NOVEMBER 18TH.—To-day the Secretary told me, in reply to my question, that he had authentic information of the seizure of Messrs. Slidell and Mason, our commissioners to Europe, by Capt. Wilkes, of the U. S. Navy, and while on board the steamer Trent, a British vessel, at sea. I said I was glad of it. He asked why, in surprise. I remarked that it would bring the Eagle cowering to the feet of the Lion. He smiled, and said it was, perhaps, the best thing that could have happened. And he cautions me against giving passports to French subjects even to visit Norfolk or any of our fortified cities, for it was understood that foreigners at Norfolk were contriving somehow to get on board the ships of their respective nations.