Note 31 — CONTENTS. (continued 3)

Not 'of course' because Tycho used it, for, like other able students of science, he made mistakes from time to time. Thus he argued that the earth cannot rotate on her axis, because if she did bodies raised above her surface would be left behind—an argument which even the mechanical knowledge of his own time should have sufficed to invalidate, though it is still used from time to time by paradoxers of our own day.