There is a remarkable picture, by Van Dyk, of the Duke of Vieuxville, ambassador from the Court of France to Charles the First, who with chivalrous devotion followed the King into the field and was killed at Newbury. The dress is old, but picturesque;--a white 'juste-au-corps, à la Henri Quatre,' with a black mantle thrown over it; full short black breeches falling over the knee, with silver points; pale violet stockings with gold clocks, and white shoes with gold roses. On the mantle is embroidered the star of the Holy Ghost, four times as large as it is now worn, the blue riband 'en sautoir,' but hanging down very low, and the cross worn in the present fashion, on the side; it is narrower and smaller than now, and hangs by the broad riband almost under the arm. The Duke de Guise was not such as I had pictured him to myself:--a pale face with reddish beard and hair; with the expression rather of an 'intriguant' than of a great man.--A picture which corresponds better with the character of the person it represents is Count Gondemar, Spanish ambassador to the Court of James the First, by Velasquez; he ingratiated himself with the King by his dog-Latin, in which burlesque form he made free to say anything. He brought the gallant Sir Walter Raleigh to the scaffold by his Jesuitical intrigues. A picture of Cromwell, by his Court painter Richardson, has a double interest for the family. It was painted expressly for one of the Duke's ancestor's, who appears in the same picture as page, in the act of tying the Protector's scarf. This portrait is not much like the others of the same personage I have seen; it represents him as younger, and of a more refined nature, and is therefore probably flattered. From the hand of a Court painter this is to be expected. I must only mention two fine and large Teniers', one of which represents three wonderfully characteristic Dutch boors, meeting in a village and gossiping with their pipes in their mouths; an excellent Ruysdael; six famous Rembrandt's, and Titian's lovely mistress. I admired, too, a new specimen of art,--two Sèvres cups with miniatures after Pétitot, by that admirable porcelain-painter Madame Janquotot. The one represents Ninon de l'Enclos, of whom I had never before seen a picture that answered to my idea of her. This expressed her character fully, and is of the most attractive beauty,--genuine French, lively as quicksilver, bold almost to impudence, but too generous and too truly natural to leave any other than an engaging impression on the mind. The other--a gentle, placid, and voluptuous beauty--- was inscribed, Françoise d'Orleans de Valois. As thoroughly initiated in French genealogies and memoirs, you will know who she is. 'Je l'ignore.' Each cup cost a thousand francs. In a beautiful moonlight we drove to Aylesbury, whence I now write. _Uxbridge, Jan. 12th._