<P> The development of the valve horn was exploited by romantic composers such as Bruckner, Mahler, and Richard Strauss, whose father was a well - known professional horn player . Strauss's Till Eulenspiegel's Merry Pranks contains one of the best known horn solos from this period, relying on the chromatic facility of the valved horn . Schumann's Konzertstück for four horns and orchestra is a notable three - movement work . Brahms had a lifelong love - affair with the instrument, with many prominently featured parts throughout his four symphonies . However players today typically play Brahms on modern valved instruments . </P> <P> There is an abundance of chamber music repertoire for horn . It is a standard member of the wind quintet and brass quintet, and often appears in other configurations, such as Brahms' Horn Trio for violin, horn and piano (for which, however, Brahms specified the natural horn). Also, the horn can be used by itself in a horn ensemble or "horn choir". The horn choir is especially practical because the extended range of the horn provides the composer or arranger with more possibilities, registerally, sonically, and contrapuntally . </P> <P> A classical orchestra usually contained two horns . Typically, the 1st horn played a high part and the 2nd horn played a low part . Composers from Beethoven onwards commonly used four horns . Here, the 1st and 2nd horns played as a pair (1st horn being high, 2nd horn being low), and the 3rd and 4th horns played as another pair (3rd horn being high, 4th horn being low). Music written for the modern horn follows a similar pattern with 1st and 3rd horns being high and 2nd and 4th horns being low . This configuration serves multiple purposes . It is easier to play high when the adjacent player is playing low and vice versa . Pairing makes it easier to write for horns, as the 3rd and 4th horns can take over from the 1st and 2nd horns or play contrasting material . For example, if the piece is in C minor, the 1st and 2nd horns might be in C, the tonic major key, which could get most of the notes, and the 3rd and 4th horns might be in E ♭, the relative major key, to fill in the gaps . Many orchestral horn sections today also have an assistant who doubles the 1st horn part for selected passages, joining in loud parts, playing instead of the principal if there is a 1st horn solo approaching, or alternating with the principal if the part is tiring to play . Often the assistant is asked to play a passage after resting a long time . Also, he or she may be asked to enter in the middle of a passage, exactly matching the sound, articulation, and overall interpretation of the principal . </P> <P> The horn has rarely been used in jazz music; colloquially in jazz, the word "horn" refers to any wind instrument . Notable exponents, however, include composer / arranger Gil Evans who included the horn as an ensemble instrument from the 1940s, first in Claude Thornhill's groups, and later with the pioneering cool jazz nonet led by trumpeter Miles Davis, and in many other projects that sometimes also featured Davis, as well as Don Ellis, a trumpet player from Stan Kenton's jazz band . Notable works of Ellis' jazz horn include "Strawberry Soup" and other songs on the album Tears of Joy . Notable improvising horn players in jazz include Julius Watkins, Willie Ruff, John Graas, David Amram, John Clark, Vincent Chancey, Mark Taylor, Giovanni Hoffer, Arkady Shilkloper, Adam Unsworth, and Tom Varner . </P>

How many french horns are there in an orchestra
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