Sentence:  Leibourn Caſtle, Kent. A proſpect of the front of that caſtle. Over the gate, we are told, was a <WSD>machicolation</WSD> or contrivance, from whence, in caſe of a ſudden attack, great ſtones, boiling water, or melted lead, might be thrown down upon the aſſailants. 
Meaning of the word marked with <WSD> tags:  An opening between corbels that support a projecting parapet, or in the floor of a gallery or the roof of a portal, of a fortified building from which missiles can be shot or heated items dropped upon assailants attacking the base of the walls.