the larger is moved faster: and that in Book IV of <i>De Caelo</i>, text #26 [311a 19-22], where he has written that any magnitude of fire is carried upward, and that which is larger, faster; and also that any magnitude of earth is moved downward, and similarly, that which is larger, faster. </s>
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<p>
<s id="id.1.1.8.02.00.fig"/>
<s id="id.1.1.8.02.01">And again, in Book III of <i>De Caelo</i>, text #26 [301a 26-32], he says: Let there be a heavy mobile b, and let it be carried along line ce, which is divided at point d; if then mobile be is divided according to the proportion in which line ce is divided at point d, it is manifest that, during the time in which the whole of it is carried along the totality of line ce, in the same time this part is moved along line cd. </s>
<s id="id.1.1.8.02.02">From this it is overtly established that Aristotle wants mobiles of the same genus to observe between themselves in the speed of motion the ratio of the sizes that these mobiles have: and he says that very openly in Book IV of the <i>De Caelo</i>, text #16 [309b 14], by affirming that a large piece of gold is carried more swiftly than a small one. {1} </s>
<s id="id.1.1.8.02.03">How ridiculous this opinion is, is clearer than daylight: for who will ever believe that if, for example, two lead balls were released from the sphere of the Moon, one being a hundred times larger than the other, if the larger took an hour to come to Earth, the smaller would use in its motion a space of time of a hundred hours? or, if from a high tower {1}, two stones, one being double the size of the other, were thrown at the same moment, that, when the smaller was at mid-tower, the larger would already have reached the ground? </s>
<s id="id.1.1.8.02.04">Or, again, if from the depth of the sea a very large beam and a small piece of the same beam begin to go up at the same time, in such a way that the beam is a hundred times larger than that piece of wood, who would ever say, that the beam will have to go up to the surface a hundred times faster?{1} </s>
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<p>
<s id="id.1.1.8.03.00"/>
<s id="id.1.1.8.03.01">But, in order that we may always make more use of reasons than of examples (for we are seeking the causes of effects, which are not reported by experience), we will bring forth our way of thinking, whose confirmation will result in the downfall of Aristotle's opinion. </s>
<s id="id.1.1.8.03.02">We say, then, that mobiles of the same species (let those things be said to be of the same species that are constituted of the same material, such as lead or wood, etc.), though they may differ in size, are however moved with the same swiftness, and a larger stone does not go down more swiftly than a smaller one. </s>
<s id="id.1.1.8.03.03">Those who are surprised by this conclusion will also be surprised that a very large beam can float on water, just as well as a small piece </s>
