MUSICAL COMPOSITION

. COLOUR 103Composers will learn the best way to use the horns ina score by writing first with the cramped series ofnotes of the natural horn, and making up for itsdeficiencies by ingenuity of treatment, and even byinventing subjects which will minimise them. Whenhe advances to writing with valve-horns he will notoverstep the limits of true horn quality even in themost complex passages. The instruments he willbegin by using are :Wood.Brass. {Percussion.String.. 11 or 2 Flutes.2 Oboes.2 Clarinets.2 Bassoons.2 Horns.2 Trumpets.2 Kettle Drums.Violins (divided into firsts and seconds).Violas.Violoncellos.Double Basses.Then as to the general principles of orchestraldesign. He will layout the treatment on the lines ofthree parts and not four; for a study of Mozart willshow that he distributes his parts in threes or multiplesof three, a principle which Wagner elaborated in hislater works by tripling each branch of the wood-windfamily. This division of three applies to the contrastsand combinations of wood, brass and strings as well asto the general lie of the music itself. It is the truebasis of all good instrumentation. Four-part treatmentthere will be, and plenty of it, but in a secondaryposition to three-part. For example, Mozart will moreoften group his strings thus: