morality would be broken down by permitting aëronauts to descend into gardens and balconies; and, above all, the boundaries of empires would be practically annulled, and nations in consequence engage in continual war.
Well is it, then, for humanity that balloons have not proved a very great success. Many extensive voyages and many interesting observations have been made; but as a flying-machine the balloon has no place. It is the servant of the air, not the master. It must obey a will, pitiless, fickle, sometimes kind, but never trustworthy. The expectation that headway could be made against the wind by means of sails and rudders had no basis in sound theory or sense. A sailing-ship is immersed in two fluids of widely differing densities, and its sail is only effective because the water, while supporting, at the same time allows the vessel to move more readily in one direction than another.
Fig. 3.—Sullivan's Flying-Machine. (Taken from United States Patent-Office Reports.)
A balloon, on the other hand, is totally immersed in an ocean of air, and being of the same weight bulk for bulk, and subject to no external forces, must necessarily follow the slightest current. One might as well attempt to steer a boat, swept along by a great stream, without wind or oar. It forms an integral part of the current itself. It is a thistle-down blown by an autumn gale.