The Wedgwood scale is an obsolete temperature scale, used to measure temperatures above the boiling point of mercury of 356 °C. The scale and associated measurement technique were proposed by the English potter Josiah Wedgwood in the 18th century; the measurement was based on the shrinking of clay when heated above red heat, the shrinking was evaluated by comparing heated and unheated clay cylinders. The scale started at 1,077.5 °F being 0° Wedgwood and had 240 steps of 130 °F. Both the origin and the step were found inaccurate; the boiling point of mercury limits the mercury-in-glass thermometer to temperatures below 356 °C, too low for many industrial applications such as pottery, glass making and metallurgy. To solve this problem, the English potter Josiah Wedgwood proposed, in the 18th century, a method to measure temperatures in his kilns, his method and temperature scale were widely adopted in science and technical applications. They were abandoned after the invention of accurate types of pyrometer, for example the pyrometer of John Frederic Daniell in 1830.
A 0.5-inch-diameter cylinder made from pipe clay was dried at the temperature of boiling water. This would prepare it for heating in the oven. During the annealing, sintering of fine particles resulted in contraction of clay. After cooling, the temperature was evaluated from the diameter difference before and after heating assuming that the contraction is linear with temperature. To facilitate the temperature calculation, Wedgwood built a device which would directly read the temperature. Two metal bars with scales on them were fixed one above another on a metal plate and inclined at a small angle; the spacing between the bars was 0.3 inches at the lower end. The scale was divided into 240 equidistant parts; the unheated piece of clay would fit the 0.5-inch gap giving the zero temperature reading. After annealing, the clay cylinder would shrink and fit somewhere in between the left and right ends of the bars, the temperature could be read from the scales on the bars; the origin on Wedgwood scale was set at the onset temperature of red heat, 1,077.5 °F.
The scale had 240 steps of 130 °F and extended up to 32,277 °F. Wedgwood tried to compare his scale with other scales by measuring the expansion of silver as a function of temperature, he determined the melting points of three metals, namely copper and gold. All these values are at least 2,500 °F too high. Louis-Bernard Guyton de Morveau used his pyrometer to evaluate the temperature scale of Wedgwood and came to the conclusion that the starting point should be lower, at 517 °F instead of 1,077.5 °F, that the steps should be nearly halved from 130 °F to no more than 62.5 °F. However after this revision the Wedgwood measurements overestimated the melting points of elements
Warden of the Mint
Warden of the Mint was a high-ranking position at the Royal Mint in England from 1216–1829. The warden was responsible for a variety of minting procedures and acted as the immediate representative of the current monarch inside the mint; the role of warden changed through history with the original task being the receiving and payment for bullion, while evolving into more of an administerial role. The office received a yearly emolument of £500 and up until 1685 wardens were given tenure meaning many wardens died while in office. Although technically subordinate to the Master of the Mint whose jobs was act as a contractor to the crown many wardens advanced on to become Master of the Mint with some wardens holding both offices at the same time; the most illustrious holder of the office of Warden of the Mint was Isaac Newton, warranted to this position on the recommendation of his friend, Chancellor of the Exchequer in 1698. In 1699 however, Newton undertook the office of Master of the Mint, far more lucrative, as well as more technically challenging.
After the death of the final warden Sir Walter James, 1st Baronet in 1829 the office was abolished having existed for 613 years. Münzwardein Master of the Mint Galileo Project Biography of Newton Royal Mint Biography of Newton Institute of Historical Research – Wardens of the Mint
Structural coloration is the production of colour by microscopically structured surfaces fine enough to interfere with visible light, sometimes in combination with pigments. For example, peacock tail feathers are pigmented brown, but their microscopic structure makes them reflect blue and green light, they are iridescent. Structural coloration was first observed by English scientists Robert Hooke and Isaac Newton, its principle – wave interference – explained by Thomas Young a century later. Young described iridescence as the result of interference between reflections from two or more surfaces of thin films, combined with refraction as light enters and leaves such films; the geometry determines that at certain angles, the light reflected from both surfaces interferes constructively, while at other angles, the light interferes destructively. Different colours therefore appear at different angles. In animals such as on the feathers of birds and the scales of butterflies, interference is created by a range of photonic mechanisms, including diffraction gratings, selective mirrors, photonic crystals, crystal fibres, matrices of nanochannels and proteins that can vary their configuration.
Some cuts of meat show structural coloration due to the exposure of the periodic arrangement of the muscular fibres. Many of these photonic mechanisms correspond to elaborate structures visible by electron microscopy. In the few plants that exploit structural coloration, brilliant colours are produced by structures within cells; the most brilliant blue coloration known in any living tissue is found in the marble berries of Pollia condensata, where a spiral structure of cellulose fibrils produces Bragg's law scattering of light. The bright gloss of buttercups is produced by thin-film reflection by the epidermis supplemented by yellow pigmentation, strong diffuse scattering by a layer of starch cells beneath. Structural coloration has potential for industrial and military application, with biomimetic surfaces that could provide brilliant colours, adaptive camouflage, efficient optical switches and low-reflectance glass. In his 1665 book Micrographia, Robert Hooke described the "fantastical" colours of the peacock's feathers: The parts of the Feathers of this glorious Bird appear, through the Microscope, no less gaudy do the whole Feathers.
… their upper sides seem to me to consist of a multitude of thin plated bodies, which are exceeding thin, lie close together, thereby, like mother of Pearl shells, do not onely reflect a brisk light, but tinge that light in a most curious manner. Now, that these colours are onely fantastical ones, that is, such as arise from the refractions of the light, I found by this, that water wetting these colour'd parts, destroy'd their colours, which seem'd to proceed from the alteration of the reflection and refraction. In his 1704 book Opticks, Isaac Newton described the mechanism of the colours other than the brown pigment of peacock tail feathers. Newton noted that The finely colour'd Feathers of some Birds, those of Peacocks Tails, do, in the same part of the Feather, appear of several Colours in several Positions of the Eye, after the same manner that thin Plates were found to do in the 7th and 19th Observations, therefore their Colours arise from the thinness of the transparent parts of the Feathers.
Thomas Young extended Newton's particle theory of light by showing that light could behave as a wave. He showed in 1803 that light could diffract from sharp edges or slits, creating interference patterns. In his 1892 book Animal Coloration, Frank Evers Beddard acknowledged the existence of structural colours: The colours of animals are due either to the presence of definite pigments in the skin, or … beneath the skin. Colours of the latter kind are spoken of as structural colours; the metallic lustre of the feathers of many birds, such as the humming birds, is due to the presence of excessively fine striae upon the surface of the feathers. But Beddard largely dismissed structural coloration, firstly as subservient to pigments: "in every case the colour needs for its display a background of dark pigment. Structural coloration is caused by interference effects rather than by pigments. Colours are produced when a material is scored with fine parallel lines, formed of one or more parallel thin layers, or otherwise composed of microstructures on the scale of the colour's wavelength.
Structural coloration is responsible for the blues and greens of the feathers of many birds, as well as many butterfly wings, beetle wing-cases and the gloss of buttercup petals. These are iridescent, as in peacock feathers and
The Newton disc is a well-known physics experiment with a rotating disc with segments in different colors appearing as white when it spins fast. This type of mix of light stimuli is called temporal optical mixing, a version of additive-averaging mixing; the concept that human visual perception cannot distinguish details of high-speed movements is popularly known as persistence of vision. The disc is named after Isaac Newton. Although he published a circular diagram with segments for the primary colors that he had discovered, it is uncertain whether he ever used a spinning disc to demonstrate the principles of light. Transparent variations for magic lantern projection have been produced. Around CE 165 Ptolemy described in his book Optics a rotating potter's wheel with different colors on it, he noted how the different colors of sectors mixed together into one color and how dots appeared as circles when the wheel was spinning fast. When lines are drawn across the axis of the disc they make the whole surface appear to be of a uniform color.
"The visual impression, created in the first revolution is invariably followed by repeated instances that subsequently produce an identical impression. This happens in the case of shooting stars, whose light seems distended on account of their speed of motion, all according to the amount of perceptible distance it passes along with the sensible impression that arises in the visual faculty."Porphyry wrote in his commentary on Ptolemy's Harmonics how the senses are not stable but confused and inaccurate. Certain intervals between repeated impressions are not detected. A white or black spot on a spinning cone appears as a circle of that color and a line on the top makes the whole surface appear in that color. "Because of the swiftness of the movement we receive the impression of the line on every part of the cone as the line moves."In the 11th century Ibn al-Haytam, familiar with Ptolemy's writings, described how colored lines on a spinning top could not be discerned as different colors but appeared as one new color composed of all of the colors of the lines.
He deducted. Al-Haytam noted that the top appeared motionless when spun quick "for none of its points remains fixed in the same spot for any perceptible time". On 6 February 1671/72 Isaac Newton wrote a paper about the experiments he had been conducting since 1666 with the refraction of light through glass prisms, he concluded that the different refracted rays of light - well parted from others - could not be changed by further refraction, nor by reflection or other means, except through mixture with other rays. He thus found the seven primary colors red, yellow, blue, "a violet-purple" and indigo; when mixing the coloured rays from a prism, he found that "the most surprising and wonderful composition was that of whiteness" requiring all the primary colors "mixed in a due proportion". In his book Opticks Newton described a device with prisms, a lens and a large moving comb with teeth causing alternating colors to be projected successively. "But if I so much accelerated the Motion, that the Colours by reason of their quick Succession could not be distinguished from one another, the Appearance of the single Colours ceased.
There was no red, no yellow, no green, no blue, nor purple to be seen any longer, but from a Confusion of them all there arose one uniform white Colour." Newton noted that the same principle is visible in the way a soapy froth displays colours when seen up close but appears as white from a small distance. Although a mix of powder pigments of the primary colors appeared grey, Newton demonstrated that it looked white when seen in bright sunlight from a small distance. After presenting his conclusions about dividing sunlight into primary colors and mixing them back together into white light, Newton presented a color circle to illustrate the relations between these colors. Many modern sources state that Isaac Newton himself used a spinning disc with colored sectors to demonstrate how white light was the compound of the primary colors. However, these do not reference any historical source. Benham's top "Newton's Disk Flash". TD Flash Zone. 2017
Method of Fluxions
Method of Fluxions is a book by Isaac Newton. The book was completed in 1671, published in 1736. Fluxion is Newton's term for a derivative, he developed the method at Woolsthorpe Manor during the closing of Cambridge during the Great Plague of London from 1665 to 1667, but did not choose to make his findings known. Gottfried Leibniz developed his form of calculus independently around 1673, 7 years after Newton had developed the basis for differential calculus, as seen in surviving documents like “the method of fluxions and fluents..." from 1666. Leibniz however published his discovery of differential calculus in 1684, nine years before Newton formally published his fluxion notation form of calculus in part during 1693; the calculus notation in use today is that of Leibniz, although Newton's dot notation for differentiation x ˙ for denoting derivatives with respect to time is still in current use throughout mechanics and circuit analysis. Newton's Method of Fluxions was formally published posthumously, but following Leibniz's publication of the calculus a bitter rivalry erupted between the two mathematicians over who had developed the calculus first and so Newton no longer hid his knowledge of fluxions.
For a period of time encompassing Newton's working life, the discipline of analysis was a subject of controversy in the mathematical community. Although analytic techniques provided solutions to long-standing problems, including problems of quadrature and the finding of tangents, the proofs of these solutions were not known to be reducible to the synthetic rules of Euclidean geometry. Instead, analysts were forced to invoke infinitesimal, or "infinitely small", quantities to justify their algebraic manipulations; some of Newton's mathematical contemporaries, such as Isaac Barrow, were skeptical of such techniques, which had no clear geometric interpretation. Although in his early work Newton used infinitesimals in his derivations without justifying them, he developed something akin to the modern definition of limits in order to justify his work. Method of Fluxions at the Internet Archive
Newton's cradle is a device that demonstrates conservation of momentum and energy using a series of swinging spheres. When one sphere at the end is lifted and released, it strikes the stationary spheres, transmitting a force through the stationary spheres that pushes the last sphere upward; the last sphere swings back and strikes the still nearly stationary spheres, repeating the effect in the opposite direction. The device is named after 17th-century English scientist Sir Isaac Newton, it is known as Newton's Balls or Executive Ball Clicker. A typical Newton's cradle consists of a series of identically sized metal balls suspended in a metal frame so that they are just touching each other at rest; each ball is attached to the frame by two wires of equal length angled away from each other. This restricts the pendulums' movements to the same plane; when one of the end balls is pulled sideways, the attached string makes it follow an upward arc. When it is let go, it comes to nearly a dead stop; the ball on the opposite side acquires most of the velocity of the first ball and swings in an arc as high as the release height of the first ball.
This shows that the last ball receives most of the momentum of the first ball. The impact produces a compression wave. Any efficiently elastic material such as steel does this, as long as the kinetic energy is temporarily stored as potential energy in the compression of the material rather than being lost as heat. There are slight movements in all the balls after the initial strike but the last ball receives most of the initial energy from the drop of the first ball; when two balls are dropped, the two balls on the opposite side swing out. Some say that this behavior demonstrates the conservation of momentum and kinetic energy in elastic collisions. However, if the colliding balls behave as described above with the same mass possessing the same velocity before and after the collisions any function of mass and velocity is conserved in such an event. Newton's cradle can be modeled with simple physics and minor errors if you incorrectly assume the balls always collide in pairs. If one ball strikes four stationary balls that are touching, the simplification can't explain the resulting movements in all five balls, which are not due to friction losses.
For example, in a real Newton's cradle the fourth has some movement and the first ball has a slight reverse movement. All the animations in this article show idealized action that only occurs if the balls are not touching and only collide in pairs; the conservation of momentum and kinetic energy can be used to find the resulting velocities for two colliding elastic objects. These two equations are used to determine the resulting velocities of the two objects. For the case of two balls constrained to a straight path by the strings in the cradle, the velocities are a single number instead of a 3D vector for 3D space, so the math requires only two equations to solve for two unknowns; when the two objects weigh the same, the solution is simple: the moving object stops relative to the stationary one and the stationary one picks up all the other's initial velocity. This assumes elastic objects, so we do not need to account for heat and sound energy losses. Steel does not compress much, but its elasticity is efficient, so it does not cause much waste heat.
The simple effect from two same-weight efficiently elastic colliding objects constrained to a straight path is the basis of the interesting effect seen in the cradle and gives an approximate solution to all its activities. For a sequence of same-weight elastic objects constrained to a straight path, the effect continues to each successive object. For example, when two balls are dropped to strike three stationary balls in a cradle, there is an unnoticed but crucial small distance between the two dropped balls, the action is as follows: The first moving ball that strikes the first stationary ball transfers all its velocity to the third ball and stops; the third ball transfers the velocity to the fourth ball and stops, the fourth to the fifth ball. Right behind this sequence is the first ball transferring its velocity to the second ball that just stopped, the sequence repeats and imperceptibly behind the first sequence, ejecting the fourth ball right behind the fifth ball with the same small separation, between the two initial striking balls.
If they are touching when they strike the third ball, precision requires the more complete solution below. The interesting effect of the last ball ejecting with a velocity nearly equal to the first ball can be seen in sliding a coin on a table into a line of identical coins, as long as the striking coin and its twin targets are in a straight line; the effect can be seen in billiard balls. The effect can be seen when a sharp and strong pressure wave strikes a dense homogeneous material immersed in a less-dense medium. If the identical atoms, molecules, or larger-scale sub-volumes of the dense homogeneous material are at least elastically connected to each other by electrostatic forces, they can act as a sequence of colliding identical elastic balls; the surrounding atoms, molecules, or sub-volumes experiencing the pressure wave act to constrain each other to how the string constrains the cradle's balls to a straight line. For example, lithotripsy shock waves can be sent through the skin and tissue without harm to burst kidney stones.
The side of the stones opposite to the incoming pressure wave bursts, not the side receiving the initial strike. For the simple solu
The Royal Mint is a government-owned mint that produces coins for the United Kingdom. Operating under the name Royal Mint Ltd, the mint is a limited company, wholly owned by Her Majesty's Treasury and is under an exclusive contract to supply all the nation's coinage; as well as minting circulating coins for use domestically and internationally, the mint produces planchets, commemorative coins, various types of medals and precious metal bullion. The mint exports to an average of 60 countries a year. Formed over 1,100 years ago, the mint was part of a series of mints that became centralised to produce coins for the Kingdom of England, all of Great Britain and most of the British Empire; the original London mint from which the Royal Mint is the successor, was established in 886 AD and operated within the Tower of London for 800 years before moving to what is now called Royal Mint Court where it remained until the 1960s. As Britain followed the rest of the world in decimalising its currency, the Mint moved from London to a new 38 acres plant in Llantrisant, Wales where it has remained since.
In 2009 after recommendations for the mint to be privatised the Royal Mint ceased being an executive government agency and became a state-owned company wholly owned by HM Treasury. Since the mint has expanded its business interests by reviving its bullion trade and developing a £9 million visitor centre; the history of coins in Great Britain can be traced back to the second century BC when they were introduced by Celtic tribes from across the English Channel. The first record of coins being minted in Britain is attributed to Kentish tribes such as the Cantii who around 80–60 B. C. imitated those of Marseille through casting instead of hammering. After the Romans began their invasion of Britain in AD 43, they set up mints across the land, including in London which produced Roman coins for some 40 years before closing. A mint in London reopened in 383 AD until closing swiftly as Roman rule in Britain came to an end. For the next 200 years no coins appear to have been minted in Britain until the emergence of English kingdoms in 650 AD when as many as 30 mints are recorded across Britain with one being established in London.
Control of Britain's mints alternated. In 886 AD Alfred the Great recaptured London from the Danelaw and began issuing silver pennies bearing his portrait. In 1279, the country's numerous mints were unified under a single system whereby control was centralised to the mint within the Tower of London, mints outside of London were reduced with only a few local and episcopals continuing to operate. Pipe rolls detailing the financial records of the London mint show an expenditure of £729 17s 8½d and records of timber bought for workshops. Individual roles at the mint were well established by 1464; the master-worker was charged with hiring engravers and the management of moneyers, while the mint warden was responsible for witnessing the delivery of dies. A specialist mint board was set up in 1472 to enact a 23 February indenture which vested the mint's responsibilities into three main roles. In the 16th century having suffering from the effects of the Black Death, mainland Europe was in the middle of an economic expansion, England however was suffering with financial difficulty brought on by excessive government spending.
By the 1540s wars with France and Scotland led Henry VIII to enact The Great Debasement which saw the amount of precious metal in coin reduced. In order to further gather control of the country's currency, monasteries were dissolved which ended major coin production outside of London. In 1603, the union of Scotland and England under King James VI led to a partial union of both countries' currencies, the pound Scots and the pound sterling. Due to Scotland debasing its silver coins, a Scots mark was worth just 13.5d compared to an English mark, worth 6s 8d. To bridge the difference between the values, unofficial supplementary token coins made from lead were made by unauthorised minters across the country. By 1612 there were 3,000 such unlicensed mints producing these tokens, none of whom paying anything towards the crown; the Royal Mint, not wanting to divert manpower away from minting more profitable gold and silver, hired outside agent Lord Harington who under licence started issuing copper farthings in 1613.
Private licenses to mint these coins were revoked in 1644 which led traders to resume minting their own supplementary tokens. In 1672 the Royal Mint took over the production of copper coinage. Prior to the outbreak of the English Civil War, England signed a treaty in 1630 with Spain which ensured a steady supply of silver bullion to the Tower mint. Additional branch mints to aid the one in London were set up including one at Aberystwyth Castle, in Wales. In 1642 parliament seized control of the Tower mint and after Charles I tried to arrest the Five Members he was forced to flee London, establishing at least 16 emergency mints across the British Isles in Colchester, Cork, Dublin, Salisbury, parts of Cornwall including Truro, Worcester, Carlisle, Newark and Scarborough. After raising the royal standard in Nottingham marking the beginning of the war, Charles called upon loyalist mining engineer Thomas Bushell, the owner of a mint and silver mine in Aberystwyth, to move his operations to the royalist-held Shrewsbury within in the grounds of Shrewsbury Castle.
The mint there was however short-lived, operating for no more than three months before Charles ordered Bushell to re