of the intact one will also observe (for it has been demonstrated that mobiles of the same genus, however much they may differ in size, are moved with the same speed): and similarly, if the mobiles differ in size and in heaviness, having taken hold, from the larger, of a part that is equal to the smaller mobile, we will again have two mobiles which differ in heaviness and not in size; and this part will observe the same ratio with the other mobile in its motion, as the whole of the other intact mobile (for, again, it is with the same swiftness that the part and the whole of mobiles of the same species are moved). </s>
<s id="id.1.1.8.06.04">Thus is it evident how, if the ratio of the motions of those mobiles that differ only in heaviness and not in size is given, the ratios of those that differ in any other way are also given. </s>
<s id="id.1.1.8.06.05">And so {1}, in order that we may find this ratio and, against Aristotle's way of thinking, show that in no way do mobiles observe the ratio of their heavinesses, even if they are of different species, we will demonstrate things on which depends the answer not only to this investigation , but also to the investigation of the ratio of the motions of the same mobile in different media; and we will examine both questions simultaneously. </s>
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<s id="id.1.1.8.07.00"/>
<s id="id.1.1.8.07.01">And so let us come to the investigation </s>
