without regard to any other circumstances whatever. If it was furnished with the means of accomplishing a rate of motion equal to ten miles an hour, it would experience a certain amount of atmospheric resistance due to that rate; and this amount of resistance with all its concomitant consequences, neither more nor less, would it experience, whether it endeavoured to make this way _against_ a wind blowing at the rate of 100 miles an hour, or _with_ the same in its favour. The result, so far as regards its distance from the place of starting, would, I grant, be very different; but at present we are only considering the conditions of its motion through the _air_, and these, I repeat, would be the same whatever the rate or course of the wind; so that all speculations on this score must resolve themselves into questions of _quantity_, not of _quality_, in the effect sought to be accomplished: in other words, all consideration of the rate of the wind must be left out of the argument, except, in so far as it shall be taken to regulate the limit which shall be assigned to the rate of the aerial machine, as sufficient to justify its claims to the title of a successful mode of navigating the skies.[A] [Footnote A: The condition of a Balloon propelled by machinery is very analogous to that of a boat in the water driven by oars or paddles. Suppose such a boat to be rowing or paddling up a river against the stream, if a piece of cork be thrown overboard it appears to be carried away with the current. But this is delusive; it is the boat _alone_ which really moves away from the cork. For if the boat be left to its own course, both it and the cork will float down together; and if the use of the oars or paddles be resumed, the distance between the boat and the cork will proceed to develope itself exactly according to the rate of the _boat_, without any regard to that of the _stream_. If the stream be excessively rapid, the boatsmen will appear to be exercising very great force to enable them to stem the torrent and avoid being carried backward. Now the resistance which they experience and all its attendant effects are only those which they create for themselves, and which they would experience in exactly the same degree were they to endeavour to move _at the same rate_ in calm water or with the current in their favour. If the current be at the rate of ten miles an hour and they are just able to maintain their place, they are proceeding at the rate of ten miles an hour, and they experience the opposition due to that rate of motion; precisely the same as they would experience if they sought to accomplish the same rate of motion under any other circumstances. And if the current were 100 miles an hour, they would suffer no more from endeavouring to go against it, with the force just ascribed to them, than if they were to exercise the same force in any other direction, or in a water perfectly tranquil. Apply this reasoning to the case of a Balloon