ClassicsThe Sea and Its Living Wonders - A Popular Account of the Marvels of the Deep and of the Progress of Martime Discovery from the Earliest Ages to the Present TimeG. (Georg) Hartwig
ClassicsThe Tropical World - Aspects of man and nature in the equatorial regions of the globe.G. (Georg) Hartwig
ClassicsThe Polar World - A popular description of man and nature in the Arctic and Antarctic regions of the globeG. (Georg) Hartwig
