It is a wretched result of the art of ballooning, if it can be turned to no better account than this. Can, then, nothing more important be brought out of it? Can it never be rendered subservient to the ordinary purposes of human life? The opinion almost universally prevalent among men, not excluding scientific men, is that it can not. Some aeronauts, indeed, assure us that the time is fast approaching when aerial transition will inevitably be placed as far before railroad and steam-boat transition as the latter are before the old-fashioned sail and horse-power modes. But the most of men place little faith in these flattering anticipations; they listen to or read them with as dogged a skepticism as they read or hear the celebrated vaticination of Bishop Wilkins, that it would be as common for man hereafter to call for his wings when about to make a journey, as it then was to call for his boots and spurs. They doubt whether, with all the characteristic marks of progress that distinguish the present age, balloons will ever become a safe, cheap, and expeditious means of traveling. Whether the aeronauts are most to be justified in their sanguine expectations, or the rest of mankind in their cautious incredulity, time alone will determine. Our judgment, we confess, strongly inclines to the side of the skeptics. Much is still desiderated, in order to the practicability of ballooning as a generally useful art. A new gas, at once cheap in its production, and of sufficient buoyancy, must be discovered. The gases at present employed for inflating balloons are either too expensive or too heavy. Hydrogen, which is almost fourteen times lighter than common air, is the lightest gas known, but the expense at which it is procured is an insuperable objection to its practical utility. To produce a quantity sufficient to raise the weight of a pound, four and a half pounds of iron or six of zinc, with equal quantities of sulphuric acid, would be required. Carbureted hydrogen or coal gas is much cheaper, and brings the cost of what may be necessary for experimental purposes--though this is by no means inconsiderable--within the compass of more ordinary means. But, as it is only about one half lighter than atmospheric air, it would require a machine of immense size to support any great weight; and the whole experience of ballooning proves the difficulty of managing a body of great magnitude. Another great desideratum in aerial navigation is a power of guiding the balloon according to a given direction--of propelling it through the atmosphere as steam-boats are propelled on the ocean. It has indeed been said that, as nature is very profuse in the variety of atmospherical currents within two miles above the level of the sea, we are not, in sailing through the air, driven to the necessity of attempting to go right against the wind, but have only to ascend or descend, as the case may be, to a current, which will waft the vessel to its desired destination.