HELMHOLTZ, H. v. Vorlesungen über theoretische Physik. 2. durchges. Abdruck. Lpz., 1922. 6 vols. Lge-8°. Ohcl. (Traces of use (in a library) and wear). -- Added: L. KOENIGSBERGER. Hermann v. Helmholtz. Braunschweig, 1902-03. 3 vols. Each vol. w. front. portr. Fine cont. marbled cf. w. marbled brds. -- And 3 o. in 4 vols. -- Tog. 13 vols.