A few more notes as to Darwin's character will help the reader to appreciate his work. His friendships were remarkable, characterized on his side by the warmest and most generous feeling. Henslow, Fitzroy, Lyell, Hooker, and Huxley stand out as his chief friends and correspondents. Henslow was professor of botany at Cambridge, and took Darwin with him when a student there for walks, collecting plants and insects. His admiration for Henslow's character, and his tribute to his fine simplicity and warmth of feeling in matters involving the wrongs of a down-trodden class or cruelty to an individual, are evidence of deep sympathy between the natures of Darwin and his first teacher. Of Fitzroy, the captain of H.M.S. Beagle--with whom he quarreled for a day because Fitzroy defended slavery--Darwin says that he was in many ways the noblest character he ever knew. His love and admiration for Lyell were unbounded. Lyell was the man who taught him the method--the application of the causes at present discoverable in nature to the past history of the earth--by which he was led to the solution of the question as to the origin of organic forms on the earth's surface. He regarded Lyell, who with Mrs. Lyell often visited him at Down, more than any other man as his master and teacher. Hooker--still happily surviving from among this noble group of men--was his "dear old friend"; his most constant and unwearied correspondent; he from whom Darwin could always extract the most valuable facts and opinions in the field of botanical science, and the one upon whose help he always relied. Huxley was for Darwin not merely a delightful and charming friend, but a "wonderful man,"--a most daring, skillful champion, whose feats of literary swordsmanship made Darwin both tremble and rejoice. Samples of his correspondence with these fellow-workers are given below. The letter to Hooker (September 26th, 1862) is particularly interesting, as recording one of the most important discoveries of his later years,--confirmed by the subsequent researches of Gardiner and others,--and as containing a pretty confession of his jealous desire to exalt the _status_ of plants. Often he spoke and wrote in his letters of individual plants with which he was experimenting as "little rascals." Darwin shared with other great men whose natures approach perfection, an unusual sympathy with and power over dogs, and a love for children. The latter trait is most beautifully expressed in a note which was found amongst his papers, giving an account of his little girl, who died at the age of ten years. Written for his own eyes only, it is a most delicate and tender composition, and should be pondered side by side with his frank and--necessarily to some readers--almost terrifying statement of his thoughts on religion.