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Power Mac G5

The Power Mac G5 is a series of personal computers designed, manufactured, and sold by Apple Computer, Inc. from 2003 to 2006 as part of the Power Mac series. When introduced, it was the most powerful computer in Apple's Macintosh lineup, and was marketed by the company as the world's first 64-bit desktop computer. It was also the first desktop computer from Apple to use an anodized aluminum alloy enclosure, and one of only three computers in Apple's lineup to utilize the PowerPC 970 CPU, the others being the iMac G5 and the Xserve G5.

Three generations of Power Mac G5 were released before it was discontinued as part of the Mac transition to Intel processors, making way for its replacement, the Mac Pro. The Mac Pro retained a variation of the G5's enclosure design for seven more years, making it among the longest-lived designs in Apple's history.

Introduction
Officially launched as part of Steve Jobs' keynote presentation at the Worldwide Developers Conference in June 2003, the Power Mac G5 was introduced with three models, sharing the same physical case, but differing in features and performance. Although somewhat larger than the G4 tower it replaced, the necessity for a complex cooling system meant that the G5 tower had room inside for only one optical drive and two hard drives.

Steve Jobs stated during his keynote presentation that the Power Mac G5 would reach 3 GHz "within 12 months." This would never come to pass; after three years, the G5 only reached 2.7 GHz before it was replaced by the Intel Xeon-based Mac Pro, which debuted with processors running at speeds of up to 3 GHz.

During the presentation, Apple also showed Virginia Tech's Mac OS X computer cluster supercomputer (a.k.a. supercluster) known as System X, consisting of 1,100 Power Mac G5 towers operating as processing nodes. The supercomputer managed to become one of the top five supercomputers that year. The computer was soon dismantled and replaced with a new cluster made of an equal number of Xserve G5 rack-mounted servers, which also used the G5 chip running at 2.3 GHz.

PowerPC G5 and the IBM partnership

The PowerPC G5 (called the PowerPC 970 by its manufacturer, IBM) is based upon IBM's 64-bit POWER4 microprocessor. At the Power Mac G5's introduction, Apple announced a partnership with IBM in which IBM would continue to produce PowerPC variants of their POWER processors. According to IBM's Dr. John E. Kelly, "The goal of this partnership is for Apple and IBM to come together so that Apple customers get the best of both worlds, the tremendous creativity from the Apple corporation and the tremendous technology from the IBM corporation. IBM invested over US$3 billion in a new lab to produce these large, 300 mm wafers." This completely automated facility in East Fishkill, New York figured heavily in IBM's larger microelectronics strategy.

The original PowerPC 970 had 50 million transistors and was manufactured using IBM CMOS 9S at 130 nm fabrication process. CMOS 9S is the combination of SOI, low-k dielectric insulation, and copper interconnect technology, which were invented at IBM research in the mid-1990s. Subsequent revisions of the "G5" processor have included IBM's PowerPC 970FX (same basic design on a 90 nm process), and the PowerPC 970MP (essentially two 970FX cores on one die). Apple refers to the dual-core PowerPC 970MP processors as either the "G5 Dual" (for single-socket, dual-core configurations), or Power Mac G5 Quad (for dual-socket, four-core configurations).

Architecture
The Power Mac G5 line in 2006 consisted of three, dual-core PowerPC G5 configurations, which can communicate through its HyperTransport at half its internal clock speed. Each processor in the Power Mac G5 has two unidirectional 32-bit pathways: one leading to the processor and the other from the processor. These result in a total bandwidth of up to 20 GB/s. The processor at the heart of the Power Mac G5 has a "superscalar, superpipelined" execution core that can handle up to 216 in-flight instructions, and uses a 128-bit, 162-instruction SIMD unit (AltiVec).

All modern 32-bit x86 processors since the Pentium Pro have the Physical Address Extension (PAE) feature, which permits them to use a 36-bit physical memory address to address a maximum of 236 bytes (64 gigabytes) of physical memory, while the PowerPC 970 processor is capable of addressing 242 bytes (4 terabytes) of physical memory and 264 bytes (16 exabytes) of virtual memory. Due to its 64-bit processor (and 42-bit MMU), the final revision of the Power Mac G5 can hold 16 GB of Dual-Channel DDR2 PC4200 RAM using eight memory slots, with support for ECC memory.

Product revision history

 * 2003 June: Initial release at speeds of Single 1.6, Single 1.8, Dual 2.0 GHz.
 * 2003 November: Dual 1.8 replaces Single 1.8 GHz; price reduction on Single 1.6 GHz.
 * 2004 June: 90 nm Dual 1.8, Dual 2.0 and Dual 2.5 GHz replace all previous models. The 2.5 GHz model is notable as the first major PC with liquid cooling included as stock.
 * 2004 October: A new Single 1.8 reintroduced, with a slower, 600 MHz HyperTransport, PCI bus, based upon the iMac G5's architecture (U3lite and Shasta chips). Apple's official name for this machine is "Power Mac G5 (Late 2004)".
 * 2005 April: CPU speed increased: Dual 2.5 GHz → Dual 2.7 GHz (PCI-X, LC), Dual 2.0 GHz → Dual 2.3 GHz (PCI-X), Dual 1.8 GHz → Dual 2.0 GHz (PCI). Newly introduced features were the 16x dual-layer SuperDrives across the line and increased storage, up to 800 GB for the higher-end models. The 1.8 GHz Single was not modified.
 * 2005 June–July: The Single 1.8 model was discontinued in the United States and Europe.
 * 2005 October: Shift to dual-core processors: Dual 2.0 GHz → DC 2.0 GHz, Dual 2.3 GHz → DC 2.3 GHz, Dual 2.7 GHz → Dual DC 2.5 GHz (termed a Quad Power Mac G5, with four CPU execution cores and more reliable liquid cooling), all with DDR2 memory, and PCI Express expansion in place of PCI-X.  The older PCI-X, Dual 2.7 GHz model remained available for a while, but the slower speed single-core models were discontinued immediately.
 * 2006 August: The Power Mac is replaced by its Intel successor, the Mac Pro.

Defects
Early versions of dual processor G5 computers have noise problems. The first one is ground loop-based interference, which sometimes causes noise leaks into the analog audio outputs. This bug was fixed in Rev. B G5.

The second noise problem came from the 'chirping' sound, which can be triggered by fluctuations in power draw. For example, using Exposé causes a brief chirp. A widely circulated work-around is to disable the CPUs' "nap" feature using Apple's CHUD Tools, but this was not recommended by Apple. This noise problem was not fixed until the dual core generation of G5s was produced, however it did not affect the "Late 2004" model (at least there have never been any reports). The power draw fluctuation was later attributed to the lack of power management features in the single-core processors. Apple eventually posted the chirping bug information on its support site.

Although the noise problems did not prevent the affected computers from working, they were problematic for audio professionals and enthusiasts, especially for the liquid-cooled models, which had been expressly designed as mechanically quiet for discerning listeners.

A common problem among single processor G5s was the cyclic expansion and contraction of a metal plate soldered to the Logic Board connecting all eight of the RAM slots. Eventually, this can cause the computer to no longer detect the RAM, and refuse to boot. Fixes for this include having the plate re-soldered, or exposing the other side of the Logic Board to heat from a heat gun. The latter option is far easier, since it requires neither soldering nor the removal of the Logic Board from the computer.

All 2.5 GHz and 2.7 GHz dual processor models and the 2.5 GHz quad-processor model had a liquid cooling system that consisted of a radiator, coolant pump, and heat exchangers bolted to the processors. The cooling system was made by Delphi Automotive, a former Harrison Radiator Division of General Motors. This was a bold step for Apple, and should have allowed the use of very fast processors, giving Apple an advantage in both performance and reliability, but the system turned out to be subject to coolant leakage, made worse by the system's use of GM Dexcool coolant, which is more corrosive than regular automotive coolant. If not caught in time, the leakage could destroy the processors, logic board, and even corrode the aluminum casing itself. While leakage was sometimes detectable by drops of green coolant in or beneath the machine, in many machines the seepage is so slight that it was almost impossible to detect without dismantling the entire computer. Later models (only the 2.7 GHz) were equipped with a Panasonic liquid cooling system which was much more reliable.

The liquid cooling system fits into the case where the heat sinks would normally go, so there is no easy way to distinguish the liquid-cooled versions from the air-cooled, although most, but not all, of the liquid-cooled machines have a sticker inside warning about the possibility of leakage.

P.A. Semi's G5 derivative
When P.A. Semi announced the preliminary pre-production plan of PWRficient processor, there had been persistent rumors that Apple would prepare for its use in its professional line of personal computers.

In 2006, The Register reported that P.A. Semi had formed a tight relationship with Apple, which would result in P.A. Semi promptly delivering processor chips for Apple's personal computer notebook line and possibly desktops. Even in 2006, Apple did not have a laptop version of the G5 processor. The processor that would run the personal computers was P.A. Semi's preliminarily proposed processor, PWRficient 1682M (PA6T-1682M). The version that would be sampled for pre-production at third quarter of 2006 was a 2 GHz, dual-core CPU with two DDR2 memory controllers, 2 MB of L2 cache, and support for 8 PCI Express lanes. The sampled chip also has lower heat intensity than Intel's Core Duo, which gives off 9–31 W under normal load.

According to The Register article, P.A. Semi executives believed that they were all but assured of winning Apple's contract, and CEO Dan Dobberpuhl thought that Apple's hints of moving to Intel were just a persuading tactic. At the time, the companies were working for PWRficient software.

Despite the advantages of more compatible architecture, Apple moved to the Intel architecture officially for 'performance-per-watt' reasons. However, P.A. Semi would not be able to ship its low-power multicore product in volume until 2007, which, combined with P.A. Semi's status as a start-up company, seems to have been the final blow to the development of Power Mac computers. However, it was also speculated that Apple switched to Intel processor because Apple could no longer abide the constant delays in performance ramp up, desired native Windows compatibility, or it was Apple's strategy to shift its business focus away from desktop computing to iPod (and subsequently iOS) development.

Apple acquired P.A. Semi in 2008, using P.A. Semi's engineering resources to develop ARM CPUs for their iPhone, iPod Touch, iPad, and Apple TV product lines; and would go on to eventually come full circle with these designs replacing Intel chips in Macs in 2020.

The PA6T-1682M processor would later be used by the AmigaOne X1000 personal computer.

title: Power Mac G5


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Harry Potter and the Prisoner of Azkaban

Harry Potter and the Prisoner of Azkaban is a fantasy novel written by British author J. K. Rowling and is the third in the Harry Potter series. The book follows Harry Potter, a young wizard, in his third year at Hogwarts School of Witchcraft and Wizardry. Along with friends Ronald Weasley and Hermione Granger, Harry investigates Sirius Black, an escaped prisoner from Azkaban, the wizard prison, believed to be one of Lord Voldemort's old allies.

The book was published in the United Kingdom on 8 July 1999 by Bloomsbury and in the United States on 8 September 1999 by Scholastic, Inc. Rowling found the book easy to write, finishing it just a year after she began writing it. The book sold 68,000 copies in just three days after its release in the United Kingdom and since has sold over three million in the country. The book won the 1999 Whitbread Children's Book Award, the Bram Stoker Award, and the 2000 Locus Award for Best Fantasy Novel and was short-listed for other awards, including the Hugo.

The film adaptation of the novel was released in 2004, grossing more than $796 million and earning critical acclaim. Video games loosely based on Harry Potter and the Prisoner of Azkaban were also released for several platforms, and most obtained favourable reviews.

Plot
While Harry is living with the Dursleys, Aunt Marge comes to visit. When he and his late parents are insulted by Marge, an angry Harry accidentally inflates her. Harry packs up his stuff and leaves the house, choosing to spend the last weeks of summer at the Leaky Cauldron inn in London. While there, Harry is warned that a former follower of Voldemort, named Sirius Black, is seeking him out after having escaped from the wizard prison, Azkaban.

At Hogwarts, the guards of Azkaban, known as the Dementors, patrol the school looking for Black. Harry is unusually affected by their presence, and asks help from Remus Lupin, the new Defence Against the Dark Arts teacher, in learning to repel them. Lupin teaches Harry the incredibly difficult Patronus charm, but Harry isn't able to produce a full-bodied Patronus to fight off the Dementors. Meanwhile, Black is reported to have been sighted in the village of Hogsmeade, close to Hogwarts.

Harry is given a secret map by Fred and George Weasley, which reveals everyone inside the castle and its grounds. Harry uses it to sneak into Hogsmeade without permission. Hiding inside a pub, he overhears a conversation in which he learns that Black is actually his godfather, and that he killed his own best friend, Peter Pettigrew, while also betraying Harry's father, James, to Voldemort.

Harry, Ron and Hermione visit Hagrid at his hut, and are surprised to find Ron's missing pet rat, Scabbers, hiding there. As they walk back to the castle with Scabbers, Ron is attacked by a large dog. The dog drags Ron into a secret tunnel and disappears, coming out on the other side, inside the Shrieking Shack in Hogsmeade. The dog is revealed to be Black in his Animagus form.

Harry and Hermione reach the Shack, followed by Lupin, who spots them on Harry's map. Lupin disarms Harry, then explains why he believes Black to be innocent. Black claims that the crimes attributed to him were actually committed by Pettigrew, who escaped suspicion by faking his own death. Pettigrew is also an Animagus, and has been hiding as Ron's rat Scabbers this whole time. Harry suggests handing Pettigrew over to the Dementors.

While walking back to the castle, the full moon suddenly emerges and Lupin, secretly a werewolf, starts transforming. Black turns into the dog to protect the others, and Pettigrew escapes amid the chaos. Harry, Hermione and Black are accosted by Dementors, and Black ends up being captured.

While Black is held captive inside a tower in Hogwarts, Dumbledore confirms with Harry and Hermione that he is indeed innocent. He instructs them to save Black, by going back in time and setting him free, before he is handed over to the Dementors. Using a Time Turner, which Hermione has had since the beginning of the year to get to all her classes, they travel back a few hours. Present-day Harry saves his past self, and the past versions of Hermione and Black from Dementors using a Patronus. He then allows Black to be captured by Snape, before using Hagrid's hippogriff, Buckbeak, to release him from the tower and escape.

The next day, Lupin is forced to resign as his secret identity as a werewolf is now known to the school. Harry is upset at not spending more time with his godfather, Black, but Dumbledore asks him to take comfort in having saved his life. On the train journey back to London, Harry receives a letter from Black, who also sends a replacement pet owl for Ron.

Pre-release history
Harry Potter and the Prisoner of Azkaban is the third book in the Harry Potter series. The first, Harry Potter and the Philosopher's Stone, was published by Bloomsbury on 26 June 1997 and the second, Harry Potter and the Chamber of Secrets, was published on 2 July 1998. Rowling started to write the Prisoner of Azkaban the day after she finished The Chamber of Secrets. Rowling said in 2004 that Prisoner of Azkaban was "the best writing experience I ever had...I was in a very comfortable place writing (number) three. Immediate financial worries were over, and press attention wasn't yet by any means excessive".

Critical reception
Upon release, Harry Potter and the Prisoner of Azkaban received mostly positive reviews. The Guardian reported an average rating of 9 out of 10 for the book based on reviews from multiple British newspapers. Gregory Maguire wrote a review in The New York Times for Prisoner of Azkaban: in it he said, "So far, in terms of plot, the books do nothing new, but they do it brilliantly...so far, so good." In a newspaper review in The New York Times, it was said that "'The Prisoner of Azkaban' may be the best 'Harry Potter' book yet". A reviewer for KidsReads said, "This crisply-paced fantasy will leave you hungry for the four additional Harry books that J.K. Rowling is working on. Harry's third year is a charm. Don't miss it." Kirkus Reviews did not give a starred review but said, "a properly pulse-pounding climax...The main characters and the continuing story both come along so smartly...that the book seems shorter than its page count: have readers clear their calendars if they are fans, or get out of the way if they are not." Martha V. Parravano also gave a positive review for The Horn Book Magazine, calling it "quite a good book." In addition, a Publishers Weekly review said, "Rowling's wit never flags, whether constructing the workings of the wizard world...or tossing off quick jokes...The Potter spell is holding strong".

However, Anthony Holden, who was one of the judges against Prisoner of Azkaban for the Whitbread Award, was negative about the book, saying that the characters are "all black-and-white", and the "story-lines are predictable, the suspense minimal, the sentimentality cloying every page".

In 2012 it was ranked number 12 on a list of the top 100 children's novels published by School Library Journal.

Awards
Harry Potter and the Prisoner of Azkaban won several awards, including the 1999 Booklist Editors' Choice Award, the 1999 Bram Stoker Award for Best Work for Young Readers, the 1999 FCBG Children's Book Award, the 1999 Whitbread Book of the Year for children's books, and the 2000 Locus Award for Best Fantasy Novel. It was also nominated for the 2000 Hugo Award for Best Novel, the first in the series nominated, but lost to A Deepness in the Sky. Prisoner of Azkaban additionally won the 2004 Indian Paintbrush Book Award and the 2004 Colorado Blue Spruce Young Adult Book Award. Additionally, it was named an American Library Association Notable Children's Book in 2000 as well as one of their Best Books for Young Adults. As with the previous two books in the series, Prisoner of Azkaban won the Nestlé Smarties Book Prize Gold Medal for children aged 9–11 and made the top of the New York Times Best Seller list. In both cases, it was the last in the series to do so. However, in the latter case, a Children's Best Sellers list was created just before the release of Harry Potter and the Goblet of Fire in July 2000 in order to free up more room on the original list. In 2003, the novel was listed at number 24 on the BBC's survey The Big Read.

Sales
Prisoner of Azkaban sold more than 68,000 copies in the UK within three days of publication, which made it the fastest selling British book of the time. The sales total by 2012 is said by The Guardian to be 3,377,906.

Editions
Harry Potter and the Prisoner of Azkaban was issued, prior to publication, in two distinct UK proof editions, and one US "Advance Reader's Edition". The first UK proof, in purple wrappers, differs from the second in a number of respects, and is thought to have been printed in a small edition of 50 copies. The second UK proof is in green wrappers and was printed in a somewhat larger run. The US Advance Reader's Edition is the last of its kind in the Harry Potter series, as no Advance Reader's Editions are known for books 4 through 7. The rear wrapper of the Advance Reader's Edition reveals the circumstances of the US publication of the book:

"Due to the unprecedented demand for this book, we have moved the publication date up a full year. (We understand, we couldn’t wait to read it either!). Accordingly, we have rushed to bring this Advance Reader’s Edition to you as quickly as possible."

Harry Potter and the Prisoner of Azkaban was released in hardcover in the UK on 8 July 1999 and in the US on 8 September. The UK edition was released at the unusually precise time of 3.45pm, so as to avoid children skipping school in order to purchase the book. The first state of the hardback edition features an error on p. 7, with an unintended carriage return in a block quote. Two further issues were released, both fixing the error. Across all three states, 5,150 were printed by Clays Ltd.

The British paperback edition was released on 1 April 2000, while the US paperback was released 1 October 2001.

Bloomsbury additionally released an adult edition with a different cover design to the original, in paperback on 10 July 2004 and in hardcover in October 2004. A hardcover special edition, featuring a green border and signature, was released on 8 July 1999. In May 2004, Bloomsbury released a Celebratory Edition, with a blue and purple border. On 1 November 2010, they released the 10th anniversary Signature edition illustrated by Clare Mellinsky and in July 2013 a new adult cover illustrated by Andrew Davidson, both these editions were designed by Webb & Webb Design Limited.

Beginning on 27 August 2013, Scholastic will release new covers for the paperback editions of Harry Potter in the United States to celebrate 15 years of the series. The covers were designed by the author and illustrator Kazu Kibuishi.

An illustrated version of Harry Potter and the Prisoner of Azkaban was released on 3 October 2017, and was illustrated by Jim Kay, who illustrates the previous two instalments. This includes over 115 new illustrations and will be followed by Illustrated editions of the following 4 novels in the future. Jim Kay announced on 6 October 2022 that he would not be illustrating the final two Harry Potter books and that his last work, Harry Potter and the Order of the Phoenix, would be released on 11 October 2022.

Film
The film version of Harry Potter and the Prisoner of Azkaban was released in 2004 and was directed by Alfonso Cuarón from a screenplay by Steve Kloves. The film débuted at number one at the box office and held that position for two weeks. It made a total of $796.7 million worldwide, which made it the second highest-grossing film of 2004 behind Shrek 2. However, among all eight entries in the Harry Potter franchise, Prisoner of Azkaban grossed the lowest; yet among critics and fans, the film is often cited as the best in the franchise – in large part due to Cuarón's stylistic influence. The film ranks at number 471 in Empire magazine's 2008 list of the 500 greatest movies of all time.

Video games
Three unique video games by different developers were released in 2004 by Electronic Arts, loosely based on the book:

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


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M. F. Korn

Michael F. Korn is an American author who writes horror and science fiction. He has written eleven novels and his stories have appeared in over 220 magazines worldwide. He lives in Louisiana.

title: M. F. Korn


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OMB

OMB may refer to:

 * East Ambae language (ISO 639-3 code: omb), an Oceanic language spoken on Ambae, Vanuatu
 * Office of Management and Budget, the largest office within the Executive Office of the President of the United States
 * Olympiade Mathématique Belge, a mathematical competition for students in grades 7 to 12
 * OMB, a graphic design studio founded by Oscar Mariné
 * Ontario Municipal Board, an independent administrative board in the province of Ontario, Canada
 * Optical Media Board, a national agency under the Office of the President of the Philippines
 * Oregon Marching Band, the marching band of the University of Oregon
 * Oregon Medical Board, state agency responsible for establishing the rules and regulations for medicine

title: OMB


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User talk:TheOmnilord

Hello Omnilord, welcome to Wikipedia. I hope you enjoy editing here and being a Wikipedian. You can learn more on the how to edit page. The naming conventions and manual of style pages are also useful. Feel free to experiment at the Sandbox. If you have any questions about the project then check out Help or add a question to the Village pump. Angela

Any comments on contributions I have made would be appreciated.

-TheOmnilord

title: User talk:TheOmnilord


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Percy Grainger

Percy Aldridge Grainger (born George Percy Grainger; 8 July 1882 – 20 February 1961) was an Australian-born composer, arranger and pianist who moved to the United States in 1914 and became an American citizen in 1918. In the course of a long and innovative career he played a prominent role in the revival of interest in British folk music in the early years of the 20th century. Although much of his work was experimental and unusual, the piece with which he is most generally associated is his piano arrangement of the folk-dance tune "Country Gardens".

Grainger left Australia at the age of 13 to attend the Hoch Conservatory in Frankfurt. Between 1901 and 1914 he was based in London, where he established himself first as a society pianist and later as a concert performer, composer, and collector of original folk melodies. As his reputation grew he met many of the significant figures in European music, forming important friendships with Frederick Delius and Edvard Grieg. He became a champion of Nordic music and culture, his enthusiasm for which he often expressed in private letters, sometimes in crudely racial or anti-Semitic terms.

In 1914, Grainger moved to the United States, where he lived for the rest of his life, though he travelled widely in Europe and Australia. He served briefly as a bandsman in the United States Army during the First World War through 1917–18, and took American citizenship in 1918. After his mother's suicide in 1922, he became increasingly involved in educational work. He also experimented with music machines, which he hoped would supersede human interpretation. In the 1930s he set up the Grainger Museum in Melbourne, his birthplace, as a monument to his life and works, and as a future research archive. As he grew older, he continued to give concerts and to revise and rearrange his own compositions, while writing little new music. After the Second World War, ill health reduced his levels of activity. He considered his career a failure. He gave his last concert in 1960, less than a year before his death.

Family background
Grainger was born on 8 July 1882 in Brighton, south-east of Melbourne. His father, John Grainger, an English-born architect who had emigrated to Australia in 1877, won recognition for his design of the Princes Bridge across the Yarra River in Melbourne; His mother Rose Annie Aldridge was the daughter of Adelaide hotelier George Aldridge.

John Grainger was an accomplished artist, with broad cultural interests and a wide circle of friends. These included David Mitchell, whose daughter Helen later gained worldwide fame as an operatic soprano under the name Nellie Melba. John's claims to have "discovered" her are unfounded, although he may have offered her encouragement. John was a heavy drinker and a womaniser who, Rose learned after the marriage, had fathered a child in England before coming to Australia. His promiscuity placed deep strains upon the relationship. Rose discovered shortly after Percy's birth that she had contracted a form of syphilis from her husband. Despite this, the Graingers stayed together until 1890, when John went to England for medical treatment. After his return to Australia, they lived apart. Rose took over the work of raising Percy, while John pursued his career as chief architect to the Western Australian Department of Public Works. He had some private work, designing Nellie Melba's home, Coombe Cottage, at Coldstream.

Childhood
Except for three months' formal schooling as a 12-year-old, during which he was bullied and ridiculed by his classmates, Percy was educated at home. Rose, an autodidact with a dominating presence, supervised his music and literature studies and engaged other tutors for languages, art and drama. From his earliest lessons, Percy developed a lifelong fascination with Nordic culture; writing late in life, he said that the Icelandic Saga of Grettir the Strong was "the strongest single artistic influence on my life". As well as showing precocious musical talents, he displayed considerable early gifts as an artist, to the extent that his tutors thought his future might lie in art rather than music. At the age of 10 he began studying piano under Louis Pabst, a German-born graduate of the Moscow Conservatory, Melbourne's leading piano teacher. Grainger's first known composition, "A Birthday Gift to Mother", is dated 1893. Pabst arranged Grainger's first public concert appearances, at Melbourne's Masonic Hall in July and September 1894. The boy played works by Bach, Beethoven, Schumann and Scarlatti, and was warmly complimented in the Melbourne press.

After Pabst returned to Europe in the autumn of 1894, Grainger's new piano tutor, Adelaide Burkitt, arranged for his appearances at a series of concerts in October 1894 at Melbourne's Royal Exhibition Building. The size of this enormous venue horrified the young pianist; nevertheless, his performance delighted the Melbourne critics, who dubbed him "the flaxen-haired phenomenon who plays like a master". This public acclaim helped Rose to decide that her son should continue his studies at the Hoch Conservatory in Frankfurt, Germany, an institution recommended by William Laver, head of piano studies at Melbourne's Conservatorium of music. Financial assistance was secured through a fund-raising benefit concert in Melbourne and a final recital in Adelaide, after which mother and son left Australia for Europe on 29 May 1895. Although Grainger never returned permanently to Australia, he maintained considerable patriotic feelings for his native land, and was proud of his Australian heritage.

Frankfurt
In Frankfurt, Rose established herself as a teacher of English; her earnings were supplemented by contributions from John Grainger, who had settled in Perth. The Hoch Conservatory's reputation for piano teaching had been enhanced by the tenure, until 1892, of Clara Schumann as head of piano studies. Grainger's piano tutor was James Kwast, who developed his young pupil's skills to the extent that, within a year, Grainger was being lauded as a prodigy. Grainger had difficult relations with his original composition teacher, Iwan Knorr; he withdrew from Knorr's classes to study composition privately with Karl Klimsch, an amateur composer and folk-music enthusiast, whom he would later honour as "my only composition teacher".

Together with a group of slightly older British students – Roger Quilter, Balfour Gardiner, Cyril Scott and Norman O'Neill, all of whom became his friends – Grainger helped form the Frankfurt Group. Their long-term objective was to rescue British and Scandinavian music from what they considered the negative influences of central European music. Encouraged by Klimsch, Grainger turned away from composing classical pastiches reminiscent of Handel, Haydn and Mozart, and developed a personal compositional style, the originality and maturity of which quickly impressed and astonished his friends. At this time Grainger discovered the poetry of Rudyard Kipling and began setting it to music; according to Scott, "No poet and composer have been so suitably wedded since Heine and Schumann."

After accompanying her son on an extended European tour in the summer of 1900, Rose, whose health had been poor for some time, suffered a nervous collapse and could no longer work. To replace lost income, Grainger began giving piano lessons and public performances; his first solo recital was in Frankfurt on 6 December 1900. Meanwhile, he continued his studies with Kwast, and increased his repertoire until he was confident he could support himself and his mother as a concert pianist. Having chosen London as his future base, in May 1901 Grainger abandoned his studies. With Rose, he left Frankfurt for the UK.

Before leaving Frankfurt, Grainger had fallen in love with Kwast's daughter Mimi. In an autobiographical essay dated 1947, he says that he was "already sex-crazy" at this time, when he was 19. John Bird, Grainger's biographer, records that during his Frankfurt years, Grainger began to develop sexual appetites that were "distinctly abnormal"; by the age of 16 he had started to experiment in flagellation and other sado-masochistic practices, which he continued to pursue through most of his adult life. Bird surmises that Grainger's fascination with themes of punishment and pain derived from the harsh discipline to which Rose had subjected him as a child.

Concert pianist
In London, Grainger's charm, good looks and talent (with some assistance from the local Australian community) ensured that he was quickly taken up as a pianist by wealthy patrons. He was soon performing in concerts in private homes. The Times critic reported after one such appearance that Grainger's playing "revealed rare intelligence and a good deal of artistic insight". In 1902 he was presented by the socialite Lillith Lowrey to Queen Alexandra, who thereafter frequently attended his London recitals. Lowrey, 20 years Grainger's senior, traded patronage and contacts for sexual favours – he termed the relationship a "love-serve job". She was the first woman with whom he had sex; he later wrote of this initial encounter that he had experienced "an overpowering landslide" of feeling, and that "I thought I was about to die. If I remember correctly, I only experienced fear of death. I don't think that any joy entered into it".

In February 1902 Grainger made his first appearance as a piano soloist with an orchestra, playing Tchaikovsky's first piano concerto with the Bath Pump Room Orchestra. In October of that year he toured Britain in a concert party with Adelina Patti, the Italian-born opera singer. Patti was greatly taken by the young pianist and prophesied a glorious career for him. The following year he met the German-Italian composer and pianist Ferruccio Busoni. Initially the two men were on cordial terms (Busoni offered to give Grainger lessons free of charge) and, as a result, Grainger spent part of the 1903 summer in Berlin as Busoni's pupil. However, the visit was not a success; as Bird notes, Busoni had expected "a willing slave and adoring disciple", a role Grainger was not willing to fulfil. Grainger returned to London in July 1903; almost immediately he departed with Rose on a 10-month tour of Australia, New Zealand and South Africa, as a member of a party organised by the Australian contralto Ada Crossley.

Emergent composer
Before going to London Grainger had composed numerous Kipling settings, and his first mature orchestral pieces. In London, when he found time he continued to compose; a letter to Balfour Gardiner dated 21 July 1901 indicates that he was working on his Marching Song of Democracy (a Walt Whitman setting), and had made good progress with the experimental works Train Music and Charging Irishrey. In his early London years he also composed Hill Song Number 1 (1902), an instrumental piece much admired by Busoni. In 1905, inspired by a lecture given by the pioneer folk-song historian Lucy Broadwood, Grainger began to collect original folk songs. Starting at Brigg in Lincolnshire, over the next five years he gathered and transcribed more than 300 songs from all over the country, including much material that had never been written down before. From 1906 Grainger used a phonograph, one of the first collectors to do so, and by this means he assembled more than 200 Edison cylinder recordings of native folk singers. These activities coincided with what Bird calls "the halcyon days of the 'First English Folksong Revival'".

As his stature in the music world increased, Grainger became acquainted with many of its leading figures, including Vaughan Williams, Elgar, Richard Strauss and Debussy. In 1907 he met Frederick Delius, with whom he achieved an immediate rapport – the two musicians had similar ideas about composition and harmony, and shared a dislike for the classical German masters. Both were inspired by folk music; Grainger gave Delius his setting of the folk song Brigg Fair, which the older composer developed into his well-known orchestral rhapsody, dedicated to Grainger. The two remained close friends until Delius's death in 1934.

Grainger first met Edvard Grieg at the home of the London financier Sir Edgar Speyer, in May 1906. As a student, Grainger had learned to appreciate the Norwegian's harmonic originality, and by 1906 had several Grieg pieces in his concert repertoire, including the piano concerto. Grieg was greatly impressed with Grainger's playing, and wrote: "I have written Norwegian Peasant Dances that no one in my country can play, and here comes this Australian who plays them as they ought to be played! He is a genius that we Scandinavians cannot do other than love." During 1906–07 the two maintained a mutually complimentary correspondence, which culminated in Grainger's ten-day visit in July 1907 to the composer's Norwegian home, "Troldhaugen" near Bergen. Here the two spent much time revising and rehearsing the piano concerto in preparation for that year's Leeds Festival. Plans for a long-term working relationship were ended by Grieg's sudden death in September 1907; nevertheless, this relatively brief acquaintance had a considerable impact on Grainger, and he championed Grieg's music for the rest of his life. After fulfilling a hectic schedule of concert engagements in Britain and continental Europe, in August 1908 Grainger accompanied Ada Crossley on a second Australasian tour, during which he added several cylinders of Maori and Polynesian music to his collection of recordings. He had resolved to establish himself as a top-ranking pianist before promoting himself as a composer, though he continued to compose both original works and folk-song settings. Some of his most successful and most characteristic pieces, such as "Mock Morris", "Handel in the Strand", "Shepherd's Hey" and "Molly on the Shore" date from this period. In 1908 he obtained the tune of "Country Gardens" from the folk music specialist Cecil Sharp, though he did not fashion it into a performable piece for another ten years.

In 1911 Grainger finally felt confident enough of his standing as a pianist to begin large-scale publishing of his compositions. At the same time, he adopted the professional name of "Percy Aldridge Grainger" for his published compositions and concert appearances. In a series of concerts arranged by Balfour Gardiner at London's Queen's Hall in March 1912, five of Grainger's works were performed to great public acclaim; the band of thirty guitars and mandolins for the performance of "Fathers and Daughters" created a particular impression. On 21 May 1912 Grainger presented the first concert devoted entirely to his own compositions, at the Aeolian Hall, London; the concert was, he reported, "a sensational success". A similarly enthusiastic reception was given to Grainger's music at a second series of Gardiner concerts the following year.

In 1905 Grainger began a close friendship with Karen Holten, a Danish music student who had been recommended to him as a piano pupil. She became an important confidante; the relationship persisted for eight years, largely through correspondence. After her marriage in 1916, she and Grainger continued to correspond and occasionally met until her death in 1953. Grainger was briefly engaged in 1913 to another pupil, Margot Harrison, but the relationship foundered through a mixture of Rose's over-possessiveness and Grainger's indecision.

Departure for America
In April 1914 Grainger gave his first performance of Delius's piano concerto, at a music festival in Torquay. Thomas Beecham, who was one of the festival's guest conductors, reported to Delius that "Percy was good in the forte passages, but made far too much noise in the quieter bits". Grainger was receiving increasing recognition as a composer; leading musicians and orchestras were adding his works to their repertoires. His decision to leave England for America in early September 1914, after the outbreak of the First World War, damaged his reputation among his patriotically minded British friends. Grainger wrote that the reason for this abrupt departure was "to give mother a change" – she had been unwell for years. However, according to Bird, Grainger often explained that his reason for leaving London was that "he wanted to emerge as Australia's first composer of worth, and to have laid himself open to the possibility of being killed would have rendered his goal unattainable". The Daily Telegraph music critic Robin Legge accused him of cowardice, and told him not to expect a welcome in England after the war, words that hurt Grainger deeply.

Grainger's first American tour began on 11 February 1915 with a recital at New York's Aeolian Hall. He played works by Bach, Brahms, Handel and Chopin alongside two of his own compositions: "Colonial Song" and "Mock Morris". In July 1915 Grainger formally registered his intention to apply for US citizenship. Over the next two years his engagements included concerts with Melba in Boston and Pittsburgh and a command performance before President Woodrow Wilson. In addition to his concert performances, Grainger secured a contract with Duo-Art for making pianola rolls, and signed a recording contract with Columbia Records.

In April 1917 Grainger received news of his father's death in Perth. On 9 June 1917, after America's entry into the war, he enlisted as a bandsman in the US Army with the military band of the 15th Coast Artillery in Fort Hamilton. He had joined as a saxophonist, though he records learning the oboe: "I long for the time when I can blow my oboe well enough to play in the band". In his 18 months' service, Grainger made frequent appearances as a pianist at Red Cross and Liberty bond concerts. As a regular encore he began to play a piano setting of the tune "Country Gardens". The piece became instantly popular; sheet music sales quickly broke many publishing records. The work was to become synonymous with Grainger's name through the rest of his life, though he came in time to detest it. On 3 June 1918 he became a naturalised American citizen.

Career zenith
After leaving the army in January 1919, Grainger refused an offer to become conductor of the Saint Louis Symphony Orchestra and resumed his career as a concert pianist. He was soon performing around 120 concerts a year, generally to great critical acclaim, and in April 1921 reached a wider audience by performing in a cinema, New York's Capitol Theatre. Grainger commented that the huge audiences at these cinema concerts often showed greater appreciation for his playing than those at established concert venues such as Carnegie Hall and the Aeolian. In the summer of 1919 he led a course in piano technique at Chicago Musical College, the first of many such educational duties he would undertake in later years.

Amid his concert and teaching duties, Grainger found time to re-score many of his works (a habit he continued throughout his life) and also to compose new pieces: his Children's March: Over the Hills and Far Away, and the orchestral version of The Power of Rome and the Christian Heart both originated in this period. He also began to develop the technique of elastic scoring, a form of flexible orchestration which enabled works to be performed by different numbers of players and instrument types, from small chamber groups up to full orchestral strength.

In April 1921 Grainger moved with his mother to a large house in White Plains, New York in what is now known as the Percy Grainger Home and Studio. This was his home for the remainder of his life. From the beginning of 1922 Rose's health deteriorated sharply; she was suffering from delusions and nightmares, and became fearful that her illness would harm her son's career. Because of the closeness of the bond between the two, there had long been rumours that their relationship was incestuous; in April 1922 Rose was directly challenged over this issue by her friend Lotta Hough. From her last letter to Grainger, dated 29 April, it seems that this confrontation unbalanced Rose; on 30 April, while Grainger was touring on the West Coast, she jumped to her death from an office window on the 18th floor of the Aeolian Building in New York City. The letter, which began "I am out of my mind and cannot think properly", asked Grainger if he had ever spoken to Lotta of "improper love". She signed the letter: "Your poor insane mother".

European Travels
After Rose's funeral, Grainger sought solace in a return to work. In autumn 1922 he left for a year-long trip to Europe, where he collected and recorded Danish folk songs before a concert tour that took him to Norway, the Netherlands, Germany and England. In Norway he stayed with Delius at the latter's summer home. Delius was by now almost blind; Grainger helped fulfill his friend's wish to see a Norwegian sunset by carrying him (with some assistance) to the top of a nearby mountain peak. He returned to White Plains in August 1923.

Although now less committed to a year-round schedule of concerts, Grainger remained a very popular performer. His eccentricities, often exaggerated for publicity reasons, reportedly included running into auditoriums in gym kit and leaping over the piano to create a grand entrance. In 1924, Grainger became a vegetarian, although he hated vegetables; his diet comprised primarily dairy, pastry, fruit, and nuts.

While he continued to revise and re-score his compositions, he increasingly worked on arrangements of music by other composers, in particular works by Bach, Brahms, Fauré and Delius. Away from music, Grainger's preoccupation with Nordic culture led him to develop a form of English which, he maintained, reflected the character of the language before the Norman conquest. Words of Norman or Latin origin were replaced by supposedly Nordic word-forms, such as "blend-band" (orchestra), "forthspeaker" (lecturer) and "writ-piece" (article). He called this "blue-eyed" English. His convictions of Nordic superiority eventually led Grainger, in letters to friends, to express his views in crudely racial and anti-Semitic terms; the music historian David Pear describes Grainger as, "at root, a racial bigot of no small order".

Grainger made further trips to Europe in 1925 and 1927, collecting more Danish folk music with the aid of the octogenarian ethnologist Evald Tang Kristensen; this work formed the basis of the Suite on Danish Folksongs of 1928–30. He also visited Australia and New Zealand, in 1924 and again in 1926.

Marriage
In November 1926, while returning to America, he met Ella Ström, a Swedish-born artist with whom he developed a close friendship. On arrival in America the pair separated, but were reunited in England the following autumn after Grainger's final folk-song expedition to Denmark. In October 1927 the couple agreed to marry. Ella had a daughter, Elsie, who had been born out of wedlock in 1909. Grainger always acknowledged her as a family member, and developed a warm personal relationship with her.

Although Bird asserts that before her marriage, Ella knew nothing of Grainger's sado-masochistic interests, in a letter dated 23 April 1928 (four months before the wedding) Grainger writes to her: "As far as my taste goes, blows [with the whip] are most thrilling on breasts, bottom, inner thighs, sexparts." He later adds, "I shall thoroly thoroly [sic] understand if you cannot in any way see yr way to follow up this hot wish of mine."

The couple were married on 9 August 1928 at the Hollywood Bowl, at the end of a concert which, in honour of the bride, had included the first performance of Grainger's bridal song "To a Nordic Princess".

Educator
From the late 1920s and early 1930s Grainger became involved increasingly with educational work in schools and colleges, and in late 1931 accepted a year's appointment for 1932–33 as professor of music at New York University (NYU). In this role he delivered a series of lectures under the heading "A General Study of the Manifold Nature of Music", which introduced his students to a wide range of ancient and modern works. On 25 October 1932 his lecture was illustrated by Duke Ellington and his band, who appeared in person; Grainger admired Ellington's music, seeing harmonic similarities with Delius. On the whole, however, Grainger did not enjoy his tenure at NYU; he disliked the institutional formality, and found the university generally unreceptive to his ideas. Despite many offers he never accepted another formal academic appointment, and refused all offers of honorary degrees. His New York lectures became the basis for a series of radio talks which he gave for the Australian Broadcasting Commission in 1934–35; these were later summarised and published as Music: A Commonsense View of All Types. In 1937 Grainger began an association with the Interlochen National Music Camp, and taught regularly at its summer schools until 1944.

Innovator
The idea of establishing a Grainger Museum in Australia had first occurred to Grainger in 1932. He began collecting and recovering from friends letters and artefacts, even those demonstrating the most private aspects of his life, such as whips, bloodstained shirts and revealing photographs. In September 1933 he and Ella went to Australia to begin supervising the building work. To finance the project, Grainger embarked on a series of concerts and broadcasts, in which he subjected his audiences to a vast range of the world's music in accordance with his "universalist" view. Controversially, he argued for the superior achievements of Nordic composers over traditionally recognised masters such as Mozart and Beethoven.

Among various new ideas, Grainger introduced his so-called "free-music" theories. He believed that conformity with the traditional rules of set scales, rhythms and harmonic procedures amounted to "absurd goose-stepping", from which music should be set free. He demonstrated two experimental compositions of free music, performed initially by a string quartet and later by the use of electronic theremins. He believed that ideally, free music required non-human performance, and spent much of his later life developing machines to realise this vision.

While the building of the museum proceeded, the Graingers visited England for several months in 1936, during which Grainger made his first BBC broadcast. In this, he conducted "Love Verses from The Song of Solomon" in which the tenor soloist was the then unknown Peter Pears. After spending 1937 in America, Grainger returned to Melbourne in 1938 for the official opening of the Museum; among those present at the ceremony was his old piano teacher Adelaide Burkitt. The museum did not open to the general public during Grainger's lifetime, but was available to scholars for research.

In the late 1930s Grainger spent much time arranging his works in settings for wind bands. He wrote Lincolnshire Posy for the March 1937 convention of the American Band Masters' Association in Milwaukee, and in 1939, on his last visit to England before the Second World War, he composed "The Duke of Marlborough's Fanfare", giving it the subtitle "British War Mood Grows".

Second World War
The outbreak of war in Europe in September 1939 curtailed Grainger's overseas travelling. In the autumn of 1940, alarmed that the war might precipitate an invasion of the United States eastern seaboard, he and Ella moved to Springfield, Missouri, in the centre of the continent. From 1940 Grainger played regularly in charity concerts, especially after the attack on Pearl Harbor brought the United States into the war in December 1941; the historian Robert Simon calculates that Grainger made a total of 274 charity appearances during the war years, many of them at Army and Air Force camps. In 1942 a collection of his Kipling settings, the Jungle Book cycle, was performed in eight cities by the band of the Gustavus Adolphus College from St. Peter, Minnesota.

Postwar decline
Exhausted from his wartime concerts routine, Grainger spent much of 1946 on holiday in Europe. He was suffering a sense of career failure; in 1947, when refusing the Chair of Music at Adelaide University, he wrote: "If I were 40 years younger, and not so crushed by defeat in every branch of music I have essayed, I am sure I would have welcomed such a chance". In January 1948 he conducted the premiere of his wind band setting of The Power of Rome and the Christian Heart, written for the Goldman Band to celebrate the 70th birthday of its founder. Afterward, Grainger denigrated his own music as "commonplace" while praising Darius Milhaud's Suite Française, with which it had shared the programme.

On 10 August 1948, Grainger appeared at the London Proms, playing the piano part in his Suite on Danish Folksongs with the London Symphony Orchestra under Basil Cameron. On 18 September he attended the Last Night of the Proms, standing in the promenade section for Delius's Brigg Fair. Over the next few years several friends died: Gardiner in 1950, Quilter and Karen Holten in 1953. In October 1953 Grainger was operated on for abdominal cancer; his fight against this disease would last for the rest of his life. He continued to appear at concerts, often performed in church halls and educational establishments rather than major concert venues.

In 1954, after his last Carnegie Hall appearance, Grainger's long promotion of Grieg's music was recognised when he was awarded the St. Olav Medal by King Haakon of Norway. But he expressed a growing bitterness in his writings and correspondence; in a letter to the Danish composer Herman Sandby, a lifelong friend, he bemoaned the continuing ascendency in music of the "German form", and asserted that "all my compositional life I have been a leader without followers".

After 1950 Grainger virtually ceased to compose. His principal creative activity in the last decade of his life was his work with Burnett Cross, a young physics teacher, on free music machines. The first of these was a relatively simple device controlled by an adapted pianola. Next was the "Estey-reed tone-tool", a form of giant harmonica which, Grainger expectantly informed his stepdaughter Elsie in April 1951, would be ready to play free music "in a few weeks". A third machine, the "Cross-Grainger Kangaroo-pouch", was completed by 1952. Developments in transistor technology encouraged Grainger and Cross to begin work on a fourth, entirely electronic machine, which was incomplete when Grainger died.

In September 1955 Grainger made his final visit to Australia, where he spent nine months organising and arranging exhibits for the Grainger Museum. He refused to consider a "Grainger Festival", as suggested by the Australian Broadcasting Commission, because he felt that his homeland had rejected him and his music. Before leaving Melbourne, he deposited in a bank a parcel that contained an essay and photographs related to his sex life, not to be opened until 10 years after his death.

Last years
By 1957 Grainger's physical health had markedly declined, as had his powers of concentration. Nevertheless, he continued to visit Britain regularly; in May of that year he made his only television appearance, in a BBC "Concert Hour" programme when he played "Handel in the Strand" on the piano. Back home, after further surgery he recovered sufficiently to undertake a modest winter concerts season. On his 1958 visit to England he met Benjamin Britten, the two having previously maintained a mutually complimentary correspondence. He agreed to visit Britten's Aldeburgh Festival in 1959, but was prevented by illness. Sensing that death was drawing near, he made a new will, bequeathing his skeleton "for preservation and possible display in the Grainger Museum". This wish was not carried out.

Through the winter of 1959–60 Grainger continued to perform his own music, often covering long distances by bus or train; he would not travel by air. On 29 April 1960 he gave his last public concert, at Dartmouth College in Hanover, New Hampshire, although by now his illness was affecting his concentration. On this occasion his morning recital went well, but his conducting in the afternoon was, in his own words, "a fiasco". Subsequently confined to his home, he continued to revise his music and arrange that of others; in August he informed Elsie that he was working on an adaptation of one of Cyril Scott's early songs. His last letters, written from hospital in December 1960 and January 1961, record attempts to work, despite failing eyesight and hallucinations: "I have been trying to write score for several days. But I have not succeeded yet."

Grainger died in the White Plains hospital on 20 February 1961, at the age of 78. His remains were buried in the Aldridge family vault in the West Terrace Cemetery, alongside Rose's ashes. Ella survived him by 18 years; in 1972, aged 83, she married a young archivist, Stewart Manville. She died at White Plains on 17 July 1979.

Music
Grainger's own works fall into two categories: original compositions and folk music arrangements. Besides these, he wrote many settings of other composers' works. Despite his conservatory training, he rebelled against the disciplines of the central European tradition, largely rejecting conventional forms such as symphony, sonata, concerto, and opera. With few exceptions, his original compositions are miniatures, lasting between two and eight minutes. Only a few of his works originated as piano pieces, though in due course almost all of them were, in his phrase, "dished up" in piano versions.

The conductor John Eliot Gardiner describes Grainger as "a true original in terms of orchestration and imaginative instrumentation", whose terseness of expression is reminiscent in style both of the 20th-century Second Viennese School and the Italian madrigalists of the 16th and 17th centuries. Malcolm Gillies, a Grainger scholar, writes of Grainger's style that "you know it is 'Grainger' when you have heard about one second of a piece". The music's most individual characteristic, Gillies argues, is its texture – "the weft of the fabric", according to Grainger. Different textures are defined by Grainger as "smooth", "grained" and "prickly".

Grainger was a musical democrat; he believed that in a performance each player's role should be of equal importance. His elastic scoring technique was developed to enable groups of all sizes and combinations of instruments to give effective performances of his music. Experimentation is evident in Grainger's earliest works; irregular rhythms based on rapid changes of time signature were employed in Love Verses from "The Song of Solomon" (1899), and Train Music (1901), long before Stravinsky adopted this practice. In search of specific sounds Grainger employed unconventional instruments and techniques: solovoxes, theremins, marimbas, musical glasses, harmoniums, banjos, and ukuleles. In one early concert of folk music, Quilter and Scott were conscripted as performers, to whistle various parts. In "Random Round" (1912–14), inspired by the communal music-making he had heard in the Pacific Islands on his second Australasian tour, Grainger introduced an element of chance into performances; individual vocalists and instrumentalists could make random choices from a menu of variations. This experiment in aleatoric composition presaged by many decades the use of similar procedures by avant-garde composers such as Berio and Stockhausen.

The brief "Sea Song" of 1907 was an early attempt by Grainger to write "beatless" music. This work, initially set over 14 irregular bars and occupying about 15 seconds of performing time, was a forerunner of Grainger's free-music experiments of the 1930s. Grainger wrote: "It seems to me absurd to live in an age of flying, and yet not be able to execute tonal glides and curves." The idea of tonal freedom, he said, had been in his head since as a boy of eleven or twelve he had observed the wave-movements in the sea. "Out in nature we hear all kinds of lovely and touching "free" (non-harmonic) combinations of tones; yet we are unable to take up these beauties… into the art of music because of our archaic notions of harmony." In a 1941 letter to Scott, Grainger acknowledged that he had failed to produce any large-scale works in the manner of a Bach oratorio, a Wagner opera, or a Brahms symphony, but excused this failure on the grounds that all his works before the mid-1930s had been mere preparations for his free music.

As a student, Grainger had learned to appreciate the music of Grieg and came to regard the Norwegian as a paragon of Nordic beauty and greatness. Grieg in turn described Grainger as a new way forward for English composition, "quite different from Elgar, very original". After a lifetime interpreting Grieg's works, in 1944 Grainger began adapting the Norwegian's E minor Piano Sonata, Op. 7 as a "Grieg-Grainger Symphony", but abandoned the project after writing 16 bars of music. By this time, Grainger acknowledged that he had not fulfilled Grieg's high expectations of him, either as a composer or as a pianist. He also reflected on whether it would have been better, from the point of view of his development as a composer, had he never met the Griegs, "sweet and dear though they were to me".

Grainger was known for his musical experimentation and did not hesitate to exploit the capabilities of the orchestra. One early ambitious work was The Warriors (1913), an 18-minute orchestral piece, subtitled "Music to an Imaginary Ballet", which he dedicated to Delius. The music, which mixes elements of other Grainger works with references to Arnold Bax, Arnold Schoenberg and Richard Strauss, requires a huge orchestral ensemble alongside at least three pianos – in one performance, Grainger used nineteen pianos with thirty pianists – to be played by "exceptionally strong vigorous players". Critics were undecided as to whether the work was "magnificent", or merely "a magnificent failure".

Legacy
Grainger considered himself an Australian composer who, he said, wrote music "in the hopes of bringing honor and fame to my native land". However, much of Grainger's working life was spent elsewhere, and the extent to which he influenced Australian music, within his lifetime and thereafter, is debatable. His efforts to educate the Australian musical public in the mid-1930s were indifferently received, and did not attract disciples; writing in 2010, the academic and critic Roger Covell identifies only one significant contemporary Australian musician – the English-born horn player, pianist and conductor David Stanhope – working in the Grainger idiom. In 1956, the suggestion by the composer Keith Humble that Grainger be invited to write music for the opening of the 1956 Summer Olympics in Melbourne was rejected by the organisers of the Games. A "Percy Grainger Festival" was held in London in 1970, organised by Australian expatriates Bryan Fairfax and William McKie and supported financially by the Australian government.

Grainger was a life-long atheist and believed he would only endure in the body of work he left behind. To assist that survival he established the Grainger Museum in Melbourne, which was given little attention before the mid-1970s; it was initially regarded as evidence either of an over-large ego or of extreme eccentricity. Since then the University of Melbourne's commitment to the museum has, Covell asserts, "rescued [it] permanently from academic denigration and belittlement". Its vast quantities of materials have been used to investigate not only Grainger's life and works, but those of contemporaries whom Grainger had known: Grieg, Delius, Scott, and others. The Grainger home at 7 Cromwell Place, White Plains, New York, is now the Percy Grainger Library and is a further repository of memorabilia and historic performance material, open to researchers and visitors.

In Britain, Grainger's main legacy is the revival of interest in folk music. His pioneering work in the recording and setting of folk songs greatly influenced the following generation of English composers; Benjamin Britten acknowledged the Australian as his master in this respect. After hearing a broadcast of some Grainger settings, Britten declared that these "[knocked] all the Vaughan Williams and R. O. Morris arrangements into a cocked hat". In the United States, Grainger left a strong educational legacy through his involvement, over 40 years, with high school, summer school and college students. Likewise, his innovative approaches to instrumentation and scoring have left their mark on modern American band music; Timothy Reynish, a conductor and teacher of band music in Europe and America, has described him as "the only composer of stature to consider military bands the equal, if not the superior, in expressive potential to symphony orchestras." Grainger's attempts to produce "free music" by mechanical and later electronic means, which he considered his most important work, produced no follow-up; they were quickly overtaken and nullified by new technological advances. Covell nevertheless remarks that in this endeavour, Grainger's dogged resourcefulness and ingenious use of available materials demonstrate a particularly Australian aspect of the composer's character – one of which Grainger would have been proud.

Assessment

In 1945, Grainger devised an informal ratings system for composers and musical styles, based on criteria that included originality, complexity and beauty. Of 40 composers and styles, he ranked himself equal ninth – behind Wagner and Delius, but well ahead of Grieg and Tchaikovsky. Nevertheless, in his later years he frequently denigrated his career, for example writing to Scott: "I have never been a true musician or true artist". His failure to be recognised as a composer for anything beyond his popular folk-song arrangements was a source of frustration and disappointment; for years after his death the bulk of his output remained largely unperformed. From the 1990s, an increase in the number of Grainger recordings has brought a revival of interest in his works, and has enhanced his reputation as a composer. An unsigned tribute published on the Gramophone website in February 2011 to commemorate the 50th anniversary of Grainger's death opined that "though he would never be put on a pedestal to join the pantheon of immortals, he is unorthodox, original and deserves better than to be dismissed by the more snooty arbiters of musical taste".

Of Grainger the pianist, The New York Times critic Harold C. Schonberg wrote that his unique style was expressed with "amazing skill, personality and vigor". The early enthusiasm which had greeted his concert appearances became muted in later years, and reviews of his performances during the final ten years of his life were often harsh. However, Britten regarded Grainger's late recording of the Grieg concerto, from a live performance at Aarhus in 1957, as "one of the noblest ever committed to record" – despite the suppression of the disc for many years, because of the proliferation of wrong notes and other faults. Brian Allison from the Grainger Museum, referring to Grainger's early displays of artistic skills, has speculated that had John Grainger's influence not been removed, "Percy Aldridge Grainger may today be remembered as one of Australia's leading painters and designers, who just happened to have a latent talent as a pianist and composer". The ethnomusicologist John Blacking, while acknowledging Grainger's contribution to social and cultural aspects of music, nevertheless writes that if the continental foundation of Grainger's musical education had not been "undermined by dilettantism and the disastrous influence of his mother, I am sure that his ultimate contribution to the world of music would have been much greater".

Recordings
Between 1908 and 1957 Grainger made numerous recordings, usually as pianist or conductor, of his own and other composers' music. His first recordings, for The Gramophone Company Ltd (later HMV), included the cadenza to Grieg's piano concerto; he did not record a complete version of this work on disc until 1945. Much of his recording work was done between 1917 and 1931, under contract with Columbia. At other times he recorded for Decca (1944–45 and 1957), and Vanguard (1957). Of his own compositions and arrangements, "Country Gardens", "Shepherd's Hey" and "Molly on the Shore" and "Lincolnshire Posy" were recorded most frequently; in recordings of other composers, piano works by Bach, Brahms, Chopin, Grieg, Liszt and Schumann figure most often. Grainger's complete 78 rpm solo piano recordings are now available on compact disc as a CD box set.

During his association with the Duo-Art company between 1915 and 1932, Grainger made around 80 piano rolls of his own and others' music using a wooden robot designed to play a concert grand piano via an array of precision mechanical fingers and feet; replayings of many of these rolls have subsequently been recorded on to compact disc (CD). This reproduction system allowed Grainger to make a posthumous appearance in the Albert Hall, London, during the 1988 last night of the Proms as soloist with the BBC Symphony Orchestra in Grieg's Piano Concerto.

Since Grainger's death, recordings of his works have been undertaken by many artists and issued under many different labels. In 1995, Chandos Records began to compile a complete recorded edition of Grainger's original compositions and folk settings. Of 25 anticipated volumes, 19 had been completed as of 2010; these were issued as a CD boxed set in 2011, to mark the 50th anniversary of the composer's death. A reissue of this along with two extra CDs was released in January 2021 to mark the 60th anniversary of the composer's death.

Notes and references
Notes

References

title: Percy Grainger


text:
Talk:Percy Grainger

Short tutorial on misplaced modifiers
Of late the rare Wikipedia editor has been reverting corrections I have made of misplaced modifiers, without showing any understanding of what the error means and appealing to an authority called Fowler (absent from my bookshelf) who apparently condones it. This appeal strikes me as akin to expecting others to let their shirttail hang out over their trousers because some etiquette authority said it might be done. That permission doesn't oblige one to do it, if one sees a reason not to. Because sometimes, as in the example below, misplaced modifiers create confusion, and because they can always be gracefully averted, I find it sensible to do so.

What is the intended meaning of this sentence, taken from a manufacturer's manual:

Only install refrigerant lines outdoors in dry weather.

Any of five meanings could be drawn from it, depending on what the reader considers only to be modifying. If you can't see what these meanings are, the example will be lost on you.

You may say “It doesn’t matter! You could figure it out from the context!”

Sometimes you can...and if there is context. But why should anyone have to “figure out from the context” what a competent writer can easily express with unequivocal and graceful clarity, irrespective of context? Is the job of a writer and editor to make readers work harder than they would need to work if (s)he took the trouble to write clearly?

Please consider also that there may be readers whose first language is not English and whose understanding depends on literal translation. Literal translation of idioms, semantic or syntactic, doesn’t work well. If you don’t know any foreign languages and have never labored to translate idiomatic phrases like il n'a qu'une verbe, this proposition will be lost on you.

When we place a modifier directly before the term it's intended to modify and not before terms it isn't, the meaning is clear. In this case, the writer wished to say, and should have said, Install refrigerant lines outdoors only in dry weather.

A final note on edit wars: they take two to fight: an editor and a reverter. One who tucks in the shirttail and one who yanks it out again. Chenopodiaceous (talk) 00:08, 12 February 2022 (UTC)

Grainger’s students included Viola van Katwijk
This information was removed from the main article: Grainger’s students included American composer and pianist Viola Van Katwijk. (source: Anderson, Ruth (1976). Contemporary American composers : a biographical dictionary. Boston: G.K. Hall. p. 449. ISBN  0-8161-1117-0 . OCLC 2035024.).

T. E. Meeks (talk) 23:08, 16 April 2023 (UTC)
 * He had a number of students. Why do you feel this one in particular should be called out? Nikkimaria (talk) 03:00, 17 April 2023 (UTC)
 * Grainger did not find Viola Van Katwijk important enough to mention in his autobiography, and she is not mentioned in the books about Grainger by Lewis Foreman, Malcolm Gillies, Wilfrid Mellers, John Bird and Eileen Dorum. If she doesn't merit a mention in those full-length books, how much more disproportionate it would be to single her out for a mention in our 7,000-word article.  Tim riley  talk   08:56, 17 April 2023 (UTC)

"Nineteen pianos with thirty pianists"?
Can anyone verify the claim that Grainger once "used nineteen pianos with thirty pianists" in a performance of "The Warriors"? The reference pdf (a Chandos notes booklet) seems only to be available on purchase. | A 1982 recording/documentary (?) of Grainger's Biographer John Bird makes this claim not of Warriors, but of "Lord Peter's Stable Boy". It's unlikely that these exact numbers would have been assembled on two separate occasions, so unless this was in fact the same performance, something seems off. Noahfgodard (talk) 23:21, 3 February 2024 (UTC)
 * Update: I was able to find the booklet through my university library, and it seems this was the same performance after all – the notes say 1929 and Bird says 1930, but both claim the concert took place in the Chicago opera house. Bird himself says "...I think...", so it's fair to say the discrepancy of years was a simple mistake on his part. In any case, I think we can disregard my above concern. Apologies! Noahfgodard (talk) 23:32, 3 February 2024 (UTC)

List of Works in infobox
Many articles link the List of Works article in the infobox. See Beethoven, Mozart, Shostakovitch, Stravinsky. Why should Grainger be different? I did revert a revertion, which is bad form, but the original revert says "Breach of MOS". Which MOS? How is it a breach? Are we to remove all those other lists? — Iadmc  ♫ talk  02:54, 12 June 2024 (UTC)
 * You know which breach. The disruptive editor at your talk page has told you which one. - SchroCat (talk) 12:53, 12 June 2024 (UTC)
 * I really don't. Gerda says I haven't breached MOS. And stop with the accusations like "disruptive editor". Would a list of his most notable works be OK? — Iadmc  ♫ talk  13:11, 12 June 2024 (UTC)
 * She would. There's no accusation, just a description, and an accurate one. Yes, that would be fine. - 14:20, 12 June 2024 (UTC)
 * Will do— Iadmc  ♫ talk  14:21, 12 June 2024 (UTC)
 * But who chooses what is "notable"? One person's selection is hardly encyclopaedic.  Tim riley  talk   15:24, 12 June 2024 (UTC)
 * It's insane to me how anyone in good faith could say such a thing and claim it's 'not an accusation'. I'd make an accusation of my own here, but that would be a personal attack. ♫ Melodia Chaconne ♫ (talk) 07:03, 13 June 2024 (UTC)
 * Thanks for trying to stir the pot, but maybe letting sleeping dogs lie would have been a better pathway? - SchroCat (talk) 07:25, 13 June 2024 (UTC)
 * @SchroCat I still would like to know how adding a link to List of Works breaches a Manual of Style. Which one? Music? Infobox? General? A quote would be helpful. Thanks — Iadmc  ♫ talk  08:00, 13 June 2024 (UTC)

title: Talk:Percy Grainger


text:
Galvanic cell

A galvanic cell or voltaic cell, named after the scientists Luigi Galvani and Alessandro Volta, respectively, is an electrochemical cell in which an electric current is generated from spontaneous oxidation–reduction reactions. A common apparatus generally consists of two different metals, each immersed in separate beakers containing their respective metal ions in solution that are connected by a salt bridge or separated by a porous membrane.

Volta was the inventor of the voltaic pile, the first electrical battery. Common usage of the word battery has evolved to include a single Galvanic cell, but the first batteries had many Galvanic cells.

History
In 1780, Luigi Galvani discovered that when two different metals (e.g., copper and zinc) are in contact and then both are touched at the same time to two different parts of a muscle of a frog leg, to close the circuit, the frog's leg contracts. He called this "animal electricity". The frog's leg, as well as being a detector of electrical current, was also the electrolyte (to use the language of modern chemistry).

A year after Galvani published his work (1790), Alessandro Volta showed that the frog was not necessary, using instead a force-based detector and brine-soaked paper (as electrolyte). (Earlier Volta had established the law of capacitance C = $Q⁄V$ with force-based detectors). In 1799 Volta invented the voltaic pile, which is a stack of galvanic cells each consisting of a metal disk, an electrolyte layer, and a disk of a different metal. He built it entirely out of non-biological material to challenge Galvani's (and the later experimenter Leopoldo Nobili)'s animal electricity theory in favor of his own metal-metal contact electricity theory. Carlo Matteucci in his turn constructed a battery entirely out of biological material in answer to Volta. Volta's contact electricity view characterized each electrode with a number that we would now call the work function of the electrode. This view ignored the chemical reactions at the electrode-electrolyte interfaces, which include H2 formation on the more noble metal in Volta's pile.

Although Volta did not understand the operation of the battery or the galvanic cell, these discoveries paved the way for electrical batteries; Volta's cell was named an IEEE Milestone in 1999.

Some forty years later, Faraday (see Faraday's laws of electrolysis) showed that the galvanic cell—now often called a voltaic cell—was chemical in nature. Faraday introduced new terminology to the language of chemistry: electrode (cathode and anode), electrolyte, and ion (cation and anion). Thus Galvani incorrectly thought the source of electricity (or source of electromotive force (emf), or seat of emf) was in the animal, Volta incorrectly thought it was in the physical properties of the isolated electrodes, but Faraday correctly identified the source of emf as the chemical reactions at the two electrode-electrolyte interfaces. The authoritative work on the intellectual history of the voltaic cell remains that by Ostwald.

It was suggested by Wilhelm König in 1940 that the object known as the Baghdad battery might represent galvanic cell technology from ancient Parthia. Replicas filled with citric acid or grape juice have been shown to produce a voltage. However, it is far from certain that this was its purpose—other scholars have pointed out that it is very similar to vessels known to have been used for storing parchment scrolls.

Principles

Galvanic cells are extensions of spontaneous redox reactions, but have been merely designed to harness the energy produced from said reaction. For example, when one immerses a strip of zinc metal (Zn) in an aqueous solution of copper sulfate (CuSO4), dark-colored solid deposits will collect on the surface of the zinc metal and the blue color characteristic of the Cu2+ ion disappears from the solution. The depositions on the surface of the zinc metal consist of copper metal, and the solution now contains zinc ions. This reaction is represented by

 * Zn (s) + Cu2+ (aq) → Zn2+ (aq) + Cu (s)

In this redox reaction, Zn is oxidized to Zn2+ and Cu2+ is reduced to Cu. When electrons are transferred directly from Zn to Cu2+, the enthalpy of reaction is lost to the surroundings as heat. However, the same reaction can be carried out in a galvanic cell, allowing some of the chemical energy released to be converted into electrical energy. In its simplest form, a half-cell consists of a solid metal (called an electrode) that is submerged in a solution; the solution contains cations (+) of the electrode metal and anions (−) to balance the charge of the cations. The full cell consists of two half-cells, usually connected by a semi-permeable membrane or by a salt bridge that prevents the ions of the more noble metal from plating out at the other electrode.

A specific example is the Daniell cell (see figure), with a zinc (Zn) half-cell containing a solution of ZnSO4 (zinc sulfate) and a copper (Cu) half-cell containing a solution of CuSO4 (copper sulfate). A salt bridge is used here to complete the electric circuit.

If an external electrical conductor connects the copper and zinc electrodes, zinc from the zinc electrode dissolves into the solution as Zn2+ ions (oxidation), releasing electrons that enter the external conductor. To compensate for the increased zinc ion concentration, via the salt bridge zinc ions (cations) leave and sulfate ions (anions) enter the zinc half-cell. In the copper half-cell, the copper ions plate onto the copper electrode (reduction), taking up electrons that leave the external conductor. Since the Cu2+ ions (cations) plate onto the copper electrode, the latter is called the cathode. Correspondingly the zinc electrode is the anode. The electrochemical reaction is

This is the same reaction as given in the previous example. In addition, electrons flow through the external conductor, which is the primary application of the galvanic cell.

As discussed under cell voltage, the electromotive force of the cell is the difference of the half-cell potentials, a measure of the relative ease of dissolution of the two electrodes into the electrolyte. The emf depends on both the electrodes and on the electrolyte, an indication that the emf is chemical in nature.

Half reactions and conventions
A half-cell contains a metal in two oxidation states. Inside an isolated half-cell, there is an oxidation-reduction (redox) reaction that is in chemical equilibrium, a condition written symbolically as follows (here, "M" represents a metal cation, an atom that has a charge imbalance due to the loss of "n" electrons):

 * Mn+ (oxidized species) + ne− M (reduced species)

A galvanic cell consists of two half-cells, such that the electrode of one half-cell is composed of metal A, and the electrode of the other half-cell is composed of metal B; the redox reactions for the two separate half-cells are thus:

 * An+ + ne− A
 * Bm+ + me− B

The overall balanced reaction is:

 * m A + n Bm+ n B + m An+

In other words, the metal atoms of one half-cell are oxidized while the metal cations of the other half-cell are reduced. By separating the metals in two half-cells, their reaction can be controlled in a way that forces transfer of electrons through the external circuit where they can do useful work.

 * The electrodes are connected with a metal wire in order to conduct the electrons that participate in the reaction.

 * In one half-cell, dissolved metal-B cations combine with the free electrons that are available at the interface between the solution and the metal-B electrode; these cations are thereby neutralized, causing them to precipitate from solution as deposits on the metal-B electrode, a process known as plating.
 * This reduction reaction causes the free electrons throughout the metal-B electrode, the wire, and the metal-A electrode to be pulled into the metal-B electrode. Consequently, electrons are wrestled away from some of the atoms of the metal-A electrode, as though the metal-B cations were reacting directly with them; those metal-A atoms become cations that dissolve into the surrounding solution.
 * As this reaction continues, the half-cell with the metal-A electrode develops a positively charged solution (because the metal-A cations dissolve into it), while the other half-cell develops a negatively charged solution (because the metal-B cations precipitate out of it, leaving behind the anions); unabated, this imbalance in charge would stop the reaction. The solutions of the half-cells are connected by a salt bridge or a porous plate that allows ions to pass from one solution to the other, which balances the charges of the solutions and allows the reaction to continue.

By definition:

 * The anode is the electrode where oxidation (loss of electrons) takes place (metal-A electrode); in a galvanic cell, it is the negative electrode, because when oxidation occurs, electrons are left behind on the electrode. These electrons then flow through the external circuit to the cathode (positive electrode) (while in electrolysis, an electric current drives electron flow in the opposite direction and the anode is the positive electrode).
 * The cathode is the electrode where reduction (gain of electrons) takes place (metal-B electrode); in a galvanic cell, it is the positive electrode, as ions get reduced by taking up electrons from the electrode and plate out (while in electrolysis, the cathode is the negative terminal and attracts positive ions from the solution). In both cases, the statement 'the cat hode attracts cat ions' is true.

Galvanic cells, by their nature, produce direct current.

The Weston cell has an anode composed of cadmium mercury amalgam, and a cathode composed of pure mercury. The electrolyte is a (saturated) solution of cadmium sulfate. The depolarizer is a paste of mercurous sulfate. When the electrolyte solution is saturated, the voltage of the cell is very reproducible; hence, in 1911, it was adopted as an international standard for voltage.

A battery is a set of galvanic cells that are connected together to form a single source of voltage. For instance, a typical 12V lead–acid battery has six galvanic cells connected in series with the anodes composed of lead and cathodes composed of lead dioxide, both immersed in sulfuric acid. Large battery rooms, for instance in a telephone exchange providing central office power to user's telephones, may have cells connected in both series and parallel.

Cell voltage
The voltage (electromotive force Eo) produced by a galvanic cell can be estimated from the standard Gibbs free energy change in the electrochemical reaction according to:

$$E_\text{cell}^o =- \Delta_r G^o/(\nu_e F ) $$

where νe is the number of electrons transferred in the balanced half reactions, and F is Faraday's constant. However, it can be determined more conveniently by the use of a standard potential table for the two half cells involved. The first step is to identify the two metals and their ions reacting in the cell. Then one looks up the standard electrode potential, Eo, in volts, for each of the two half reactions. The standard potential of the cell is equal to the more positive Eo value minus the more negative Eo value.

For example, in the figure above the solutions are CuSO4 and ZnSO4. Each solution has a corresponding metal strip in it, and a salt bridge or porous disk connecting the two solutions and allowing ions to flow freely between the copper and zinc solutions. To calculate the standard potential one looks up copper and zinc's half reactions and finds:

 * Cu2+ + 2  Cu  Eo = +0.34 V
 * Zn2+ + 2  Zn  Eo = −0.76 V

Thus the overall reaction is:

 * Cu2+ + Zn Cu + Zn2+

The standard potential for the reaction is then +0.34 V − (−0.76 V) = 1.10 V. The polarity of the cell is determined as follows. Zinc metal is more strongly reducing than copper metal because the standard (reduction) potential for zinc is more negative than that of copper. Thus, zinc metal will lose electrons to copper ions and develop a positive electrical charge. The equilibrium constant, K, for the cell is given by:

$$\ln K= \frac{\nu_e FE_\text{cell}^o}{RT}$$

where F is the Faraday constant, R is the gas constant and T is the temperature in kelvins. For the Daniell cell K is approximately equal to $15,000,000,000,000,000,000,000,000,000,000,000,000$. Thus, at equilibrium, a few electrons are transferred, enough to cause the electrodes to be charged.

Actual half-cell potentials must be calculated by using the Nernst equation as the solutes are unlikely to be in their standard states:

$$E_{\text{half-cell}} = E^o - \frac{RT}{\nu_e F}\ln_e Q $$

where Q is the reaction quotient. When the charges of the ions in the reaction are equal, this simplifies to:

$$E_{\text{half-cell}} = E^o - 2.303 \frac{RT}{\nu_e F} \log_{10} \left\{ \text{M}^{n+}\right\}$$

where {Mn+} is the activity of the metal ion in solution. In practice concentration in mol/L is used in place of activity. The metal electrode is in its standard state so by definition has unit activity. The potential of the whole cell is obtained as the difference between the potentials for the two half-cells, so it depends on the concentrations of both dissolved metal ions. If the concentrations are the same, $$E_\text{cell} = E_\text{cell}^o $$and the Nernst equation is not needed under the conditions assumed here.

The value of 2.303$R⁄F$ is $0 V/K$, so at 25 °C (298.15 K) the half-cell potential will change by only 0.05918 V/νe if the concentration of a metal ion is increased or decreased by a factor of 10.

$$E_{\text{half-cell}}= E^o - \frac{0.05918\ \text{V}}{\nu_e} \log_{10} \left[ \text{M}^{n+}\right]$$

These calculations are based on the assumption that all chemical reactions are in equilibrium. When a current flows in the circuit, equilibrium conditions are not achieved and the cell voltage will usually be reduced by various mechanisms, such as the development of overpotentials. Also, since chemical reactions occur when the cell is producing power, the electrolyte concentrations change and the cell voltage is reduced. A consequence of the temperature dependency of standard potentials is that the voltage produced by a galvanic cell is also temperature dependent.

Galvanic corrosion
Galvanic corrosion is the electrochemical erosion of metals. Corrosion occurs when two dissimilar metals are in contact with each other in the presence of an electrolyte, such as salt water. This forms a galvanic cell, with hydrogen gas forming on the more noble (less active) metal. The resulting electrochemical potential then develops an electric current that electrolytically dissolves the less noble material. A concentration cell can be formed if the same metal is exposed to two different concentrations of electrolyte.

Types

 * Concentration cell
 * Electrolytic cell
 * Electrochemical cell
 * Lemon battery
 * Thermogalvanic cell

title: Galvanic cell


text:
OMC

OMC may refer to:

Business

 * Oil marketing company

Organizations

 * Odisha Mining Corporation, a state-owned mining company in Odisha, India
 * OMC Shipping pte. ltd., a large bulk carrier, container and PCTC shipping company based in Singapore
 * Omnicom Group (stock symbol)
 * Outboard Marine Corporation
 * Olifant Manufacturing Company of South Africa, now known as Land Systems OMC
 * Acronym for the World Trade Organization in French, Portuguese and Spanish
 * Osaka Medical College
 * Oxfordshire Museums Council

Places

 * Ormoc Airport in Ormoc City, Leyte, the Philippines

Musical groups

 * OMC (band), a New Zealand music group formerly known as Otara Millionaires Club
 * Old Man's Child, a Norwegian Black metal band

Technology

 * Operations and Maintenance Centre, a controlling equipment for telecom networks
 * Orange Monte Carlo, Android phone

Other

 * Octyl methoxycinnamate, the active ingredient in sunscreens
 * Open Method of Coordination, a means of governance in the European Union
 * Ontario Medal for Good Citizenship
 * Order of Cultural Merit
 * "Ordinary muon capture"
 * Outlaw motorcycle club

title: OMC