WORKS BY DR. HARTWIG. 



THE SEA AND ITS LIVING. WONDERS. With 



12 Plates and 303 Woodcuts. 8vo. 7s. net. 



THE TROPICAL WORLD. With 8 Plates and 



172 Woodcuts. 8vo. 7s. net. 



THE POLAR WORLD. With 3 Maps, 8 Pla es, 

 and 85 Woodcuts. 8vo. 7s. net. 



THE SUBTERRANEAN WORLD. With 3 Maps 



and 80 Woodcuts. 8vo. 7s. net. 



THE AERIAL WORLD. With Map, 8 Plates, 

 and 60 Woodcuts. 8vo. 7s. net. 



London : LONGMANS, GREEN, & CO. 



