Count Otto in the same despatch thus describes the evening of that brilliant 10th of March, 1810; "That evening there was a grand ball in the Hall of Apollo; the whole city was there. The Prince was greeted as enthusiastically as in the morning. The Emperor himself was present, together with the Archdukes, and received the congratulations and blessings of a populace beside itself with joy. The Prince scarcely left the Emperor, who talked with him most amiably and most cordially. The Emperor and the Vice-Constable attracted the eyes of the whole multitude that surrounded them, and every one rejoiced to see the friend and fellow-soldier of Napoleon by the side of the ruler of Austria. It was noticed that this was the first appearance of the Archduke Charles in the Hall of Apollo along with the Emperor; he will figure in the marriage ceremony, and shows the liveliest satisfaction in the event. The Vice-Constable was charmed with the Prince's conversation, and is going to dine with him to-morrow." General the Count of Lauriston had just arrived in Vienna, bringing letters from Napoleon to the Emperor and Empress of Austria. We have found the replies in the archives of the Ministry of Foreign Affairs. They are as follows:-- The letter of the Emperor of Austria to the Emperor of the French:-- "March 6, 1810. MY BROTHER: General the Count of Lauriston has given to me Your Imperial Majesty's letter of February 23. Entrusting to your hands, my brother, the fate of my beloved daughter, I give to Your Majesty the strongest possible proof that I could give of my confidence and esteem. There are moments when the holiest of the affections outweighs every other consideration which is foreign to it. May Your Imperial Majesty find nothing in this letter but the feelings of a father, attached, by eighteen years of pleasant intercourse, to a daughter whom Providence has endowed with all the qualities that constitute domestic happiness. Though called far away from me, she will continue to be worthy of my most enduring affections only by contributing to the felicity of the husband whose throne she is to share, and to the happiness of his subjects. You will kindly receive the assurance of my sincere friendship, as well as of the high consideration with which I am, my brother, Your Imperial and Royal Majesty's affectionate brother FRANCIS." The letter of the Empress of Austria to the Emperor Napoleon:--