I'd rule out "eloquent", because this has nothing otherwise to do with the paragraph.
"Articulate" is more difficult to dismiss.
But I'm not sure whether the author knows what he's saying. If laughter "would fain be prolonged ..." then isn't he saying that laughter is not "reverberating from one to another, something beginning with a crash, to continue in successive rumblings, like thunder in a mountain." It would only fain be that. So maybe it is succinct.