_B._ The streams of air that from every side meeting together, and turning in an infinite number of small points, do pierce the bladder in innumerable places with great violence at once, like so many invisible small wimbles, especially if the bladder be a little blown before it be put in, that it may make a little resistance. And when the air has once pierced it, it is easy to conceive, that it must afterward by the same violent motion be extended till it break. If before it break you let in fresh air upon it, the violence of the motion will thereby be tempered, and the bladder be less extended; for that also they have observed. Can you imagine how a bladder should be extended and broken by being too full of emptiness? _A._ How come living creatures to be killed in this receiver, in so little a time as three or four minutes of an hour? _B._ If they suck into their lungs so violent a wind thus made, you must needs think it will presently stop the passage of their blood; and that is death; though they may recover if taken out before they be too cold. And so likewise will it put out fire; but the coals taken out whilst they are hot will revive again. It is an ordinary thing in many coal-pits, whereof I have seen the experience, that a wind proceeding from the sides of the pit every way, will extinguish any fire let down into it, and kill the workmen, unless they be quickly taken out. _A._ If you put a vessel of water into the receiver, and then suck out the air, the water will boil; what say you to that? _B._ It is like enough it will dance in so great a bustling of the air; but I never heard it would be hot. Nor can I imagine how vacuum should make anything dance. I hope you are by this time satisfied, that no experiment made with the engine at Gresham College, is sufficient to prove that there is, or that there may be vacuum. _A._ The world you know is finite, and consequently, all that infinite space without it is empty. Why may not some of that vacuum be brought in, and mingled with the air here? _B._ I know nothing in matters without the world. _A._ What say you to Torricellio’s experiment in quicksilver, which is this: there is a basin at A filled with quicksilver, suppose to B, and C D a hollow glass pipe filled with the same, which if you stop with your finger at B, and so set it upright, and then if you take away your finger, the quicksilver will fall from C downwards but not to the bottom, for it will stop by the way, suppose at D. Is it not therefore necessary that that space between C and D be left empty? Or will you say the quicksilver does not exactly touch the sides of the glass pipe? _B._ I will say neither. If a man thrust down into a vessel of quicksilver a blown bladder, will not that bladder come up to the top? _A._ Yes, certainly, or a bladder of iron, or anything else but gold. _B._ You see then that air can pierce quicksilver. _A._ Yes, with so much force as the weight of quicksilver comes to.