Sachs's later papers were almost exclusively published in the three volumes of the "Arbeiten des botanischen Instituts in Würzburg" (1871–88). Among these are his investigation of the periodicity of growth in length, in connection with which he devised the self-registering auxanometer, by which he established the retarding influence of the highly refrangible rays of the spectrum on the rate of growth; his researches on heliotropism and geotropism, in which he introduced the clinostat; his work on the structure and the arrangement of cells in growing-points; the elaborate experimental evidence upon which he based his "imbibition-theory" of the transpiration-current; his exhaustive study of the assimilatory activity of the green leaf; and other papers of interest.