of a composer an orchestra always presents itself as a combination of four groups of instruments—­choirs, let us call them, with unwilling apology to the lexicographers.  These choirs are:  first, the viols of four sorts—­violins, violas, violoncellos, and double-basses, spoken of collectively as the “string quartet;” second, the wind instruments of wood (the “wood-winds” in the musician’s jargon)—­flutes, oboes, clarinets, and bassoons; third, the wind instruments of brass (the “brass")—­trumpets, horns, trombones, and bass tuba.  In all of these subdivisions there are numerous variations which need not detain us now.  A further subdivision might be made in each with reference to the harmony voices (showing an analogy with the four voices of a vocal choir—­soprano, contralto, tenor, and bass); but to go into this might make the exposition confusing.  The fourth “choir” (here the apology to the lexicographers must be repeated with much humility and earnestness) consists of the instruments of percussion—­the kettle-drums, big drum, cymbals, triangle, bell chime, etc. (sometimes spoken of collectively in the United States as “the battery").

[Illustration:  SEATING PLAN OF THE NEW YORK PHILHARMONIC SOCIETY.]

[Sidenote:  How orchestras are seated.]

[Sidenote:  Plan of the New York Philharmonic.]

The disposition of these instruments in our orchestras is largely a matter of individual taste and judgment in the conductor, though the general rule is exemplified in the plan given herewith, showing how Mr. Anton Seidl has arranged the desks for the concerts of the Philharmonic Society of New York.  Mr. Theodore Thomas’s arrangement differed very little from that of Mr. Seidl, the most noticeable difference being that he placed the viola-players beside the second violinists, where Mr. Seidl has the violoncellists.  Mr. Seidl’s purpose in making the change was to gain an increase in sonority for the viola part, the position to the right of the stage (the left of the audience) enabling the viola-players to hold their instruments with the F-holes toward the listeners instead of away from them.  The relative positions of the harmonious battalions, as a rule, are as shown in the diagram.  In the foreground, the violins, violas, and ’cellos; in the middle distance, the wood-winds; in the background, the brass and the battery; the double-basses flanking the whole body.  This distribution of forces is dictated by considerations of sonority, the most assertive instruments—­the brass and drums—­being placed farthest from the hearers, and the instruments of the viol tribe, which are the real backbone of the band and make their effect by a massing of voices in each part, having the place of honor and greatest advantage.  Of course it is understood that I am speaking of a concert orchestra.  In the case of theatrical or operatic bands the arrangement of the forces is dependent largely upon the exigencies of space.