to the product of the time and impetus, so the space to the space when the motion is uniform_; you come in with, _nay, rather as the time to the time_; as if the parallelograms A I, and A H, were not also as the times A B, and A F. Thus it is, when men venture upon ways they never had been in before, without a guide. In the corollary, you are offended with the permutation of the proportion of times and lines, because you think, (you that have scarce one right thought of the principles of geometry), that line and time are heterogeneous quantities. I know time and line are of divers natures; and more, that neither of them is _quantity_. Yet they may be both of them _quanta_, that is, they may _have quantity_; but that their quantities are heterogeneous is false. For they are compared and measured both of them by straight lines. And to this there is nothing contrary in the place cited by you out of Clavius; or if there were, it were not to be valued. And to your question, what is the proportion of an _hour_ to an _ell_? I answer, it is the same proportion that _two hours_ have to _two ells_. You see your question is not so subtle as you thought it. By and bye you confess that in times and lines there is _quid homogeneum_ (this _quid_ is an infallible sign of not fully understanding what you say); which is false if you take it of the lines themselves; though if you take it of their quantities, it is true without a _quid_. Lastly, you tell m”e how I might have expressed myself so as it might have been true. But because your expressions please me not, I have not followed your advice.