I could indeed have wished to present to my readers more original letters and extracts from Journals. These form the most valuable part of many biographies; for, independently of any intrinsic excellence of their own, they are full of interest, as bearing the marked impress of personal character, and enabling the subject of the biography to speak for himself. But here my materials fail me. My father was no great letter-writer. His pen was indeed constantly busy in valuable professional notes and official reports, clear in style and comprehensive in scope, of which specimens are given in the Appendix. But I find few characteristic letters, embodying his personal opinions and feelings; and he does not appear to have preserved, except in a few cases, the numerous letters from eminent persons, which he must have received. I have had therefore to rely on personal recollection to supply the deficiency, and to endeavour in the last chapter to describe his private life and character, as it appeared to those who knew him and loved him best. Nor are his Journals altogether fit for reproduction. They are indeed invaluable as authorities. During his foreign tours they were copious and detailed, and almost the whole of Chapter II. is drawn from them. But they were mostly notes for practical use, and, before they could be published, they would need alterations and developments, which he alone had the right to give them. During his professional life they contained simply brief memoranda of every day’s work. I could not therefore quote them with advantage, but I have found them of the greatest value in ascertaining facts and fixing dates, which otherwise might have escaped me.