_April 20th._--The visit of the Emperor has been one continued ovation, and the success of it complete. None of the Sovereigns who have been here before have ever been received with such magnificence by the Court or by such curiosity and delight by the people. Wherever and whenever they have appeared, they have been greeted by enormous multitudes and prodigious acclamations. The Queen is exceedingly pleased with both of them; she thinks the Empress very natural, graceful, and attractive, and the Emperor frank, cordial, and true. He has done his best to please her, talked to her a great deal, amused her, and has completely succeeded. Everybody is struck with his mean and diminutive figure and vulgar appearance, but his manners are good and not undignified. He talked a very long time to Lord Derby on Tuesday at Windsor and to Lord Aberdeen on Wednesday. This last was very proper, because he had a great prejudice against Aberdeen, and fancied he was his enemy, which Aberdeen knew. When he was invested with the Garter, he took all sorts of oaths--old feudal oaths--of fidelity and knightly service to the Queen, and he then made her a short speech to the following effect:--'I have sworn to be faithful to Your Majesty and to serve you to the best of my ability, and my whole future life shall be spent in proving the sincerity with which I have thus sworn, and my resolution to devote myself to your service.' The fineness of the weather brought out the whole population of London, as usual kept in excellent order by a few policemen, and in perfect good humour. It was a beautiful sight last night when the Royal and Imperial party went to the Opera in state; the streets lit by gas and the houses illuminated and light as day, particularly opposite the Travellers' Club, where I was. I am glad the success of the visit has been so great, and the contentment of all the parties concerned so complete, but it is well that all will be over tomorrow, for such excitement and enthusiasm could not last much longer, and the inconvenience of being beset by crowds, and the streets obstructed, is getting tiresome.