It may be replied, that the idea of a world within a world, is absurd. But, who can assert with confidence, that this idea is, in reality, nothing more than the imagination of a feverish brain? How is it shown that such a form does not exist? Are there not as strong reasons for believing that the earth is constituted of concentric spheres, as the court of Spain, or any man in Europe, had to believe that there was an undiscovered continent? Has not Captain Symmes theoretically proven his assertions of concentric spheres and open poles, and embodied a catalogue of facts, numerous and plausible, in support of his opinions? And who has confuted his assertions? I _dare_ to say, that none can be found, who _can_ fully disprove them, and account for the facts which he adduces as the proofs of his theory. Is there not the same reason to believe, that the earth is hollow, as there is to place implicit confidence in the opinion, that the planets are inhabited? And yet the one has been ridiculed as the wild speculations of a madman, while the other receives credit among the most enlightened. If it can be shown that Symmes's Theory is probable, or has the least plausibility attached to it,――nay, that it is even possible,――why not afford him the means of testing its correctness? The bare possibility of such a discovery, ought to be a sufficient stimulus to call forth the patronage of any government. And should the theory prove correct, and the adventure succeed, would it not immortalize our nation? The fame of Symmes, and his native country, would only expire with time! But, even should the expedition fail in the main object, there would still be neither loss nor disgrace. If the interior world have no existence but in Captain Symmes's imagination, would it be a matter worthy of no consideration to explore the northern parts of our own hemisphere? In the attempt, we might discover something of great importance――in chasing a phantom, we might hit on a reality――in searching for the "unknowable," discover what has hitherto been unknown; some new islands; some undiscovered sea; some north-west by west passage, or inlet; some new phenomenon of nature; some hitherto unknown inhabitants of the polar regions; nay, even the pole itself. And would it be a matter of no consequence, that a citizen of our own country should first stand on the axis, and plant the stars and stripes of our own country beneath the polar star? And should this be effected, will not the glory and honour our nation would acquire thereby, be worth the expenditure? No one, I hope, will say that it would not be worth it all, ten times told. But in case _this_ should fail, would it be a matter of no consequence, to explore the northern parts of our own continent, and fill up the blank on the map of the northern hemisphere? This, in my humble opinion, is far from being impracticable. A steam vessel might run from the mouth of the Oregon