what did gulliver see when he had hurd a nocking for above an hour ?

From the text:

When the people observed I was quiet, they discharged no more arrows; but, by the noise I heard, I knew their numbers increased; and about four yards from me, over against my right ear, I heard a knocking for above an hour, like that of people at work; when turning my head that way, as well as the pegs and strings would permit me, I saw a stage erected about a foot and a half from the ground, capable of holding four of the inhabitants, with two or three ladders to mount it: from whence one of them, who seemed to be a person of quality, made me a long speech, whereof I understood not one syllable.