On Wednesday evening the London String Quartet performed Beethoven's three Rasoumowski Quartets in Sanders Theater, and those who were terminate through to the best concert of the year. One of the finest of its kind in the world, the group certainly confirmed its reputation in the different program.

Beethoven had completed the Eroica and the Fifth Symphonies as well as the Waldstein and Appassionnts when he turned to the composition of the three quartets sponsored by Count Rasoumowski. At the very beginning of the first, the change in the composer is apparent: a paradoxical humor later expressed in the Eighth Symphony and an increasing tendency to write for himself which culminated in the late piano sonatas.

The English players emphasized the contrast between the gaiety and introspection, particularly in the first of the three works. A highly romantic reading of the slow movement sharply set-off the cheerful expression of the violin introducing the Russian theme of the last movement. The juxtaposition of the two moods is even clearer in the second quartet; an unusually long and searching adagio is followed by the rollicking humor of the jiggish last movement. Climaxing the whole series, the almost fugal finale of the third quartet presents complicated difficulties to the performers. Not without a little buzzing, the players carried it off.

Mr. Evans, the cellist, distinguished himself particularly in the first number; his instrument literally sang with feeling and beauty. The first violinist, Mr. Pennington, also gave a flawless performance. Unfortunately, the second violinist and the violist did not measure up to their colleagues in clarity or smoothness, but the all-important ensemble, which faltered slightly at the start, was impeccable thereafter.