, like Augustin,

14720-529: The trial courts wherein cases that are considered under the Judicial Code (Title 28, United States Code) consistent with the jurisdictional precepts of federal question jurisdiction , diversity jurisdiction, and pendent jurisdiction can be filed and decided. The district courts can also hear cases under removal jurisdiction , wherein a case brought in a state court meets the requirements for diversity jurisdiction, and one party litigant chooses to "remove"

14848-518: The vice president as routinely in the legislative branch, or succeeding to the executive branch as president, or possibly being in both as acting president pursuant to the Twenty-fifth Amendment . Because of circumstances, the overlapping nature of the duties and powers attributed to the office, the title of the office and other matters, such has generated a spirited scholarly dispute regarding attaching an exclusive branch designation to

14976-522: The vice president has the authority ( ex officio , for they are not an elected member of the Senate) to cast a tie-breaking vote . Pursuant to the Twelfth Amendment , the vice president presides over the joint session of Congress when it convenes to count the vote of the Electoral College . As first in the U.S. presidential line of succession , the vice president's duties and powers move to

15104-410: The whole forward hemisphere. The third version, which Stevenson confusingly called a "dioptric holophote", was more innovative: it retained the catadioptric Fresnel lens for the front hemisphere, but replaced the rear hemispherical reflector with a hemispherical array of annular prisms, each of which used two total internal reflections to turn light diverging from the center of the hemisphere back toward

15232-536: Was "temporarily" seconded to the commission on the recommendation of François Arago (a member since 1813), to review possible improvements in lighthouse illumination. By the end of August 1819, unaware of the Buffon-Condorcet-Brewster proposal, Fresnel made his first presentation to the commission, recommending what he called lentilles à échelons ('lenses by steps') to replace the reflectors then in use, which reflected only about half of

15360-407: Was a rotating apparatus with eight "bull's-eye" panels, made in annular arcs by Saint-Gobain , giving eight rotating beams—to be seen by mariners as a periodic flash. Above and behind each main panel was a smaller, sloping bull's-eye panel of trapezoidal outline with trapezoidal elements. This refracted the light to a sloping plane mirror, which then reflected it horizontally, 7 degrees ahead of

15488-488: Was an ordinary locomotive whistle, enlarged and modified and blown by steam from a high-pressure tubular boiler. The second was a reed-trumpet, and in 1866 the third variation, a siren-trumpet. Although the fog bell signal was still used for warning vessels over short distances, other fog signals started to supersede the smaller bell signal. Bells were also used on buoys; later whistling buoys were invented by J. M. Courtenay and were first in use in 1876. The first gas-lighted buoy

15616-593: Was decided to build and outfit the Makapuu Point Light in Hawaii. Rather than order a new lens, the huge optic construction, 3.7 metres (12 ft) tall and with over a thousand prisms, was used there. There are two main types of Fresnel lens: imaging and non-imaging . Imaging Fresnel lenses use segments with curved cross-sections and produce sharp images, while non-imaging lenses have segments with flat cross-sections, and do not produce sharp images. As

15744-468: Was established by Napoleon in 1811, and placed under the authority of French physicist Augustin-Jean Fresnel 's employer, the Corps of Bridges and Roads. As the members of the commission were otherwise occupied, it achieved little in its early years. However, on 21 June 1819—three months after winning the physics Grand Prix of the Academy of Sciences for his celebrated memoir on diffraction —Fresnel

15872-456: Was installed in 1882. The gong buoy was invented in 1923. In 1876, under the management of Chief Clerk Arnold B. Johnson , the Lighthouse Board began to circulate and maintain traveling lighthouse libraries . These libraries would continue to be in service until the 1930s. In 1886, a new technology was tested in the illumination of the Statue of Liberty —electricity. The electrical lighting of

16000-458: Was powered by a horse-operated treadmill and later by an internal combustion steam engine. Around 1851, mechanically rung fog bells were introduced. The striking mechanism was governed by a weight attached to a flywheel, and later internally run by clockworks. The strokes of the fog signals were timed deliberately to afford each signal a unique sound characteristic. The bell signal was gradually replaced by three variations of that instrument. The first

16128-447: Was supplemented by reflecting ( catoptric ) rings above and below the refracting (dioptric) parts, the entire apparatus would look like a beehive. The second Fresnel lens to enter service was indeed a fixed lens, of third order, installed at Dunkirk by 1 February 1825. However, due to the difficulty of fabricating large toroidal prisms, this apparatus had a 16-sided polygonal plan. In 1825 Fresnel extended his fixed-lens design by adding

16256-595: Was trained as a civil engineer but, unlike Augustin, had a strong aptitude for management. Léonor entered the service of the Lighthouse Commission in 1825, and went on to succeed Augustin as Secretary. The first fixed lens to be constructed with toroidal prisms was a first-order apparatus designed by the Scottish engineer Alan Stevenson under the guidance of Léonor Fresnel, and fabricated by Isaac Cookson & Co. using French glass; it entered service at

16384-511: Was witnessed by the Commission—and by Louis XVIII and his entourage—from 32 kilometres (20 mi) away. The apparatus was stored at Bordeaux for the winter, and then reassembled at Cordouan Lighthouse under Fresnel's supervision—in part by Fresnel's own hands. On 25 July 1823, the world's first lighthouse Fresnel lens was lit. As expected, the light was visible to the horizon, more than 32 kilometres (20 mi) out. The day before

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