An orchestra is a large instrumental ensemble typical of classical music, which combines instruments from different families, including bowed string instruments such as the violin, viola and double bass, brass instruments such as the horn, trumpet and tuba, woodwinds such as the flute, oboe and bassoon, percussion instruments such as the timpani, bass drum, snare drum and mallet percussion instruments each grouped in sections. Other instruments such as the piano and celesta may sometimes appear in a fifth keyboard section or may stand alone, as may the concert harp and, for performances of some modern compositions, electronic instruments. A full-size Western orchestra may sometimes be called a symphony orchestra or philharmonic orchestra; the actual number of musicians employed in a given performance may vary from seventy to over one hundred musicians, depending on the work being played and the size of the venue. A chamber orchestra is a smaller-sized ensemble of fewer. Orchestras that specialize in the Baroque music of, for example, Johann Sebastian Bach and George Frideric Handel, or Classical repertoire, such as that of Haydn and Mozart, tend to be smaller than orchestras performing a Romantic music repertoire, such as the symphonies of Johannes Brahms.

The typical orchestra grew in size throughout the 18th and 19th centuries, reaching a peak with the large orchestras called for in the works of Richard Wagner, Gustav Mahler. Orchestras are led by a conductor who directs the performance with movements of the hands and arms made easier for the musicians to see by use of a conductor's baton; the conductor sets the tempo and shapes the sound of the ensemble. The conductor prepares the orchestra by leading rehearsals before the public concert, in which the conductor provides instructions to the musicians on their interpretation of the music being performed; the leader of the first violin section called the concertmaster plays an important role in leading the musicians. In the Baroque music era, orchestras were led by the concertmaster or by a chord-playing musician performing the basso continuo parts on a harpsichord or pipe organ, a tradition that some 20th-century and 21st-century early music ensembles continue. Orchestras play a wide range of repertoire, including symphonies and ballet overtures, concertos for solo instruments, as pit ensembles for operas and some types of musical theatre.

Amateur orchestras include those made up of students from an elementary school or a high school, youth orchestras, community orchestras. The term orchestra derives from the Greek ὀρχήστρα, the name for the area in front of a stage in ancient Greek theatre reserved for the Greek chorus; the invention of the piston and rotary valve by Heinrich Stölzel and Friedrich Blühmel, both Silesians, in 1815, was the first in a series of innovations which impacted the orchestra, including the development of modern keywork for the flute by Theobald Boehm and the innovations of Adolphe Sax in the woodwinds, notably the invention of the saxophone. These advances would lead Hector Berlioz to write a landmark book on instrumentation, the first systematic treatise on the use of instrumental sound as an expressive element of music; the next major expansion of symphonic practice came from Richard Wagner's Bayreuth orchestra, founded to accompany his musical dramas. Wagner's works for the stage were scored with unprecedented scope and complexity: indeed, his score to Das Rheingold calls for six harps.

Thus, Wagner envisioned an ever-more-demanding role for the conductor of the theatre orchestra, as he elaborated in his influential work On Conducting. This brought about a revolution in orchestral composition, set the style for orchestral performance for the next eighty years. Wagner's theories re-examined the importance of tempo, bowing of string instruments and the role of principals in the orchestra; as the early 20th century dawned, symphony orchestras were larger, better funded, better trained than before. The influence of Gustav Mahler was innovational. 8, Mahler pushes the furthest boundaries of orchestral size. By the late Romantic era, orchestras could support the most enormous forms of symphonic expression, with huge string sections, massive brass sections and an expanded range of percussion instruments. With the recording era beginning, the standards of performance were pushed to a new level, because a recorded symphony could be listened to and minor errors in intonation or ensemble, which might not be noticeable in a live performance, could be heard by critics.

As recording technologies improved over the 20th and 21st centuries small errors in a recording could be "fixed" by audio editing or overdubbing. Some older conductors and composers could remember a time when "getting through" the music as best as possible was the standard. Combined with the wider audience made possible by recording, this led to a renewed focus on particular star conductors and on a high standard of orchestral execution; the typical symphony orchestra consists of four groups of related musical instruments called the woodwinds, brass and strings. Other instruments such as the piano and celesta may sometimes be grouped into a fifth section such as a key

The School, Mount Victoria known as The School, Mt Victoria, was an independent, non-denominational, boarding school for boys, located in Mount Victoria, a small township in the Blue Mountains of New South Wales, Australia. It was located 120 kilometres via road from Sydney and 1,043 metres above sea-level. Opened on 18 July 1885, the school was designed and run by the proprietor and principal Henry Guenther Rienits. Although Rienits was a naturalized Australian citizen, he was of German birth and so was forced by war-time legislation to close The School during 1916; the campus was situated amongst ornamental gardens on eight acres. The main building contained a large schoolroom, dining hall and lavatories on the ground floor, with dormitories on the upper floor. Facilities included a swimming pool fed by rifle range, tennis court and gymnasium; the students came from the far west of the state. The School provided a commercial education with an emphasis on business and shorthand, leading to the junior certificate.

Pupils were prepared for university entry if required. By 1906, more than 600 boys had attended The School, 90 students had passed different examinations leading to tertiary study; the boys wore a uniform and there was a drum and fife band. Air Vice Marshal William Bostock CB, DSO, OBE, a senior commander in the Royal Australian Air Force Lionel Clive Ball, Chief Geologist, Geological Survey of Queensland

Rathcoran is a passage grave and hillfort and National Monument located atop Baltinglass Hill, County Wicklow, Ireland. Rathcoran is located atop Baltinglass Hill, 2 km east-northeast of Baltinglass, overlooking the River Slaney; the passage grave is thought to be contemporaneous with Newgrange, i.e. it was built 3500–3000 BC, during the Neolithic. The site was excavated in 1934–36 by P. T. Walshe, revealing evidence of the cremations of at least 3 adults and a child. Fragments of quartz unearthed during the excavation. Carbonised hazelnuts, wheat grains and a saddle quern point to the extent of local climate change: in Neolithic Ireland, the climate was drier and warmer, County Wicklow's glens were densely wooded, farmers could grow crops at altitudes above 300 m. Five hillforts surround Baltinglass. Rathcoran, atop Baltinglass Hill is dated to 1000 BC or earlier: during the Bronze Age; the name is from the Irish Ráth Cuaráin, but this name is doubtful: the original name could be Ráth Charnáin, "ringfort of the cairn."

The passage tomb survives as a multi-period kerbed cairn with a diameter of 27 m, underneath which are five structures: A kerb of large stones surround the cairn, an inner kerb was revealed during excavation. Two stones of the inner kerb and one of the outer bear passage tomb art; the main tomb is on the north side. It has a short passage, 3.2 m long, roofed with slabs and leading to a chamber 2 m in diameter which contains three shallow recesses and a stone basin with pecked ornament. On the south side of the cairn is another tomb comprising a chamber divided into three compartments, but no passage, two of its stones bear passage tomb art. On the northwest side of the cairn are the remains of a small corbelled structure overlain by the inner kerb. A fifth chamber stands inside the kerb to the east of the main tomb; the finds from the site include the cremated bones of at least three adults and one child, flint scrapers, Carrowkeel pottery and bone pins. Finds from beneath the cairn included a stone axe, a flint javelin-head, scrapers, an egg-shaped stone, carbonised wheat grains and hazelnuts.

A saddle quern was found in the cairn. The Rathcoran hillfort, a bivallate ringfort, is at the top of Baltinglass Hill, surrounds the cairn. Stones from the cairn were moved to make a protective wall, it has a double rampart and was intended to have a third, incompleted. It encloses a oval shape, around 400 m at its widest point