That is to say, _seeing the office and property of body is to press all things downwards; and on the contrary, seeing the nature of vacuum is to have no weight at all; therefore when of two bodies of equal magnitude, one is lighter than the other, it is manifest that the lighter body hath in it more vacuum than the other_. To say nothing of the assumption concerning the endeavour of bodies downwards, which is not rightly assumed, because the world hath nothing to do with downwards, which is a mere fiction of ours; nor of this, that if all things tended to the same lowest part of the world, either there would be no coalescence at all of bodies, or they would all be gathered together into the same place: this only is sufficient to take away the force of the argument, that air, intermingled with those his atoms, had served as well for his purpose as his intermingled vacuum. The third argument is drawn from this, that lightning, sound, heat and cold, do penetrate all bodies, except atoms, how solid soever they be. But this reason, except it be first demonstrated that the same things cannot happen without vacuum by perpetual generation of motion, is altogether invalid. But that all the same things may so happen, shall in due place be demonstrated. Lastly, the fourth argument is set down by the same Lucretius in these verses: Duo de concursu corpora lata Si cita dissiliant, nempe aer omne necesse est, Inter corpora quod fuerat, possidat inane. Is porro quamvis circum celerantibus auris Confluat, haud poterit tamen uno tempore totum Compleri spatium; nam primum quemque necesse est Occupet ille locum, deinde omnia possideantur.--I. 385-91.