a fort or platform, surrounding the lower masthead, from which it projects on all sides like a scaffold.

The principal intention of the top is to extend the topmast shrouds, so as to form a greater angle with the mast, and thereby give additional support to the latter. It is sustained by certain timbers fixed across the hounds or shoulders of the mast, and called the treble-trees and cross-trees.

Besides the use above-mentioned, the top is otherwise extremely convenient to contain the materials necessary for extending the small sails, and for fixing or repairing the rigging and machinery with more facility and expedition. In ships of war it is used as a kind of redoubt, and is accordingly fortified for attack or defence; being furnished with swivels, musketry, and other fire-arms, and guarded by a thick fence of corded hammocks. Finally, it is employed as a place for looking out, either in the day or night.

Top-Mast, the second division of a mast, or that part which stands between the upper and lower pieces. See the article Mast.

Top-Sail, certain large sails extended across the top-masts by the topmast-yard above, and by the yard attached to the lower mast beneath; being fastened to the former by robands, and to the latter by means of two great blocks fixed on its extremities, through which the topmast sheets are inserted, passing from thence to two other blocks fixed on the inner part of the yard close by the mast; and from these latter the sheets lead downwards to the deck, where they may be slackened or extended at pleasure. See the article Sail.