FOREIGN INTELLIGENCE. Our foreign expresses have reached us via Billingsgate, and are full of interesting matter. Captain Fitz-Flammer is in prison at Boulogne, for some trifling misunderstanding with a native butcher, about the settlement of an account; but we trust no time will be lost by our government in demanding his release at the hands of the authorities. The attempt to make it a private question is absurd; and every Englishman’s blood will simmer, if it does not actually boil, at the intelligence. Fitz-Flammer was only engaged in doing that which many of our countrymen visit Boulogne expressly to do, and it is hard that he should have been intercepted in his retreat, after accomplishing his object. To live at the expense of a natural enemy is certainly a bold and patriotic act, which ought to excite sympathy at home, and protection abroad. The English packet, the City of Boulogne, has turned one of its imitation guns directly towards the town, which, we trust, will have the effect of bringing the French authorities to reason. It is expected that the treaty will shortly be signed, by which Belgium cedes to France a milestone on the north frontier; while the latter country returns to the former the whole of the territory lying behind a pig-stye, taken possession of in the celebrated 6th vendemiaire, by the allied armies. This will put an end to the heart-burnings that have long existed on either side of the Rhine, and will serve to apply the sponge at once to a long score of national animosities. Our letters from the East are far from encouraging. The Pasha has had a severe sore-throat, and the disaffected have taken advantage of the circumstance. Ibrahim had spent the two last nights in the mountains, and was unfurling his standard, when our express left, in the very bosom of the desert. Mehemet Ali was still obstinate, and had dismissed his visier for impertinence. The whole of Servia is in a state of revolt, and the authorities have planted troops along the entire line, the whole of whom have gone over to the enemy. It is said there must be further concessions, and a new constitution is being drawn up; but it is not expected that any one will abide by it. Mehemet attempted to throw himself upon the rock of Nungab, with a tremendous force, but those about him wisely prevented him from doing so. We have received China (tea) papers to the 16th. There is nothing in them.