ORGAN-PART. The music of the part to be played by the organist in an oratorio, psalm, cantata, or other sacred work. Formerly the organist sat at performance with the score before him; and from the figures attached to the bass line, with the assistance of such directions as Organo, Senza organo, Tasto solo, Unisono, etc., he constructed the organ accompaniment according to his ability; and in the case of airs it required the special training of that contrapuntal age to do it properly. Nowadays less reliance is put on the casual ability of a performer, and the composer writes out the organ-part as completely as he does that for the violin, harp, or oboe. St. Paul, the Lobgesang, and Elijah, have each their published organ-part. Mendelssohn also wrote organ-parts for Handel's Solomon and Israel in Egypt—the latter in his edition of Israel for the London 'Handel Society'—grounded on the figured-bass of the composer.
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