reverses of the Crimean war, Russia agreed not to maintain a fleet there; and it was not till 1870 that taking advantage of the critical position of the other great Powers, she declared that this article of the treaty was abrogated. She has now a strong fleet of iron-clads and other steamers in the sea, but the actual strength of this fleet is unknown except to herself. It was certainly powerful three years ago, and is doubtless much more powerful now. A vessel and crew which has navigated the "Bad Black Sea." as the Turks call it, has nothing to fear from the broadest ocean. But this sea is liable at any moment to be a closed one to Russia. No Russian man-of-war has, we believe, ever sailed into or out of it; no merchantman can enter or leave it except by the Bosporus and the Dardanelles, which are its gates, and of these gates Turkey holds the keys. The Black Sea is joined to the deep, narrow Sea of Marmora by the straits of the Bosporus, twenty miles long and from three-quarters of a mile to two and a half miles wide. Just where the straits open out into the Sea of Marmora stands Constantinople, a spot marked out by nature as the one on the whole globe best fitted for the site of a great metropolis. At its western extremity the Sea of Marmora--about one hundred miles long, with a maximum breadth of forty-three miles--contracts into the straits usually called the Dardanelles, which is properly the name of four castles, which, two on each side, command the passage, here less than a mile wide. Both straits could easily be so fortified as to be impassable by the combined navies of the world; and even now we suppose that only the best armored iron-clads could safely undertake to force the passage, in or out, of the Dardanelles. Let us now consider the fearful preponderance which Russia would gain by the possession of these straits, including of course that half of European Turkey bordering upon them. We have seen that the shores of the Black Sea furnish every facility for the construction of a navy of any required strength, and its waters afford ample space for its training. With these approaches in her grasp, Russia might in ten years construct and discipline her fleet there, perfectly safe from molestation by the navies of Europe. Fleets built and equipped at Sebastopol, Kherson, and Nicolaief, could sweep through the Dardanelles, closed to all except themselves, enter the Archipelago and the Mediterranean, and dominate over their shores and over the commerce of every nation which has to use these waters as a highway. In case of its happening at any time to find itself overmatched, the Russian fleet could repass the gates of the Dardanelles, and be as safe from pursuit as an army would be if sheltered behind the rocks of Gibraltar.