 Amid his concert and teaching duties , Grainger found time to rescore many of his works ( a habit he continued throughout his life ) and also to compose new pieces : his Children 's March : Over the Hills and Far Away , and the orchestral version of The Power of Rome and the Christian Heart both originated in this period . He also began to develop the technique of elastic scoring , a form of flexible orchestration which enabled works to be performed by different numbers of players and instrument types , from small chamber groups up to full orchestral strength . 
