Handbuch der physiologischen Optik was published as Vol. ix of Gustav Karsten's Allgemeine Encyklopädie der Physik. Helmholtz's introduction to the work states that it originally appeared in three parts, the first in 1856, the second in 1860 and the third in 1866. Horblit owned a copy in six parts published between 1856 and 1867.--J. Norman, 2006.