Lionel Harvey is going on a secret mission to Mexico. What is to be derived from it I have little guess; but there is every reason to believe that France has sent somebody there, and there is no doubt that America will endeavour, or has already got, the start of Europe upon it. Canning is very anxious not to lose the moment; and I suppose that this must be the prelude of our admitting the independence of South America; however, the mission is secret, but he is commissioned, and has the rank of Minister Plenipotentiary. It is a long and desolate prospect, but the scene will be new. He is not quite reconciled to it, but having no better prospect, I think he has done wise in accepting it; they give him two secretaries. I would not wish you to mention this appointment. I find Canning is by no means of opinion that France has or will succeed in her efforts in Spain; at least, this was the tone of his language to Lionel, who saw him yesterday. I hear from Wynn that the grand attack on Cadiz was expected to take place between the 25th and 30th July. Ever, my dear Duke, Most faithfully yours, W. H. FREMANTLE. Mr. Thomas Grenville was one of the most liberal collectors of rare books at a time when bibliomania was much more in fashion than it is now. The following is a characteristic specimen of his powers of observation when directed to his favourite pursuit:-- THE RIGHT HON. THOMAS GRENVILLE TO THE DUKE OF BUCKINGHAM. Cleveland Square, July 30, 1823. MY DEAR DUKE, I have just been collating two copies of the "Sacra Exequialia in Funere Jacobi II.--a Carolo de Aquino. Fol. Romae 1702." Whether you have this book or not, you certainly have in your Granger the famous print (belonging to this book) of a head of the _Pretender_, by _Edelinck_, _aetatis suae_ 12. In one of my copies (the presentation copy to the King of France or one of the French Royal Family) below the head, upon a _tablet_, is engraved "Cognoscunt mei me," and in the corner of the tablet "aetatis suae 12;" and on each side of the tablet is a circular _medallion_, one of which is _a library_ with "Litteris Insignis" round it. The other _medallion_ is a _man firing at a wild boar_, with "Et Armis" round it. In the _centre of the large circle_ which surrounds the head, and just above the tablet, is a _large medallion_, with the sun behind a cloud, and round it "Et latet et lucet." In the other copy, the same print (with Edelinck's name and "aetatis suae 12," in the corner of the tablet, like the other), has these variations. The _large medallion_ above the tablet has the "Arms of England with a crown." The _tablet_ has no inscription, but is left blank, except that it has in the corner "AEtatis suae 12."