air against him and then the arrow would struggle against it. But it is certain the arrow ought to go much farther and faster when the movement of the air is favorable to it then when against it, as is obvious in darts sent out with a favoring wind. Ergo.
Similarly not a few other arguments can be worked out, but there are none as valuable for proof as the foregoing ones. Though these were written by me with a flying pen far from books and sick in bed with a broken leg, yet they seem to me to have so much value that I do not see any way by which they could rightly be refuted. These I have written for your gracious lordships in gratitude for your goodwill on the occasion of our conversation at your dinner four days ago; and I ask for them that you meditate on them justly and well.
