The Cleverest Son

An old man once knew he was going to die soon. He called his three sons and explained that there was no way that he could divide his farm in three for them. He gave them each a coin and told them that whoever could fill the room would get the farm. The first son bought a cart of hay. The second son bought a wagon of feathers. The third thought a bit, then went to a small store and bought two small objects, and slipped them in his pocket. The first son could not fill the room. the second couldn’t either. The third son took the objects out of his pocket and they filled the room. What were they?