THERE are now dawnings of two possible solutions of the problem of aerial navigation; a problem which has impassioned men for perhaps 4,000 or 5,000 years. Navigable balloons have recently been developed to what is believed to be nearly the limit of their efficiency, and after three intelligent but unfortunate attempts by others, a successful dynamic flying machine seems to have been produced by the Messrs. Wright.
It is therefore interesting to review the present status of the question, the prospects of its solution and the probable uses of the hoped-for air-ships.
As to balloons, we may pass over the early gropings and failures to make them navigable. It was recognized very soon that the spherical balloon was the sport of the wind, that it was necessary to elongate it in order to evade the resistance of the air, and that, inasmuch as aerial currents are much more rapid than aqueous currents, it was necessary to obtain considerable speeds in order to have a useful air-ship. This means that there must be great driving power, and that this power shall weigh as little as possible; for in any case the balloon itself with its adjuncts and passengers will absorb the greater part of its lifting power.
Giffard was the first to apply in 1852 an artificial motor to an elongated balloon. This motor consisted in a steam-engine of three horse power, which weighed with its appurtenances 462 pounds, and
- Paper read before Section D, American Association for the Advancement of Science, December 30, 1903.