Having thus briefly traced the history of aeronautics, we shall now inquire into the practical value of the art. After the discovery of the hydrogen-gas balloon, the most extravagant projects dazzled and bewildered the minds of men. To journey through the air from one part of the globe to another, or even to circumnavigate the globe itself, in balloons, was child's play, compared with the magnificent results that were anticipated. It was fondly expected that the new discovery would open up a channel of communication between the earth and its sister planets, and that the time was not far distant when men would be embarking from the Earth, in a balloon, for the Moon, or for Mercury, Venus, Mars, the Asteroids, or some of the other planets, just as they embarked in a ship for France, Italy, India, China, Africa, or America. They forgot that the laws of gravitation, which bind man as by chains of adamant to this world, would ever interpose an insurmountable obstacle to the realization of such wild imaginings; that the atmosphere has its limits as well as the ocean, extending, it is calculated, not much beyond forty miles above the earth's surface; that, at a certain height, it is as light, by reason of its rarity, as the lightest gas with which a balloon can be inflated, thereby rendering all farther ascent impossible; and that, even before the aeronaut had reached that height, very serious consequences would ensue from the intense cold, from the diminution of atmospheric pressure, and from the inadequacy of a too rarified atmosphere for supporting respiration. Such overwrought expectations, however, produced by the first excitement of a great discovery, soon subsided, when men began soberly to reflect on the immutable laws, or, which is the same thing, the powerful mandate of the Creator, which confines all things within their appointed sphere.