"The material world," continued Dupin, "abounds with very strict analogies to the immaterial; and thus some color of truth has been given to the rhetorical dogma, that metaphor, or simile, may be made to strengthen an argument, as well as to embellish a description. The principle of the _vis inertiæ_, for example, seems to be identical in physics and metaphysics. It is not more true in the former, that a large body is with more difficulty set in motion than a smaller one, and that its subsequent _momentum_ is commensurate with this difficulty, that it is in the latter, that intellects of the vaster capacity, while more forcible, more constant, and more eventful in their movements than those of inferior grade, are yet the less readily moved, and more embarrassed and full of hesitation in the first few steps of their progress. Again; have you ever noticed which of the street signs over the shop doors are the most attractive of attention?" "I have never given the matter a thought," I said. "There is a game of puzzles," he resumed, "which is played upon a map. One party playing requires another to find a given word--the name of town, river, state, or empire--any word, in short, upon the motley and perplexed surface of the chart. A novice in the game generally seeks to embarrass his opponents by giving them the most minutely lettered names; but the adept selects such words as stretch, in large characters, from one end of the chart to the other. These, like the over-largely lettered signs and placards of the street, escape observation by dint of being excessively obvious; and here the physical oversight is precisely analogous with the moral inapprehension by which the intellect suffers to pass unnoticed those considerations which are too obtrusively and too palpably self-evident. But this is a point, it appears, somewhat above or beneath the understanding of the Prefect. He never once thought it probable, or possible, that the minister had deposited the letter immediately beneath the nose of the whole world, by way of best preventing any portion of that world from perceiving it. "But the more I reflected upon the daring, dashing, and discriminating ingenuity of D----; upon the fact that the document must always have been _at hand_, if he intended to use it to good purpose; and upon the decisive evidence, obtained by the Prefect, that it was not hidden within the limits of that dignitary's ordinary search--the more satisfied I became that, to conceal this letter, the minister had resorted to the comprehensive and sagacious expedient of not attempting to conceal it at all. "Full of these ideas, I prepared myself with a pair of green spectacles, and called one fine morning, quite by accident, at the ministerial hôtel. I found D---- at home, yawning, lounging, and dawdling, as usual, and pretending to be in the last extremity of _ennui_. He is, perhaps, the most really energetic human being now alive--but that is only when nobody sees him.