In comparison with the frequent instrumental concerts which we hear all through the season, choral programs are extremely rare in Cambridge. This week, however, two long concerts of vocal music will be given here. Tomorrow evening the Radcliffe Choral Society and the Radcliffe and Harvard Orchestras will perform jointly a program made up of accompanied choruses by Bach, Handel, and Dargomyzhski; works by Bach, Purcell and Beethoven for orchestra, and a group of traditional songs for chorus alone.

Though it is rather unfortunate that the Radcliffe concert and the joint Harvard-Yale Glee Club program on Friday night are spaced so closely, the two differ so greatly in spirit that they tread on each other's toes only slightly. The Yale club has always adhered to the traditional pre-Davison formula of trick pieces and "barbershop" arrangements, and Mr. Woodworth has selected music for the Harvard part of the program which is evidently intended to harmonize at least with the spirit of the Yale section without compromising the usual musical standard of the club.

The Purcell catches, for example, are neat, sparkling little pieces written to rollicking texts, which require a certain amount of editing for relatively prudish modern audiences. Lawton's arrangement of Casey Jones is a remarkably clever composition, and The Old Maid's Song, a Kentucky mountain folk-song, has a text and a lilting melody which ensure its success in spite of a rather unimaginative setting.

The annual Yale concert is about the only occasion on which the Glee Club sings this type of program in Cambridge. It is an excellent opportunity for those who have heard these singers only in joint performances of the heavier type of vocal music to see how effective they are in the smaller works where the direct human appeal of the voice is most impressive.

The Longy School concert tonight will consist of music arranged for two pianos. The program includes the Piston Concertino for piano and orchestra, the Piano Concerto in A major and an Andante and Fugue by Mozart, and Ravel's La Valse. The practice of arranging orchestral scores for piano is one which can be very reasonably objected to on purely aesthetic grounds, for the music is certainly distorted in the process. The justification for such arrangements is a practical one. They are extremely convenient both for the student who can play them without orchestra and for the concert-goer who wishes to gain greater familiarity with music which is done only rarely on regular programs.