ÆRIAL NAVIGATION.
When air-balloons were first discovered, some one flippantly asked Dr. Franklin what was the use of it. The philosopher answered the question by asking another:—“What is the use of a new-born infant? It may become a man.”
The first balloon-ascension was made by Pilatre de Rozier and the Marquis d’Arlandes, November 21, 1783, in a montgolfière.
A century and a half before this, John Gregorie wrote, “The air itself is not so unlike to water, but that it may be demonstrated to be navigable, and that a ship may sail upon the convexity thereof by the same reasons that it is carried upon the ocean.”
In the first number of the Philosophical Collections, 1679, is “a demonstration how it is practically possible to make a ship, which shall be sustained by the air, and may be moved either by sails or oars,” from a work entitled Prodroma, published in Italian by P. Francesco Lana. The scheme was that of making a brazen vessel which should weigh less than the air it contained, and consequently float in the air when that which was within it was pumped out. He calculated every thing—except the pressure of the atmosphere, in consequence of which slight oversight he realized no practical result.