not on the basis of summation, as Austro-German symphonies did, but on one of accumulation. Partly owing to the melodic and structural intricacies involved in this accumulation and partly due to the composer's nature, Tchaikovsky's music became intensely expressive. This intensity was entirely new to Russian music and prompted some Russians to place Tchaikovsky's name alongside that of Dostoevsky. German musicologist Hermann Kretzschmar credits Tchaikovsky in his later symphonies with offering "full images of life, developed freely, sometimes even dramatically, around psychological contrasts ... This music has the mark of the truly lived and felt experience". Leon Botstein, in elaborating on this comment, suggests that listening to Tchaikovsky's music "became a psychological mirror connected to everyday experience, one that reflected on the dynamic nature of the listener's own emotional self". This active engagement with the music "opened for the listener a vista of emotional and psychological tension and an extremity of feeling that possessed relevance because it seemed reminiscent of one's own 'truly lived and felt experience' or one's search for intensity in a deeply personal sense". Repetition As mentioned above, repetition was a natural part of Tchaikovsky's music, just as it is an integral part of Russian music. His use of sequences within melodies (repeating a tune at a higher or lower pitch in the same voice) could go on for extreme length. The problem with repetition is that, over a period of time, the melody being repeated remains static, even when there is a surface level of rhythmic activity added to it. Tchaikovsky kept the musical conversation flowing by treating melody, tonality, rhythm and sound color as one integrated unit, rather than as separate elements. By making subtle but noticeable changes in the rhythm or phrasing of a tune, modulating to another key, changing the melody itself or varying the instruments playing it, Tchaikovsky could keep a listener's interest from flagging. By extending the number of repetitions, he could increase the musical and dramatic tension of a passage, building "into an emotional experience of almost unbearable intensity", as Brown phrases it, controlling when the peak and release of that tension would take place. Musicologist Martin Cooper calls this practice a subtle form of unifying a piece of music and adds that Tchaikovsky brought it to a high point of refinement. (For more on this practice, see the next section.) Orchestration Like other late Romantic composers, Tchaikovsky relied heavily