To-day the Duchess of Sutherland called with the Duchess of Argyle. Miss Greenfield happened to be present, and I begged leave to present her, giving a slight sketch of her history. I was pleased with the kind and easy affability with which the Duchess of Sutherland conversed with her, betraying by no inflection of voice, and nothing in air or manner, the great lady talking with the poor girl. She asked all her questions with as much delicacy, and made her request to hear her sing with as much consideration and politeness, as if she had been addressing any one in her own circle. She seemed much pleased with her singing, and remarked that she should be happy to give her an opportunity of performing in Stafford House, so soon as she should be a little relieved of a heavy cold which seemed to oppress her at present. This, of course, will be decisive in her favor in London. The duchess is to let us know when the arrangement is completed. I never realized so much that there really is no natural prejudice against color in the human mind. Miss Greenfield is a dark mulattress, of a pleasing and gentle face, though by no means handsome. She is short and thick set, with a chest of great amplitude, as one would think on hearing her tenor. I have never seen in any of the persons to whom I have presented her the least indications of suppressed surprise or disgust, any more than we should exhibit on the reception of a dark-complexioned Spaniard or Portuguese. Miss Greenfield bears her success with much quietness and good sense. Tuesday, May 10. C. and I were to go to-day, with Mrs. Cropper and Lady Hatherton, to call on the poet Rogers. I was told that he was in very delicate health, but that he still received friends at his house. We found the house a perfect cabinet collection of the most rare and costly works of art--choicest marbles, vases, pictures, gems, and statuary met the eye every where. We spent the time in examining some of these while the servant went to announce us. The mild and venerable old man himself was the choicest picture of all. He has a splendid head, a benign face, and reminded me of an engraving I once saw of Titian. He seemed very glad to see us, spoke to me of the gathering at Stafford House, and asked me what I thought of the place. When I expressed my admiration, he said, "Ah, I have often said it is a fairy palace, and that the duchess is the good fairy." Again, he said, "I have seen all the palaces of Europe, but there is none that I prefer to this." Quite a large circle of friends now came in and were presented. He did not rise to receive them, but sat back in his easy chair, and conversed quietly with us all, sparkling out now and then in a little ripple of playfulness. In this room were his best beloved pictures, and it is his pleasure to show them to his friends.