Gate, in Architecture, a large door leading or giving entrance into an open area, as a field or court-yard, or into a considerable building, as a palace or prison. An excellent method of hanging gates of large dimensions, has been introduced by Mr. H. R. Palmer, which is a useful application of his suspension railway (see Railway). The following cut represents some sliding or rather rolling gates at each end of the northern avenue of the London Docks, between the warehouses and the basin, forming not only a useful barrier to prevent the intrusion of improper persons during the intervals of cessation of public business, but producing also an ornamental effect. During the hours of business these gates are rolled back against the side walls of the end warehouses, to which they stand close and parallel, occupying no useful room. In opening or shutting them nothing need be moved out of the way, and it is done with great facility and dispatch. Being suspended entirely from above, and not even touching the surface of the ground, it is not subjected to the adventitious obstacles common to other gates, a a is intended to represent part of the wall of the ranges of warehouses, and b the extremity of the range of sheds on the opposite side of the avenue; c c a double railway, extended entirely across the avenue from a to b, and likewise to the width of a gate beyond on each side; it is supported by slightly curved arches of wrought iron, with ornamental scroll-work between the arches and the double rail, the superstructure resting upon lofty columns of cast-iron.
One of three gates d (each of which fills up the space between two columns) is shown in the act of being closed, by a man pushing it along; from its large dimensions and great weight (though chiefly composed of wood) this could not be easily effected by the simple force of one man, but being constructed on the principle of Mr. Palmer's patent railway, the friction is reduced to very inconsiderable amount, the whole weight of each gate being entirely suspended by iron rods to the axles of the little wheels which run on the top of the railway, which are kept in their tracks by their peripheries being flanged; the gates do not rest upon or even touch the ground, but are merely guided in their course by means of a projecting edge fixed in their path: this will be easily explained by means of the annexed diagram, which represents a transverse section of these parts, f f are two plates of iron, with raised edges in the middle, which are screwed down to open sleepers g g, and above these is shown an edge view of the lower ends of the gates, which run on either side of the column h.
Gates upon the same principle have been put up at the court-yard at the Admiralty, and various other public situations.