Paul Callaway joined two great choral works, one from the 19th and one from the 20th century yesterday afternoon in what proved an event of contrasting beauties offered by the Cathedral Choral Society.

A large audience in Washington Cathedral heard the Poulenc "Gloria," music not yet two decades old, which has already become one of the staples of fine choral groups, and the Brahms Requiem, now comfortably into its second hundred years.

The large chorus sounded better than it has in some years, thanks especially to an infusion of younger voices, notably in the tenor section, for which special praise is due. Callaway found ideal approaches to the divergent works through flawless tempos and the wide dynamic ranges possible in both.

It is not often that a chorus must make the shift in mood involved in going from the offbeat brilliance of Poulenc to the solid sobriety of Brahms.It is to the singers' credit that their entire approach, in tone as well as in style, made the change with fine effect.

Both works call for a soprano soloist of the utmost finesse and sensitivity. It was probable that no singer since Adele Addison, who first floated the exquisite soprano lines of the Poulenc, to the composer's vast delight, has matched Phyllis Bryn-Julson's radiant high soft notes of yesterday, or her musicianly phrasing in both Poulenc and the single, famous solo allotted to her in the Brahms.

Richard Dirksen was the baritone in the Brahms, singing with the intimate manner suggested in his opening lines, "Lord, make me to know the number of my days, and how frail I am." It, too, was singing highly musical in impulse.

Callaway gave his singers expert support with members of the National Symphony and friends, and the invaluable addition of the cathedral organ, an instrument Brahms marks "optional," but which yesterday was a distinct adornment.