This morning appears in all the newspapers the autograph letter of the Emperor Napoleon to the Emperor Nicholas, which has been so much talked of. If the Emperor of Russia at once closes with it, he will place us in a great dilemma, but it may produce peace. On Sunday Clarendon told me all about this letter. The Emperor took it into his head to write it, and sent a copy here for the approval of our Government. Clarendon made many objections, particularly to the suggestion of a simultaneous withdrawal of the Russian troops and the Allied fleets, and to the separate negotiation of Turkey, two points we had all along laid great stress upon. Walewski returned the letter with the objections raised by us, and soon after informed Clarendon that the letter had been altered according to our suggestions, and the objectionable parts omitted; but he did not bring him the amended letter. Clarendon wrote to Cowley, and said what had passed, and that he was glad the alterations had been made, but was surprised the letter, as altered, had not been shown to him. Cowley told Drouyn de Lhuys, who said they had sent the letter to Walewski, and he could not think why Clarendon had not seen it, and he wrote to Walewski desiring him to take it to Clarendon. He did so, when, much to his annoyance as well as surprise, he found that they had only made a few verbal alterations, and left the really objectionable parts nearly the same as before. This may put us in a very awkward position. If the Emperor Nicholas agrees, we must either agree also to what we entirely disapprove, or disavow the French, and perhaps separate from them; and it will be very embarrassing if the Government are asked in Parliament whether they were a party to this letter and its proposals. Clarendon told me this was only one of many instances in which the conduct of the French had been very _louche_ and insincere. He thinks this more attributable to Drouyn than to his master, and Walewski has behaved with great loyalty and straightforwardness; but hardly a week has passed that he has not had to complain of something done by the French Government in a separate or clandestine manner, or of some proposal which they ought not to make, and this makes one of the difficulties of the position of which nobody is aware--a fine prospect to be married to such a people on a great question; but what can be expected from the Government of such a Sovereign and such Ministers? It confirms my long settled opinion, that we are always in extreme danger of being thrown over by them. With regard to the whole question (and omitting these details) the Emperor Napoleon has behaved well enough to us; for he has adhered steadily to the joint policy, though it is his interest to maintain peace, and public opinion in France runs as strongly that way as here it runs in the opposite direction.