CHAPTER 21.. 1865-1868: Age 58-61.

1865-1868: AGE 58-61.

Letter to his Mother announcing Journey to Brazil.--Sketch of Journey.--Kindness of the Emperor.--Liberality of the Brazilian Government.--Correspondence with Charles Sumner.--Letter to his Mother at Close of Brazil Journey.--Letter from Martius concerning Journey in Brazil.--Return to Cambridge.--Lectures in Boston and New York.--Summer at Nahant.--Letter to Professor Peirce on the Survey of Boston Harbor.--Death of his Mother.--Illness. --Correspondence with Oswald Heer.--Summer Journey in the West. --Cornell University.--Letter from Longfellow.