CHAPTER 9.. 1837-1839: Age 30-32.

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."