Other artists whom we knew were Mulready, Cooke—as famous for his splendid collection of old Venetian glass as for his pictures—Creswick and Elmore; but much as Rowland Hill loved art, the men of science, such as Airy, the Astronomer Royal; Smyth, the “Astronomical Admiral”; Wheatstone, Lyell; Graham, the Master of the Mint; Sabine, the Herschels, and others were to him the most congenial company. After them were counted in his regard the medical men, philosophers and economists, such as Harley, Coulson, Fergusson, the Clarkes, Sir Henry Thompson—the last to die of his old friends—and Bentham, Robert Owen, James and John Stuart Mill—these last four being among the earliest great men he knew, and counting in some ways as his mentors. Of his literary friends no two held a higher place in his esteem than Maria Edgeworth and Harriet Martineau. Of the latter and of her able, untiring help in promoting the cause of Penny Postage, mention will appear later. The former, my father, and his brother Arthur, as young men, visited at her Irish home, making the pilgrimage thither which Scott and many other literary adorers had made or were destined to make, one of the most interesting being that of Mrs. Richmond Ritchie, Thackeray's daughter, of which she tells us in her editorial preface to a recent edition of “Castle Rackrent.” The two brothers had looked forward to meet a charming woman, but she exceeded their expectations, and the visit remained in the memory of both as a red-letter day.[17] Among literary men, besides those already mentioned, or to be named later, were Leigh Hunt, De Quincey—who when under the influence of opium did the strangest things, being one day discovered by my father and a friend hiding in some East End slum under the wholly erroneous impression that “enemies” were seeking to molest him—Sir John Bowring, Dr Roget, author of “The Thesaurus,” and the Kinglakes. “Eothen,” as the writer of that once famous book of travels and of “The Invasion of the Crimea,” was habitually called by his friends, was a delightful talker; and his brother, the doctor, was equally gifted, if less fluent, while his sister was declared by Thackeray to be the cleverest woman he ever met.