once-divided deck is always called the main-deck. In a three-decker the next is called the middle-deck, and the lowest deck on which guns are carried the lower-deck. Below this again is one still lower-deck called the orlop-deck. A two-decked ship has no middle-deck, but possesses only a main and lower-deck, besides the before-mentioned quarter-deck, gangway, and forecastle. The deck on which a frigate's single battery is carried is always called her main-deck, because the sailors are wont to denominate the upper-deck of every ship carrying guns the main-deck. In a sloop-ship or corvette the only deck, without any one above it on which guns are carried, is thus invariably called the main-deck, and, as has before been said, the one beneath it on which the officers and crew live, and which has no guns, the gun-deck. Ships which have their only gun-deck running fore and aft for the same height all along are called flush-decked ships. When the after-part of the deck is raised they are known as being deep-waisted, as is the case with many merchantmen. The highest deck of many men-of-war of all rates is often perfectly level, but others have a short raised deck, extending from just before the mizen-mast to the stern, which is called the poop, and in many instances serves as a cover to the captain's cabin. When the admiral is on board he occupies the after-cabins on the upper-deck. In small men-of-war no cabins are placed under the poop, nor are they ever under the topgallant forecastle. On board merchantmen, however, where the poop is of sufficient elevation and extent to allow of it, the best cabins are always placed under it, while the crew are almost invariably berthed under the top-gallant forecastle. Of course, speaking of men-of-war, we are referring to ships as they were till the invention of low-sided armour-plated craft, which necessitated a great, if not an entire, change of terms, and the introduction of a considerable number of new ones.