Enters upon his Professorship at Neuchatel.--First Lecture. --Success as a Teacher.--Love of Teaching.--Influence upon the Scientific Life of Neuchatel.--Proposal from University of Heidelberg.--Proposal declined.--Threatened Blindness. --Correspondence with Humboldt.--Marriage.--Invitation from Charpentier.--Invitation to visit England.--Wollaston Prize.--First Number of "Poissons Fossiles."--Review of the Work. CHAPTER 8. 1834-1837: AGE 27-30. First Visit to England.--Reception by Scientific Men.--Work on Fossil Fishes there.--Liberality of English Naturalists.--First Relations with American Science.--Farther Correspondence with Humboldt.--Second Visit to England.--Continuation of "Fossil Fishes."--Other Scientific Publications.--Attention drawn to Glacial Phenomena.--Summer at Bex with Charpentier.--Sale of Original Drawings for "Fossil Fishes."--Meeting of Helvetic Society.--Address on Ice-Period.--Letters from Humboldt and Von Buch. CHAPTER 9. 1837-1839: AGE 30-32. Invitation to Professorships at Geneva and Lausanne.--Death of his Father.--Establishment of Lithographic Press at Neuchatel. --Researches upon Structure of Mollusks.--Internal Casts of Shells. --Glacial Explorations.--Views of Buckland.--Relations with Arnold Guyot.--Their Work together in the Alps.--Letter to Sir Philip Egerton concerning Glacial Work.--Summer of 1839.--Publication of "Etudes sur les Glaciers." CHAPTER 10. 1840-1842: AGE 33-35. Summer Station on the Glacier of the Aar.--Hotel des Neuchatelois. --Members of the Party.--Work on the Glacier.--Ascent of the Strahleck and the Siedelhorn.--Visit to England.--Search for Glacial Remains in Great Britain.--Roads of Glen Roy.--Views of English Naturalists concerning Agassiz's Glacial Theory.--Letter from Humboldt.--Winter Visit to Glacier.--Summer of 1841 on the Glacier.--Descent into the Glacier.--Ascent of the Jungfrau. CHAPTER 11. 1842-1843: AGE 35-36. Zoological Work uninterrupted by Glacial Researches.--Various Publications.--"Nomenclator Zoologicus."--"Bibliographia Zoologiae et Geologiae."--Correspondence with English Naturalists. --Correspondence with Humboldt.--Glacial Campaign of 1842. --Correspondence with Prince de Canino concerning Journey to United States.--Fossil Fishes from the Old Red Sandstone.--Glacial Campaign of 1843.--Death of Leuthold, the Guide. CHAPTER 12. 1843-1846: AGE 36-39. Completion of Fossil Fishes.--Followed by Fossil Fishes of the Old Red Sandstone.--Review of the Later Work.--Identification of Fishes by the Skull.--Renewed Correspondence with Prince Canino about Journey to the United States.--Change of Plan owing to the Interest of the King of Prussia in the Expedition.--Correspondence between Professor Sedgwick and Agassiz on Development Theory.--Final Scientific Work in Neuchatel and Paris.--Publication of "Systeme Glaciaire."--Short Stay in England.--Farewell Letter from Humboldt. --Sails for United States. CHAPTER 13. 1846: AGE 39.