The possibility of such a catastrophe is perhaps the one thing that will cause naval architects to go slowly in the adoption of the new device. We can hardly suppose that the difficulties represented are insuperable, but undoubtedly a long series of experiments will be necessary before the Schlick gyroscope will come into general use. The apparatus has been tested, however, on a German coast steamer. It may not be very long before craft of the size of Channel steamers and boats that go to Cuba and the Bermudas are equipped with the device. Naturally enough, this prospect excites the liveliest popular interest. Visions of pleasant ocean voyages come before the mind's eye of many a voyager who hitherto has dreaded the sea. But whatever the future of the gyroscope as applied to pleasure-craft, there can be little doubt about its utility as applied to vessels of war. It seems a safe enough prediction that all battle-ships will be supplied with this mechanism in the not distant future. Amid the maze of engines of destruction on war-vessels, one more will not appal the builder; while the advantage of being able to fling a storm of projectiles from a stable deck must be inestimable. IX NAVIGATING THE AIR If it were possible to regard all medieval literature without more than a grain of doubt, we must believe that aerial flight by human beings was accomplished long before science had risen even to the dignity of acquiring its name. Thus, it is recorded by a medieval historian that during the reign of Charlemagne some mysterious persons having acquired some knowledge of aerostatics from the astrologers, who were credited with numerous supernatural powers, constructed a flying-machine, and compelling a few peasants to enter it, sent them off on an aerial voyage. Unfortunately for the unwilling voyagers, so the story runs, they landed in the city of Lyons, where they were immediately seized and condemned to death as sorcerers. But the wise bishop of the city, doubting the story of their aerial journey, pardoned them and allowed them to escape. That such a fabulous tale could gain credence is explained by the prevailing belief in the powers of the astrologers and sorcerers at that time. People who could seriously believe that an alchemist could create gold and prolong life and youth indefinitely, would find nothing startling in the announcement that he could also perform the relatively simple feat of flying--a thing that birds and bats accomplish with such obvious facility. And nothing is more certain than that attempts at aerial flight have been made at various times since the beginning of history.