Optics is the branch of physics that studies the behaviour and properties of light, including its interactions with matter and the construction of instruments that use or detect it. Optics describes the behaviour of visible and infrared light; because light is an electromagnetic wave, other forms of electromagnetic radiation such as X-rays and radio waves exhibit similar properties. Most optical phenomena can be accounted for using the classical electromagnetic description of light. Complete electromagnetic descriptions of light are, however difficult to apply in practice. Practical optics is done using simplified models; the most common of these, geometric optics, treats light as a collection of rays that travel in straight lines and bend when they pass through or reflect from surfaces. Physical optics is a more comprehensive model of light, which includes wave effects such as diffraction and interference that cannot be accounted for in geometric optics; the ray-based model of light was developed first, followed by the wave model of light.

Progress in electromagnetic theory in the 19th century led to the discovery that light waves were in fact electromagnetic radiation. Some phenomena depend on the fact that light has both particle-like properties. Explanation of these effects requires quantum mechanics; when considering light's particle-like properties, the light is modelled as a collection of particles called "photons". Quantum optics deals with the application of quantum mechanics to optical systems. Optical science is relevant to and studied in many related disciplines including astronomy, various engineering fields and medicine. Practical applications of optics are found in a variety of technologies and everyday objects, including mirrors, telescopes, microscopes and fibre optics. Optics began with the development of lenses by Mesopotamians; the earliest known lenses, made from polished crystal quartz, date from as early as 2000 BC from Crete. Lenses from Rhodes date around 700 BC; the ancient Romans and Greeks filled glass spheres with water to make lenses.

These practical developments were followed by the development of theories of light and vision by ancient Greek and Indian philosophers, the development of geometrical optics in the Greco-Roman world. The word optics comes from the ancient Greek word ὀπτική, meaning "appearance, look". Greek philosophy on optics broke down into two opposing theories on how vision worked, the intromission theory and the emission theory; the intromission approach saw vision as coming from objects casting off copies of themselves that were captured by the eye. With many propagators including Democritus, Epicurus and their followers, this theory seems to have some contact with modern theories of what vision is, but it remained only speculation lacking any experimental foundation. Plato first articulated the emission theory, the idea that visual perception is accomplished by rays emitted by the eyes, he commented on the parity reversal of mirrors in Timaeus. Some hundred years Euclid wrote a treatise entitled Optics where he linked vision to geometry, creating geometrical optics.

He based his work on Plato's emission theory wherein he described the mathematical rules of perspective and described the effects of refraction qualitatively, although he questioned that a beam of light from the eye could instantaneously light up the stars every time someone blinked. Euclid stated the principle of shortest trajectory of light, considered multiple reflections on flat and spherical mirrors. Ptolemy, in his treatise Optics, held an extramission-intromission theory of vision: the rays from the eye formed a cone, the vertex being within the eye, the base defining the visual field; the rays were sensitive, conveyed information back to the observer's intellect about the distance and orientation of surfaces. He summarized much of Euclid and went on to describe a way to measure the angle of refraction, though he failed to notice the empirical relationship between it and the angle of incidence. Plutarch described multiple reflections on spherical mirrors and discussed the creation of magnified and reduced images, both real and imaginary, including the case of chirality of the images.

During the Middle Ages, Greek ideas about optics were resurrected and extended by writers in the Muslim world. One of the earliest of these was Al-Kindi who wrote on the merits of Aristotelian and Euclidean ideas of optics, favouring the emission theory since it could better quantify optical phenomena. In 984, the Persian mathematician Ibn Sahl wrote the treatise "On burning mirrors and lenses" describing a law of refraction equivalent to Snell's law, he used this law to compute optimum shapes for curved mirrors. In the early 11th century, Alhazen wrote the Book of Optics in which he explored reflection and refraction and proposed a new system for explaining vision and light based on observation and experiment, he rejected the "emission theory" of Ptolemaic optics with its rays being emitted by the eye, instead put forward the idea that light reflected in all directions in straight lines from all points of the objects being viewed and entered the eye, although he was unable to explain how the eye captured the rays.

Alhazen's work was ignored in the Arabic world but it was anonymously translated into Latin around 1200 A. D. and further summarised and expanded on by the Polish monk Witelo making it a sta

Raffles Hotel, Perth

Raffles Hotel is located at the corner of Canning Highway and Canning Beach Road in the Perth suburb of Applecross, Western Australia. It is a two-storey hotel designed in the Inter-War Functionalist style and is one of the few examples of a hotel in this style surviving in the Perth metropolitan area. Earlier named the Canning Bridge Hotel, it has operated continuously as a licensed hotel since at least 1896. For over 50 years until 2002, it was owned by Australian nightclub owner and property developer Abe Saffron, whose plan to demolish the hotel was opposed by the Art Deco Society of Western Australia in a ten-year campaign; the location of Canning Bridge on the road from Fremantle to Perth and Guildford made it a suitable location for accommodation and refreshments. In January 1850 the first Canning Bridge was constructed and soon after, on 4 May, a liquor licence was granted to a Samuel Duffield, owner of the Bridge Inn of Canning, it is not known where that inn was located but it was a predecessor of the 1896 Canning Bridge Hotel, near the bridge on its western side—which was remodelled in 1937 as the present Raffles Hotel.

The Canning Bridge Hotel was a single-storey structure with a gabled roof. Beside it stood a pavilion with a dance hall on refreshment rooms below; the hotel provided a venue for many social and sporting groups such as the W. A. Hunt Club; the hotel was used by the East Fremantle District Road Board for its first council meeting on 22 March 1901. This building was extensively upgraded in 1937, with a distinctive Art Deco facade designed by architect William G. Bennett, to coincide with the construction of the current bridge and the upgrading of Canning Highway; the building was renamed the Raffles Hotel after the renowned Raffles Hotel in Singapore. The facade, in particular the nature and placement of the forward extension of the hotel, reveals a conscious effort on the part of the architect to respect the importance of the newly constructed Applecross District Hall to the community and its streetscape value. William Bennett had been a partner in the firm Eales Cohen & Bennett, responsible for the Applecross District Hall.

He left the firm in 1935. Other significant works by Bennett include the Plaza Theatre and Arcade in central Perth, the Kalgoorlie Olympic Pool, the Chalet at Araluen and other structures, the Beaucott Buildings in Beaufort Street; the hotel was reconstructed at a cost of 10,000 pounds. One of its features was a biergarten, believed to be the first of its kind in Australia; the garden was situated on the northern boundary of the hotel property. Raffles Hotel reveals the new design aesthetic in vogue of streamlined functional forms with an emphasis on horizontal lines admirably suited to the site, its design took good advantage of the riverside location. The main feature is the large curved loggias on both floors provided on the river frontage. From there, extensive views of the Swan and Canning Rivers are available; the exterior of the hotel was described as rendered in cream cement with sunk rustication emphasising the horizontal lines on the main building. The pitched roof over the first-storey section was covered in colour-blend tiles, green-painted circular steps led to the entrances of the hotel from the Canning Highway frontage.

Apart from its status as "the epitome" of Perth's social scene in the 1940s and 1950s, the Raffles became noted for its animated neon billboards advertising beer. In 1959 a separate motor lodge, consisting of a double-storey building of twenty rooms, was constructed at the rear of the main hotel building. According to the local press this new development met a public demand for motels offering service to the family man. Other changes to the hotel were made in 1985, when a fire caused damage to the first floor which required a new metal-deck roof to replace the former pitched tiled roof. A nightclub, The Raffs, was constructed on the eastern side of the building, a drive-in bottle shop built on the Canning Bridge Road frontage. During the 1970s and 1980s the Raffles was notable for its live music, attracting the most popular local and interstate acts. In 2002, the site was sold to the construction company Multiplex, which proceeded to redevelop the site into a 17-storey apartment tower; as part of the planning permissions, the Art Deco 1939 building was renovated.

The hotel was listed in the City of Melville's Municipal Heritage Inventory and classified by the National Trust of Western Australia on 3 July 1995. It received an interim listing on the State Register of Heritage Places on 16 March 2001, was nominated for the Register of the National Estate on 28 September 2001, received a permanent registration on the State Register on 22 January 2002. City for all Seasons: The Story of Melville Cooper, W S and McDonald, G A City of Melville ISBN 0-949663-02-6 The City of Melville - from bushland to expanding metropolis Uren, Malcolm City of Melville

Tim Waterstone

Sir Tim Waterstone is a British businessman and philanthropist. He is the founder of Waterstones, the United Kingdom-based bookselling retail chain, the largest in Europe. Tim Waterstone was born on 30 May 1939 in Scotland, he grew up in East Sussex, England. He was educated at Tonbridge School and St Catharine's College, where he read English. Waterstone worked for a broking firm in India. Upon his return to England he worked as a marketing manager for Allied Breweries, 1964–73 and W. H. Smith, 1973–81. Waterstone founded the bookselling chain Waterstone's in 1982, after he took a £6000 redundancy payment from W. H. Smith, he set up his first store in Old Brompton Road, west London. He became the founder chairman of HMV Media Group in 1998, which merged the businesses of Waterstone's and HMV, he left the group in 2001. Waterstone chaired the DTI Working Group on Smaller Quoted Companies and Private Investors in 1999, he was a founder investor in Bookberry, a Moscow booksellers modelled on Waterstone's.

He became the chairman of Read Petite, an e-book company, in 2013. Waterstone has published four novels: Lilley & Chase, An Imperfect Marriage, A Passage of Lives and In For A Penny In For A Pound, he has published a semi-autobiographical business book, Swimming Against The Stream and many articles in the arts and business media. His memoir, The Face Pressed Against A Window, was published by Atlantic Books in February 2019. Waterstone was a chairman or board member of English International, the London Philharmonic Orchestra, Portman House Trust, the Academy of Ancient Music, Virago Press, Jazz FM, the London International Festival of Theatre, the Elgar Foundation, the British Library, King's College London Library, Yale University Press, Chelsea Stores, FutureStart, Virago Press, Hill Samuel UK Emerging Companies Investment Trust plc and Downing Classic VCT, he has sat on the Booker Prize Management Committee, acted as the Chairman of Judges for the Prince's Youth Business Trust Awards. He served as a member of the visiting committee of Cambridge University Library.

He chaired Shelter's 25th Anniversary Appeal. He served as Chancellor of Edinburgh Napier University. Waterstone supports the Labour Party, he took part in demonstrations against it. Waterstone is twice divorced, he is married to novelist Rosie Alison. They have one of them being actress Daisy Waterstone, he resides in London. Waterstone is a member of the Garrick Club, he was knighted in the 2018 Birthday Honours for services to charity. Waterstones online